Smallpox vaccine side effects


Smallpox Vaccine

Smallpox is a serious, contagious, and sometimes fatal infection caused by virus. Smallpox causes fever and a blistering skin rash. These blisters contain virus and can make the infected person highly contagious.

Smallpox is spread from person to person through direct contact, or by coming into contact with infected bodily fluids or contaminated objects such as clothing or bedding. A person with early symptoms of smallpox may or may not be contagious. Once the person forms a smallpox skin rash, the chance of spreading the disease increases until the last smallpox scab has fallen off.

The smallpox vaccine is used to help prevent this disease. This vaccine works by exposing you to a small dose of the virus, which causes the body to develop immunity to the disease. This vaccine will not treat an active infection that has already developed in the body.

The smallpox vaccine contains live “vaccinia” virus (a virus similar to smallpox). For this reason, the vaccination site (the place on your skin where the vaccine is injected) will be contagious and can spread the virus to other parts of your body or to other people.

Like any vaccine, the smallpox vaccine may not provide protection from disease in every person.

The smallpox vaccine is not currently given as a routine vaccination because the dedicated use of smallpox vaccine in the first half of the 20th century has virtually eliminated the disease. The last case of smallpox in the United States occurred in 1949. The last reported case of smallpox worldwide occurred in 1977.

Recent concerns that smallpox virus might be used as a weapon of bioterrorism has led U.S. health officials to take precautions for a smallpox outbreak. The smallpox vaccine is currently recommended for military and civilian personnel who work in high-threat areas, and in healthcare and safety workers who may provide first-response care in an outbreak. Smallpox vaccine is also recommended for laboratory workers who may be exposed to the smallpox virus or closely related viruses.

You may not be able to receive this vaccine if you are pregnant, or if you have a weak immune system caused by disease (such as cancer, HIV, or AIDS) or by having a bone marrow transplant.

Some side effects of smallpox vaccine may lead to severe disability, permanent nerve damage, and/or death. Call your doctor at once or seek emergency medical attention if you have a severe headache, vision problems, flu symptoms, muscle weakness, chest pain, irregular heartbeats, swelling in your feet, changes in your mental status, or any sudden problems with hearing or speech.

Smallpox vaccine is a “live” vaccine, and the virus can “shed” from your injection site. Until the scab falls off, your vaccination sore will be contagious and could spread the virus to others for up to 21 days.Get medical help if someone in your household shows signs of smallpox: skin rash, fever, headache, body aches.

You should not receive this vaccine if you have ever had a life-threatening allergic reaction to any vaccine containing vaccinia virus.

Smallpox vaccine is not approved for use by anyone younger than 16 or older than 65 years old.

You may not be able to receive smallpox vaccine if you have severe immunosuppression (a weak immune system) or if you have had a bone marrow transplant. If you have a high risk of exposure to smallpox, you may need to receive the vaccine even if you have a weak immune system.

To make sure smallpox vaccine is safe for you, tell your doctor if you have:

  • a heart condition such as coronary artery disease, congestive heart failure, or chest pain (angina);
  • a history of heart attack, stroke, or “mini-stroke”;
  • at least 3 heart risk factors such as smoking, diabetes, high cholesterol, high blood pressure, or a family history of heart disease in a person younger than 50;
  • a weak immune system;
  • leukemia, lymphoma, or other types of cancer;
  • a skin disorder such as eczema (atopic dermatitis);
  • a skin wound, burn, infection such as impetigo or shingles (herpes zoster);
  • a condition for which you have recently used a steroid eye drop;
  • an allergy to neomycin or polymyxin B;
  • close contact with a pregnant woman, or anyone who has a weak immune system or a skin disorder such as eczema;
  • close contact with an infant younger than 12 months old;
  • if you are pregnant or breast-feeding; or
  • if you have recently received cancer chemotherapy or radiation treatment.

Using this vaccine during pregnancy could harm the unborn baby. However, if you are at a high risk for infection with smallpox during pregnancy, your doctor should determine whether you need this vaccine.

It is not known whether smallpox vaccine passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Frequently asked questions and answers on smallpox

Online Q&A
Updated 28 June 2016

What is smallpox?

Smallpox is an ancient disease caused by the variola virus. Early symptoms include high fever and fatigue. The virus then produces a characteristic rash, particularly on the face, arms and legs. The resulting spots become filled with clear fluid and later, pus, and then form a crust, which eventually dries up and falls off. Smallpox was fatal in up to 30% of cases.

Smallpox has existed for at least 3,000 years and was one of the world’s most feared diseases until it was eradicated by a collaborative global vaccination programme led by the World Health Organization. The last known natural case was in Somalia in 1977. Since then, the only known cases were caused by a laboratory accident in 1978 in Birmingham, England, which killed one person and caused a limited outbreak. Smallpox was officially declared eradicated in 1979.

Does it occur naturally?

Smallpox no longer occurs naturally since it was totally eradicated by a lengthy and painstaking process, which identified all cases and their contacts and ensured that they were all vaccinated. Until then, smallpox killed many millions of people.

How can I catch it and is it contagious?

The virus which causes smallpox is contagious and spreads through person-to- person contact and saliva droplets in an infected person’s breath. It has an incubation period of between 7 and 17 days after exposure and only becomes infectious once the fever develops. A distinctive rash appears two to three days later. The most infectious period is during the first week of illness, although a person with smallpox is still infectious until the last scabs fall off.

How fast does smallpox spread?

The speed of smallpox transmission is generally slower than for such diseases as measles or chickenpox. Patients spread smallpox primarily to household members and friends because by the time patients are contagious, they are usually sick and stay in bed; large outbreaks in schools were uncommon.

Weren’t the remaining stocks of the smallpox virus destroyed after smallpox was eradicated?

When smallpox was officially certified as eradicated, in December 1979, an agreement was reached under which all remaining stocks of the virus would either be destroyed or passed to one of two secure laboratories – one in the United States and one in the Russian Federation. That process was completed in the early 1980s and since then no other laboratory has officially had access to the virus which causes smallpox.

Then why is smallpox being talked about now?

Some governments believe there is a risk that the virus which causes smallpox exists in places other than these laboratories and could be deliberately released to cause harm. It is impossible to assess the risk that this might happen, but at their request, WHO is making efforts to help governments prepare for this possibility.

Can it be treated?

There is no cure for smallpox, but vaccination can be used very effectively to prevent infection from developing if given during a period of up to four days after a person has been exposed to the virus. This is the strategy that was used to eradicate the disease during the 20th century. New antiviral drugs, that have been developed for other diseases since smallpox was eradicated, may have a role. No studies of their usefulness, or safety, have been conducted on humans exposed to smallpox.

Is a vaccine currently available?

There is a vaccine against smallpox that was a key tool in the eradication of the disease. This vaccine does not contain the variola virus which causes smallpox, but a closely related virus called vaccinia. When this vaccine is given to humans, it protects them against smallpox. However, it may have rare, but serious side effects, which in extreme cases can be fatal. Since smallpox was eradicated, the vaccine is not recommended in routine immunization. It is used to protect researchers who work on the variola virus that causes smallpox and other viruses in the same virus family (known as orthopox viruses). It could also be used to protect anyone else judged to have a high risk of exposure to smallpox. The vaccine cannot be used in people who are immune depressed or immune suppressed.

After the eradication programme, a second generation of vaccines was developed that used the same smallpox vaccine strains as the vaccines used during the eradication campaign. A third generation of smallpox vaccines representing more attenuated vaccine strains, was specifically developed as safer vaccines for those high risk groups with immune disorders or dermatitis at the end of the eradication programme. However as these vaccines have not been used during the eradication campaign, the efficacy/effectiveness is not known.

Should the smallpox vaccine be widely used to protect people?

Vaccination with the vaccinia virus as a protection against smallpox is not recommended for widespread use. No government gives or recommends the vaccine routinely since it can cause serious complications, and even death. It should be given only to those persons who have a high risk of coming into contact with the virus which causes smallpox, or who have been exposed.

What can be done to protect people from smallpox?

Doctors, health workers and hospital personnel around the world have been trained to identify infectious diseases, verify their diagnosis and then respond accordingly. The same system would identify any possible outbreak of smallpox even if the virus is deliberately spread to cause harm. The public health system would then be mobilized to trace all known contacts of the infected person and vaccinate them to prevent more cases of smallpox from developing. If this is done rapidly and effectively, the number of cases could be kept to a minimum and the outbreak would be contained. This was the approach which successfully eradicated the disease. Key is to have a good disease detection system in place as well as a rapid response to infectious diseases, no matter what their cause. Several governments have examined the potency and levels of their smallpox vaccine stocks, and to consider whether, and under what circumstances, to obtain additional supplies.

I had the vaccination when I was a child. Am I still protected?

Anyone who has been vaccinated against smallpox (in most countries, this means anyone aged 40 or over) will have some level of protection. The vaccination may not still be fully effective, but it is likely to protect you from the worst effects of the disease. However, if you were directly exposed to the virus which causes smallpox, a repeat vaccination would be recommended.

What is WHO doing now?

WHO coordinates various preparedness and response activities to protect global health from any possible outbreak of smallpox. WHO receives information from governments and other sources on unusual disease outbreaks. It provides technical guidance to help countries respond to these events. WHO has displayed practical information on smallpox diagnosis, surveillance, and outbreak response on its web site. It can help countries identify potential sources of vaccine, should such a need arise.

Household Transmission of Vaccinia Virus from Contact with a
Military Smallpox Vaccinee — Illinois and Indiana, 2007

Persons using assistive technology might not be able to fully access information in this file. For assistance, please send e-mail to: [email protected] Type 508 Accommodation and the title of the report in the subject line of e-mail.

On March 7, 2007, the Chicago Department of Public Health and the University of Chicago Pediatric Infectious Disease Service and Infection Control Program notified CDC of a child with presumed eczema vaccinatum (EV), a life-threatening complication of vaccinia virus infection (1). This is the first reported EV case in the United States since 1988 (2). This report summarizes the epidemiologic and environmental investigations conducted by local, state, and federal public health authorities in Illinois and Indiana to determine the source of exposure and to identify and monitor other persons at risk for vaccinia virus infection. This case highlights the need for clinicians to maintain a high index of suspicion when evaluating recently vaccinated patients and their family members with vesiculopustular rash.

On January 26, 2007, an active-duty U.S. service member received a first-time smallpox vaccination in preparation for overseas military deployment. He had a history of childhood atopic dermatitis (i.e., eczema) and household contact with persons with eczema (two of his three children), both of which are contraindications to vaccination. His deployment was delayed, so he made an unplanned visit home to visit his family in Indiana during February 16–20. During this period, he spent time with his son, aged 28 months, who has severe eczema and a history of failure to thrive. The father reported his vaccination site had scabbed over and that the scab had separated before the visit home; he also reported that he kept the site bandaged during the visit. His routine activities with his son included hugging, wrestling, sleeping, and bathing.

On March 3, the child was taken to a small, local Indiana hospital because of a generalized papular, vesicular rash on the face, neck, and upper extremities. Because of the severity of the illness, he was transferred to a tertiary-care facility in Chicago later that day; contact precautions were implemented at the hospital. The child’s mother indicated that the boy had a fever 2 days before his hospital admission and weeping skin lesions as early as February 24. By March 7, the rash had progressed to umbilicated lesions with an erythematous base, primarily involving the child’s hands, forearms, neck, chest, face, and knees and encompassing 50% of his keratinized skin (Figure). On March 8, lesion specimens were analyzed at the Illinois Department of Public Health Laboratory (IDPHL) in Chicago by real-time polymerase chain reaction (PCR) orthopoxvirus generic assay and nonvariola orthopoxvirus assay. The results of the assays were positive for orthopoxvirus DNA, supporting the clinical diagnosis of EV. The diagnosis of vaccinia was confirmed at CDC.

During March 8–28, the child was treated with a combination of immunotherapy and antivirals targeting vaccinia virus. The initial treatment included Vaccinia Immune Globulin Intravenous (Human) (VIGIV); supportive care included sedation, intubation, and mechanical ventilation. Despite these interventions, on March 10, the child’s illness had progressed to hypothermia and hemodynamic instability requiring vasopressor support. Antiviral therapies with cidofovir and an investigational drug, ST-246 (SIGA Technologies, Corvallis, Oregon) under an Emergency Investigational Drug application, were initiated sequentially,* and additional infusions of VIGIV were administered. After approximately 1 week of interventions, the child began to improve. On April 19, the child was discharged home after 48 days of hospitalization; he has no known sequelae other than possible scarring of the skin.

Clinical specimens (e.g., lesion material, blood, and serum) collected during the patient’s hospitalization were analyzed in the CDC Poxvirus Laboratory. All specimens collected during the first 10 days of his hospitalization were positive for orthopoxvirus DNA using a real-time PCR assay. Before VIGIV administration, serum was positive for antiorthopoxvirus immunoglobulin M (IgM) and negative for immunoglobulin G (IgG) by enzyme-linked immunosorbent assay.

On March 6, the child’s third hospital day, hospital staff members noticed that the patient’s mother had approximately six vesicular lesions on her face; additional lesions subsequently developed on her right index finger and near her eyelid. The mother had a history of facial acne flare-ups and reported that she had rested her cheek on the child’s abdomen while he was being treated in the hospital. Lesion material was analyzed by IDPHL and found to contain orthopoxvirus DNA signatures. The mother was isolated voluntarily in the same room as her son; on March 10, she received VIGIV treatment. Within 72 hours of the initiation of VIGIV treatment, her lesions began to scab over. Evaluation of serum collected from the mother on March 8 indicated that she had not yet developed an antiorthopoxvirus humoral immune response (IgG and IgM negative).

The couple has two other children, one with a history of eczema. Both children left the family residence at the time of the child’s hospitalization and were cared for by their grandparents. Neither child had symptoms of vaccinia infection at the time of this report.

Public health and infection-control professionals interviewed community contacts, family members, and hospital staff members to identify persons who might have had physical contact (i.e., skin-to-skin) with the ill child after February 23 (the day before the child’s first possible skin eruption) or the father while he was home on leave during February 16–20. Twenty-three family contacts, including the two siblings, and 73 health-care worker contacts were identified. Persons were monitored daily for the onset of contact vaccinia symptoms for 21 days after their last potential vaccinia exposure. During this period, one person had a rash, and one had fever; neither person had vaccinia virus infection. All other potential contacts remained healthy throughout the follow-up period; no nosocomial transmission occurred. Hospital and public health officials recommended that the mother and child remain isolated until they had no more vaccinia scabs.

Because the child had a rash before being hospitalized, an environmental assessment of the family home was conducted on March 13 to determine whether viable vaccinia virus was still present. Multiple swab samples obtained from the home (e.g., from a bathroom washcloth, a slipper, a toy drum, a night stand, a booster seat, and an ointment container) and from items brought to the child’s hospital room (e.g., an infant drinking cup and a car seat) were positive for vaccinia virus DNA by real-time PCR assay. Cell culture of samples collected from three of these items (booster seat, toy drum, and slipper) contained viable virus. Disinfection procedures were completed on March 23 and included steam cleaning of carpeted areas, disinfection of household surfaces with phenolics, and hot washing of clothing and linens after a phenolic presoak.

Editorial Note:

This report describes the first documented case of EV in the United States since 1988 (2). The epidemiologic investigation and clinical history indicated that secondary transmission of vaccinia virus occurred between the father and child. The stage of healing of the father’s vaccination site during the exposure period was reported by the father and was not clinically confirmed, nor was consistent use of a bandage. Serologic evidence and clinical history further suggests that tertiary transmission might have occurred between the child and mother. In addition, the possibility of transmission by fomites (i.e., contaminated objects such as toys and towels) cannot be excluded; the targeted environmental assessment detected infectious virus more than 1 week after the ill child had left the home.

The World Health Organization declared smallpox eradicated in 1979. However, smallpox vaccination was required for U.S. military personnel until 1990, when it was discontinued. After the September 11, 2001, terrorist attacks and the 2001 anthrax cases, the U.S. government reinstated smallpox vaccination for military personnel and selected health-care workers. The U.S. Department of Defense had vaccinated approximately 1.2 million persons as of March 2007.†

The smallpox vaccine contains live vaccinia virus, which confers protection against infection from variola virus, the cause of smallpox. Vaccinia virus can be transmitted from a vaccine recipient to other persons through direct (skin-to-skin) contact via material from the unhealed vaccination site or through indirect contact by means of fomites (4–6). Vaccinia virus can be cultured from the site of primary vaccination beginning at the time of development of a papule (i.e., 2–5 days after vaccination). Generally, a scab forms at the vaccination site by day 14 and falls off by day 21 (7). Until the vaccination scab falls off, a person who has been vaccinated can transmit vaccinia virus to others. Persons who are infected through contact with a person who has received smallpox vaccination are at risk for the same adverse reactions to smallpox vaccination as the vaccine recipient.

EV is a rare but serious reaction to smallpox vaccine. A history of eczema, atopic dermatitis (regardless of disease severity or activity), or Darier’s disease is a risk factor for EV, both for vaccine recipients and their close contacts; having household contacts with any of these conditions also is a contraindication Although no data exist to predict the risk for EV among such persons, before 1990, the incidence rate for EV after smallpox vaccination was approximately eight to 80 cases per 1 million vaccinations (8). The introduction of intramuscularly administered vaccinia immune globulin treatment was estimated to have reduced EV-associated mortality from 30%–40% to 7% (9). Licensed in 2005, VIGIV is the only product available that is approved by the Food and Drug Administration for treating patients with EV (8).

Consistent with current Advisory Committee on Immunization Practices guidelines to prevent transmission of vaccinia from vaccinated persons to close personal contacts, persons who have been vaccinated should wear long-sleeved clothing and cover the vaccination site with gauze or a similar semipermeable dressing until the scab separates from the skin independently (i.e., without assistance from the person) (3). Vaccinated persons should not share towels or clothing with others and should wash their hands with warm, soapy water or a hand-rub solution containing >60% alcohol immediately after they touch their vaccination site or change their vaccination-site bandages (3). Contraindications to smallpox vaccination should be considered before the administration of vaccine; these include pregnancy, immune-compromising conditions (e.g., human immunodeficiency virus infection), or a chronic skin disease such as eczema. Having household contacts with any of these conditions also is a contraindication. Agencies whose health-care providers administer smallpox vaccine should periodically assess the effectiveness of vaccine-related education for these providers and for the vaccine recipients.

The administration of smallpox vaccine to this service member and his subsequent contact with his family are under investigation by the U.S. military, which will determine whether screening and education practices need to be modified (10). Health-care workers treating patients with EV, generalized vaccinia infection, or progressive vaccinia infection should follow contact precautions until patients’ scabs have separated. Clinicians should maintain a high index of suspicion for vaccinia when evaluating vesiculopapular rashes in patients who have been vaccinated recently and in their close contacts. Suspected cases of vaccinia should be reported to state or local health departments and to the Vaccine Adverse Events Reporting System online ( or by telephone (800-822-7967). Laboratories that are part of the Laboratory Response Network (LRN) ( have the ability to assess clinical specimens for the presence of orthopoxvirus DNA signatures. Specimens from the LRN can be forwarded to the CDC Poxvirus Laboratory for species confirmation.

* Cidofovir is administered as a weekly dose as clinically indicated and reserved as second-line therapy after VIGIV in the treatment of eczema vaccinatum (3). ST-246 is a smallpox drug candidate with specific antiorthopoxvirus activity inhibiting virus maturation.

† US Army Center for Health Promotion and Preventive Medicine. Defense manpower data center statistical immunization reporting system; 2007.


Return to top.

Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.

Disclaimer All MMWR HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

**Questions or messages regarding errors in formatting should be addressed to [email protected]

Date last reviewed: 5/17/2007

Smallpox is a serious, highly contagious, and sometimes fatal infectious disease. There is no specific treatment for smallpox disease, and the only prevention is vaccination. The name is derived from the Latin word for “spotted” and refers to the raised bumps that appear on the face and body of an infected person. Two clinical forms of smallpox have been described. Variola major is the severe form of smallpox, with a more extensive rash and higher fever. It is also the most common form of smallpox. There are four types of variola major smallpox: ordinary (the most frequent); modified (mild and occurring in previously vaccinated persons); flat; and hemorrhagic. Historically, variola major has a case-fatality rate of about 30%. However, flat and hemorrhagic smallpox, which are uncommon types of smallpox, are usually fatal. Hemorrhagic smallpox has a much shorter incubation period and is likely not to be initially recognized as smallpox when presenting to medical care. Smallpox vaccination also does not provide much protection, if any, against hemorrhagic smallpox. Variola minor is a less common clinical presentation, and much less severe disease (for example, historically, death rates from variola minor are 1% or less).

Variola virus is the etiological agent of smallpox. During the smallpox era, the only known reservoir for the virus was humans; no known animal or insect reservoirs or vectors existed. The most frequent mode of transmission was person-to-person, spread through direct deposit of infective droplets onto the nasal, oral, or pharyngeal mucosal membranes, or the alveoli of the lungs from close, face-to-face contact with an infectious person. Indirect spread (i.e., not requiring face-to-face contact with an infectious person) through fine-particle aerosols or a fomite containing the virus was less common.

Symptoms of smallpox begin 12–14 days (range: 7–17) after exposure, starting with a 2–3 day prodrome of high fever, malaise, and prostration with severe headache and backache. This preeruptive stage is followed by the appearance of a maculopapular rash (i.e., eruptive stage) that progresses to papules 1–2 days after the rash appears; vesicles appear on the fourth or fifth day; pustules appear by the seventh day; and scab lesions appear on the fourteenth day. The rash appears first on the oral mucosa, face, and forearms, then spreads to the trunk and legs. Lesions might erupt on the palms and soles as well. Smallpox skin lesions are deeply embedded in the dermis and feel like firm round objects embedded in the skin. As the skin lesions heal, the scabs separate and pitted scarring gradually develops. Smallpox patients are most infectious during the first week of the rash when the oral mucosa lesions ulcerate and release substantial amounts of virus into the saliva. A patient is no longer infectious after all scabs have separated (i.e., 3–4 weeks after the onset of the rash).

Dryvax, a smallpox vaccine, originally licensed in 1944 to Wyeth Laboratories, Inc. of Madison, N.J., was manufactured until the mid 1980s when the World Health Organization declared that smallpox had been eradicated. Currently there is one licensed smallpox vaccine; ACAM2000, licensed on August 31, 2007, which is manufactured by Sanofi Pasteur Biologics Co. of Cambridge, MA and is based on the same strain of virus as Dryvax. ACAM2000 is indicated for active immunization against smallpox disease for persons determined to be at high risk for smallpox infection. ACAM2000 is administered by scarification to the deltoid muscle or the posterior aspect of the arm over the triceps muscle.

On May 2, 2005, CBER licensed Vaccinia Immune Globulin, Intravenous (VIGIV) manufactured by Cangene Corporation of Winnepeg, Manitoba, Canada. VIGIV, is used to treat rare serious complications of smallpox vaccination.

Smallpox Vaccine Background Information

  • Smallpox (Vaccinia) Vaccine, Live (ACAM2000)
  • ACAM2000 (Smallpox Vaccine) Questions and Answers
  • Vaccinia Immune Globulin Intravenous (Human)

Resources For You

  • Countering Bioterrorism and Emerging Infectious Diseases

Smallpox vaccine Side Effects

Medically reviewed by Last updated on Feb 19, 2019.

  • Overview
  • Side Effects
  • Dosage
  • Interactions
  • Pregnancy
  • More

Applies to smallpox vaccine: percutaneous powder for injection


Regional lymphadenopathy, myalgia, fever, nausea, and malaise occur at the height of the major reaction after vaccination, indicating the vaccination was successful. Fever commonly occurs in children after vaccination but is less common in adults. From 4 to 14 days after primary vaccination at least 70% of children have had 1 or more days of temperature greater than 100 degrees F. Fifteen to twenty percent have had temperatures greater than 102 degrees F.


The most frequent complication is inadvertent inoculation of other sites, usually due of autoinoculation of the virus transferred from the vaccination site to other parts of the body. The face, eyelids, nose, mouth, genitalia, and rectum are most commonly involved. Autoinoculation of the eyes may cause blindness.

Postvaccinial encephalitis, encephalomyelitis, encephalopathy, progressive vaccinia (vaccinia necrosum) and eczema vaccinatum are more severe complications that may occur following primary vaccination or revaccination. Severe disability, permanent neurological sequelae, and/or death may occur. Approximately 1 death per million primary vaccinations and 1 death per 4 million revaccinations have been reported, most often due to encephalitis or progressive vaccinia. Death has also occurred in unvaccinated contacts of vaccinated persons. Vaccinia viremia has been rarely reported after vaccination.

Vaccinia Immune Globulin may be indicated for certain vaccine complications such as eczema vaccinatum, progressive vaccinia, severe generalized vaccinia, or severe ocular vaccinia and may be obtained from the Centers for Disease Control (CDC). Physicians may contact the CDC for assistance with diagnosis and treatment of smallpox vaccine complications. Telephone: (404) 639-3670 (Monday-Friday, 8 AM-4:30 PM EST) or (404) 639-2888 (at other times).


Healthy persons may develop generalized vaccinia with a generally self-limited vesicular or maculopapular rash within 6 to 9 days after vaccination. This condition is more serious in immunocompromised individuals.

Eczema vaccinatum appears shortly after the vaccinial lesion appears and is characterized by a high fever, malaise, generalized lymphadenopathy, and extensive vesicular and pustular eruptions. Patients with a history of atopic dermatitis have the highest risk of developing EV. The prognosis is poor and the mortality rate is high.

Progressive vaccinia (i.e., vaccinia necrosum, vaccinia gangrenosa, prolonged vaccinia, disseminated vaccinia), is characterized by a nonhealing vaccination site, painless progressive necrosis at the vaccination site, and occasionally metastasis to other parts of the skin, bones, and viscera. The distant lesions contain live vaccinia virus. Immunocompromised patients are at a greater risk. The prognosis is poor.

Vaccinia Immune Globulin (VIG) may be indicated for eczema vaccinatum or progressive vaccinia and may be obtained from the Centers for Disease Control (CDC). Physicians may contact the CDC for assistance with diagnosis and treatment of smallpox vaccine complications. Telephone: (404) 639-3670 (Monday-Friday, 8 AM-4:30 PM EST) or (404) 639-2888 (at other times).

Hypersensitivity reactions including Stevens-Johnson syndrome and erythema multiforme have rarely been reported. The onset of symptoms (bulls-eye lesions and pruritus) is generally 10 days after vaccination.

Dermatofibrosarcoma protuberans, malignant fibrous histiocytoma, malignant melanoma, squamous cell carcinoma, basal cell carcinoma, and benign dermatofibroma have been reported in smallpox vaccination scars.

Contact spread of vaccinia from recently vaccinated military personnel has been reported.

Dermatologic side effects have included pruritus, rash, generalized vaccinia (GV), eczema vaccinatum (EV), progressive vaccinia (PV), erythema multiforme, folliculitis, Stevens-Johnson syndrome, bacterial infections, and contact spread. In addition, precipitation of erythema nodosum in patients with leprosy, malignant tumors at the vaccination scar, discoid lupus, and localized myxedema have been reported; however, causality has not been established.


Local side effects have included secondary pyogenic infections at the site of vaccine application. occurring approximately 5 days after vaccination. Swelling, warmth, and pain at the injection site, with peak symptoms occurring 8 to 10 days after vaccination and resolving within 24 to 72 hours, are indicative of a normal vaccination reaction.


Hypersensitivity reactions may include persistent allergic sensitization to viral proteins even after immunity has waned. The allergy is manifested by the appearance of a papule and a small area of redness appearing within the first 24 hours after revaccination. Vesicles may appear in 24 to 48 hours, followed by scabbing. Stevens-Johnson syndrome, and erythema multiforme have also been reported.


Ocular side effects have included mild to severe ocular vaccinia resulting from inadvertent autoinoculation and manifested by keratitis (epithelial and stromal), iritis, conjunctivitis (hyperemia, edema, membranes, focal lesions), and/or blepharitis (lid pustules, edema, hyperemia, cellulitis). Corneal scarring, disciform edema, and loss of vision have occurred in patients with vaccinial keratitis. Lymphadenopathy and fever have also been associated with ocular vaccinia. Ocular vaccinia has been reported in contacts of vaccinees.

Trifluridine or vidarabine ophthalmic ointment have been recommended for conjunctival or corneal vaccinia infections. In addition, vaccinia immune globulin (VIG) may be considered for severe blepharitis, blepharoconjunctivitis, or keratitis (if there is a risk of vision loss). When using of VIG for keratitis, the possibility of an increased risk of corneal scar formation (associated with large doses over multiple days in animal models) should be taken into consideration. VIG is not recommended for isolated keratitis.

Nervous system

Nervous system side effects have rarely included headache, dizziness, paresthesia, vertigo, transient global amnesia, anoxic encephalopathy, polyneuropathy, cerebrovascular accident, CNS tumor, precipitation of neuritis in leprosy patients, transverse myelitis, seizures, paralysis, polyneuritis, brachial neuritis, and one case of ptosis, diplopia, slurred speech, and paresis, although causality has not been clearly established in all cases. The vaccine has also been associated with encephalitis (PVE) and encephalomyelitis (PVEM). PVE is has a sudden onset (6 to 10 days after vaccination) and is characterized by seizures, hemiplegia, aphasia, transient amnesia, generalized cerebral edema, mild lymphocytic meningeal infiltration, ganglion degenerative changes, and perivascular hemorrhages. Cerebrospinal fluid examination may demonstrate increased opening CSF pressure, monocytosis, lymphocytosis, or elevated CSF protein. PVEM is characterized by sudden onset (11 to 15 days after vaccination) of fever, headache, malaise, lethargy, vomiting, and anorexia. Symptoms may progress to unconsciousness, amnesia, confusion, disorientation, restlessness, delirium, drowsiness, seizures, urinary incontinence, urinary retention, constipation, meningismus and/or coma. Increased CSF pressure is present, but chemistry and cell count may be normal. Histopathological changes include perivenous demyelination, microglial proliferation in demyelinated areas with lymphocytic infiltration.

PVE occurs more commonly in children less than 2 years old. The incidence in 1968 was reported as 2.9 cases per million vaccinees. The mortality rate is 25%, complete recovery occurs in 50%, and neurologic sequelae remain in 25%.


Cardiovascular side effects have rarely included myocarditis, pericarditis, myocardial infarction, hypertension, atypical chest pain, angina, palpitations, supraventricular tachycardia, atrial dysrhythmias, symptomatic trigeminy, premature ventricular contractions, coronary artery disease, dilated cardiomyopathy, sudden death due to atherosclerotic coronary artery disease 60 days after vaccination, and chest tightness with ECG changes, although causality has not been clearly established in all cases.

Symptoms of myopericarditis include chest pain, ECG changes, increased cardiac enzymes, and sometimes abnormal echocardiograms, and usually occur 4 to 30 days after vaccination.

Pulmonary edema and eosinophilic myopericarditis developed in a 29-year-old male 3 weeks after multiple vaccinations including smallpox vaccine.


Musculoskeletal side effects have included osteomyelitis, arthritis, shoulder pain, and noncardiac chest pain; however, causality has not been established in all cases.


Respiratory side effects have rarely included asthma, pneumonia, respiratory distress, and pseudomediastinum associated with scuba diving, although causality has not been clearly established.


Genitourinary side effects have rarely included prostatitis, although causality has not been clearly established.


Gastrointestinal side effects have rarely included cholecystitis and gastroesophageal reflux disease, although causality has not been clearly established in all cases.

1. “Smallpox vaccination and adverse reactions: guidance for clinicians.” MMWR Morb Mortal Wkly Rep 52 (2003): 1-29

5. “Smallpox vaccine adverse events among civilians–United States, March 4-10, 2003.” MMWR Morb Mortal Wkly Rep 52 (2003): 201-3

6. “Product Information. Dryvax (smallpox vaccine).” Wyeth-Ayerst Laboratories, Philadelphia, PA.

8. Grabenstein JD, Winkenwerder W Jr “US Military Smallpox Vaccination Program Experience.” JAMA 289 (2003): 3278-82

10. Bray M, Wright ME “Progressive vaccinia.” Clin Infect Dis 36 (2003): 766-74

14. Talbot TR, Bredenberg HK, Smith M, LaFleur BJ, Boyd A, Edwards KM “Focal and generalized folliculitis following smallpox vaccination among vaccinia-naive recipients.” JAMA 289 (2003): 3290-4

16. Green JJ, Heymann WR “Dermatofibrosarcoma protuberans occurring in a smallpox vaccination scar.” J Am Acad Dermatol 48(5 Suppl) (2003): S54-5

23. “Update: cardiac and other adverse events following civilian smallpox vaccination–United States, 2003.” MMWR Morb Mortal Wkly Rep 52 (2003): 639-42

24. “Update: adverse events following smallpox vaccination–United States, 2003.” MMWR Morb Mortal Wkly Rep 52 (2003): 278-82

25. Vastag B “Experts weigh prevention, therapy for ocular vaccinia in smallpox vaccinees.” JAMA 289 (2003): 2198-9

26. Hu G, Wang MJ, Miller MJ, et al. “Ocular vaccinia following exposure to a smallpox vaccinee.” Am J Ophthalmol 137 (2004): 554-6

27. “Cardiac deaths after a mass smallpox vaccination campaign–New York City, 1947.” MMWR Morb Mortal Wkly Rep 52 (2003): 933-6

28. “Supplemental Recommendations on Adverse Events Following Smallpox Vaccine in the Pre-Event Vaccination Program: Recommendations of the Advisory Committee on Immunization Practices.” JAMA 289 (2003): 2064

32. “Supplemental recommendations on adverse events following smallpox vaccine in the pre-event vaccination program: recommendations of the Advisory Committee on Immunization Practices.” MMWR Morb Mortal Wkly Rep 52 (2003): 282-4

34. Whitman TJ, Ferguson MA, Decker CF “Cardiac dysrhythmia following smallpox vaccination.” Clin Infect Dis 37 (2003): 1579-80

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer

More about smallpox vaccine

  • During Pregnancy or Breastfeeding
  • Dosage Information
  • Drug Interactions
  • Drug class: viral vaccines

Consumer resources

  • Smallpox vaccine Injection (Advanced Reading)

Other brands: Dryvax, ACAM2000

Related treatment guides

  • Smallpox Prophylaxis

Source: Reuters, March 3, 2003

Patient OK After Smallpox Shot-Linked Eye Infection

By Keith Mulvihill

NEW YORK (Reuters Health) – A Los Angeles patient who developed an eye infection with the virus found in the smallpox vaccine was a close contact of a recently vaccinated individual who is in the military, according to the Los Angeles County Department of Health Services.

The infection with the vaccinia virus was not life threatening and is not surprising, according to Dr. Jonathan Fielding, director of public health in the department.

While it is not known exactly how long the adult patient, who has not been identified, has been infected, Fielding told Reuters Health that sometime during the third week of February the person started to show symptoms and was hospitalized around the 21st of February.

“I don’t even know if the person is still in the hospital, I haven’t checked yet today,” he said during a telephone interview Monday.

Nonetheless, the person was “getting better and that is what is most important…the infection was not life threatening,” added Fielding.

After being admitted to the hospital, doctors learned that the individual had “close contact” with a member of the military who had recently been vaccinated with the smallpox vaccine.

Extensive testing reveled that the individual was infected with vaccinia, the live virus related to smallpox used in the current smallpox vaccine.

According to Fielding, the patient’s symptoms were marked by conjunctivitis, which is evidence of an infection in the eye. The person, whose age or gender has not been released, experienced excessive tearing of the eye, swelling near and around the eye and “visual disturbances,” noted Fielding.

“The prognosis is good,” he added. “The individual has been improving after receiving anti-viral drops.”

So far, Fielding’s team is not exactly sure how the person became infected.

“We don’t know exactly if the person contracted the infection from touching the vaccination site or a towel used by the vaccinee, these are all hypothesis, we don’t know exactly how it happened,” he said.

It is not clear if the individual had a weak immune system or another condition that might have made him or her more vulnerable to infection, Fielding noted.

Still, the current case should not be cause for alarm, he added.

Based on data from 1960s when the vaccine was given routinely, transmission and infection with the vaccinia virus through close contact occurred in 2 to 6 people per 100,000 people who received the vaccine, according to Fielding.

“So this (new case) is not surprising,” he added.

There is no treatment for smallpox, which kills about one third of those infected. The disease begins with flu-like symptoms, followed by a rash, then pus-filled lesions on the face and body. Vaccination within a few days of exposure to the virus can prevent disease or reduce symptoms.

However, the smallpox vaccine itself carries risks. When smallpox vaccination was routine, about 1,000 people per million had significant side effects such as an allergic reaction at the site of vaccination or spread of the vaccinia virus to other parts of the body.

And for every million people vaccinated, one or two may die, according to the US Centers for Disease Control and Prevention.



Included as part of the PRECAUTIONS section.


Persons at greatest risk of experiencing serious vaccination complications are often those at greatest risk for death from smallpox. The risk for experiencing serious vaccination complications must be weighed against the risks for experiencing a potentially fatal smallpox infection.

Serious Complications And Death

Serious complications that may follow either primary live vaccinia smallpox vaccination or revaccination include: myocarditis and/or pericarditis, encephalitis, encephalomyelitis, encephalopathy, progressive vaccinia (vaccinia necrosum), generalized vaccinia, severe vaccinial skin infections, erythema multiforme major (including Stevens-Johnson syndrome), eczema vaccinatum, blindness, and fetal death in pregnant women. These complications may rarely lead to severe disability, permanent neurological sequelea and death. Based on clinical trials, symptoms of suspected myocarditis or pericarditis (such as chest pain, raised troponin/cardiac enzymes, or ECG abnormalities) occur in 5.7 per 1000 primary vaccinations. This finding includes cases of acute symptomatic or asymptomatic myocarditis or pericarditits or both. Historically, death following vaccination with live vaccinia virus is a rare event; approximately 1 death per million primary vaccinations and 1 death per 4 million revaccinations have occurred after vaccination with live vaccinia virus. Death is most often the result of sudden cardiac death, postvaccinial encephalitis, progressive vaccinia, or eczema vaccinatum. Death has also been reported in unvaccinated contacts accidentally infected by individuals who have been vaccinated.

Incidence Of Serious Complications In 1968 US Surveillance Studies

Estimates of the risks of occurrence of serious complications after primary vaccination and revaccination, based on safety surveillance studies conducted when live vaccinia virus smallpox vaccine (i.e., New York City Board of Health strain, Dryvax®) was routinely recommended, are as follows:

Table 1A : Rates of reported complicationsa associated with primary vaccinia vaccinations (cases/million vaccinations)b

Age (yrs) < 1 1-4 5-19 ≥ 20 Overall ratesh
Inadvertent inoculationc § 507.0 577.3 371.2 606.1 529.2
Generalized vaccinia 394.4 233.4 139.7 212.1 241.5
Eczema vaccinatum 14.1 44.2 34.9 30.3 38.5
Progressive vacciniad –g 3.2 –g –g 1.5
Post-vaccinial encephalitis 42.3 9.5 8.7 –g 12.3
Deathe 5 0.5 0.5 unknown
Totalf 1549.3 1261.8 855.9 1515.2 1253.8
a See article for descriptions of complications.
b Adapted from Lane JM, Ruber FL, Neff JM, Millar JD. Complications of smallpox vaccination, 1968: results of ten statewide surveys. J Infect Dis. 1970; 122:303-309.
c Referenced as accidental implantation.
d Referenced as vaccinia necrosum.
e Death from all complications.
f Rates of overall complications by age group include complications not provided in this table, including severe local reactions, bacterial superinfection of the vaccination site, and erythema multiforme.
g No instances of this complication were identified during the 1968 10-state survey.
h Overall rates for each complication include persons of unknown age.

Table 1B : Rates of reported serious complicationsa associated with vaccinia revaccinations (cases/million vaccinations)b

Incidence Of Serious Complications And Emergence Of Myocarditis And/Or Pericarditis In 2002-2005

Data on the incidence of adverse events among U.S. military personnel and civilian first responders vaccinated with Dryvax®, a licensed live vaccinia virus smallpox vaccine, during vaccination programs initiated in December 2002 are shown below in Table 2. The incidence of preventable adverse events (eczema vaccinatum, contact transmission, and auto-inoculation) were notably lower in these programs when compared with data collected in the 1960s; presumably because of better vaccination screening procedures and routine use of protective bandages over the inoculation site. Myocarditis and pericarditis were not commonly reported following smallpox vaccination in the 1960s, but emerged as a more frequent event based on more active surveillance in the military and civilian programs.

Table 2 : Serious adverse events in 2002-20055

Adverse event Department of Defense program (n=730,580a) as of Jan05 Department of Health and Human Services program (n=40, 422) as of Jan04b
N Incidence/ million N Incidence /million
Myo/pericarditis Post-vaccinal 86 117.71 21 519.52
encephalitis 1 1.37 1 24.74
Eczema vaccinatum 0 0.00 0 0.00
Generalized vaccinia 43 58.86 3 74.22
Progressive vaccinia 0 0.00 0 0.00
Fetal vaccinia 0 0.00 0 0.00
Contact transmission 52 71.18 0 0.00
Auto-inoculation (nonocular) 62 84.86 20 494.78
Ocular vaccinia 16 21.90 3 74.22
a 71% primary vaccination; 89% male; median age 28.5 yr
b 36% primary vaccination; 36% male; median age 47.1 yr

Myocarditis And Pericarditis In The ACAM2000 Clinical Trial Experience

In clinical trials involving 2983 subjects who received ACAM2000 and 868 subjects who received Dryvax®, ten (10) cases of suspected myocarditis were identified. The mean time to onset of suspected myocarditis and/or pericarditis from vaccination was 11 days, with a range of 9 to 20 days. All subjects who experienced these cardiac events were naïve to vaccinia. Of the 10 subjects, 2 were hospitalized. None of the remaining 8 cases required hospitalization or treatment with medication. Of the 10 cases, 8 were sub-clinical and were detected only by ECG abnormalities with or without associated elevations of cardiac troponin I. All cases resolved by 9 months, with the exception of one female subject in the Dryvax® group, who had persistent borderline abnormal left ventricular ejection fraction on echocardiogram. The best estimate of risk for myocarditis and pericarditis is derived from the Phase 3 ACAM2000 clinical trials where there was active monitoring for potential of myocarditis and pericarditis. Among vaccinees naïve to vaccinia, 8 cases of suspected myocarditis and pericarditis were identified across both treatment groups, for a total incidence rate of 6.9 per 1000 vaccinees (8 of 1,162). The rate for the ACAM2000 treatment group were similar: 5.7 (95% CI: 1.9-13.3) per 1000 vaccinees (5 of 873 vaccinees) and for the Dryvax® group 10.4 (95% CI: 2.1-30.0) per 1000 vaccinees (3 of 289 vaccinees). No cases of myocarditis and/or pericarditis were identified in 1819 previously vaccinated subjects. The long-term outcome of myocarditis and pericarditis following ACAM2000 vaccination is currently unknown.

Cardiac Disease

Ischemic cardiac events, including fatalities, have been reported following smallpox vaccination; the relationship of these events, if any, to vaccination has not been established. In addition, cases of non-ischemic, dilated cardiomyopathy have been reported following smallpox vaccination; the relationship of these cases to smallpox vaccination is unknown.

There may be increased risks of adverse events with ACAM2000 in persons with known cardiac disease, including those diagnosed with previous myocardial infarction, angina, congestive heart failure, cardiomyopathy, chest pain or shortness of breath with activity, stroke or transient ischemic attack, or other heart conditions. In addition, subjects who have been diagnosed with 3 or more of the following risk factors for ischemic coronary disease: 1) high blood pressure; 2) elevated blood cholesterol; 3) diabetes mellitus or high blood sugar; 4) first degree relative (for example mother, father, brother, or sister) who had a heart condition before the age of 50; or 5) smoke cigarettes may have increased risks.

Ocular Complications And Blindness

Accidental infection of the eye (ocular vaccinia) may result in ocular complications including keratitis, corneal scarring and blindness. Patients who are using corticosteroid eye drops may be at increased risk of ocular complications with ACAM2000.

Presence Of Congenital Or Acquired Immune Deficiency Disorders

Severe localized or systemic infection with vaccinia (progressive vaccinia) may occur in persons with weakened immune systems, including patients with leukemia, lymphoma, organ transplantation, generalized malignancy, HIV/AIDS, cellular or humoral immune deficiency, radiation therapy, or treatment with antimetabolites, alkylating agents, or high-dose corticosteroids ( > 10 mg prednisone/day or equivalent for ≥ 2 weeks). The vaccine is contraindicated in individuals with severe immunodeficiency . Vaccinees with close contacts who have these conditions may be at increased risk because live vaccinia virus can be shed and be transmitted to close contacts.

History Or Presence Of Eczema And Other Skin Conditions

Persons with eczema of any description such as, atopic dermatitis, neurodermatitis, and other eczematous conditions, regardless of severity of the condition, or persons who have a history of these conditions at any time in the past, are at higher risk of developing eczema vaccinatum. Vaccinees with close contacts who have eczematous conditions, may be at increased risk because live vaccinia virus can shed and be transmitted to these close contacts. Vaccinees with other active acute, chronic or exfoliative skin disorders (including burns, impetigo, varicella zoster, acne vulgaris with open lesions, Darier’s disease, psoriasis, seborrheic dermatitis, erythroderma, pustular dermatitis, etc.), or vaccinees with household contacts having such skin disorders might also be at higher risk for eczema vaccinatum.

Infants ( < 12 Months Of Age) And Children

ACAM2000 has not been studied in infants or children. The risk of serious adverse events following vaccination with live vaccinia virus is higher in infants. Vaccinated persons who have close contact with infants, e.g., breastfeeding, must take precautions to avoid inadvertent transmission of ACAM2000 live vaccinia virus to infants.


ACAM2000 has not been studied in pregnant women. Live vaccinia virus vaccines can cause fetal vaccinia and fetal death. If ACAM2000 is administered during pregnancy, the vaccinee should be apprised of the potential hazard to the fetus . Vaccinees with close contacts who are pregnant may be at increased risk because live vaccinia virus can shed and be transmitted to close contacts.

Allergy To ACAM2000 Smallpox Vaccine Or Its Components

ACAM2000 contains neomycin and polymyxin B. Persons allergic to these components may be at higher risk for adverse events after vaccination. Both the vaccine and diluent vial stoppers do not contain latex material.

Management Of Smallpox Vaccine Complications

The CDC can assist physicians in the diagnosis and management of patients with suspected complications of vaccinia (smallpox) vaccination. Vaccinia Immune Globulin (VIG) is indicated for certain complications of vaccination live vaccinia virus smallpox vaccine. If VIG is needed or additional information is required, physicians should contact the CDC at (404) 639-3670, Monday through Friday 8 AM to 4:30 PM Eastern Standard Time; at other times call (404) 639-2888.

Prevention Of Transmission Of Live Vaccinia Virus

The most important measure to prevent inadvertent auto-inoculation and contact transmission from vaccinia vaccination is thorough hand washing after changing the bandage or after any other contact with the vaccination site.

Individuals susceptible to adverse effects of vaccinia virus, i.e., those with cardiac disease, eye disease, immunodeficiency states, including HIV infection, eczema, pregnant women and infants, should be identified and measures should be taken to avoid contact between those individuals and persons with active vaccination lesions.

Recently vaccinated healthcare workers should avoid contact with patients, particularly those with immunodeficiencies, until the scab has separated from the skin at the vaccination site. However, if continued contact with patients is unavoidable, vaccinated healthcare workers should ensure the vaccination site is well covered and follow good hand-washing technique. In this setting, a more occlusive dressing may be used. Semipermeable polyurethane dressings are effective barriers to shedding of vaccinia. However, exudate may accumulate beneath the dressing, and care must be taken to prevent viral spread when the dressing is changed. In addition, accumulation of fluid beneath the dressing may increase skin maceration at the vaccination site. Accumulation of exudate may be decreased by first covering the vaccination with dry gauze, then applying the dressing over the gauze. The dressing should be changed every 1-3 days .

Blood And Organ Donation

Blood and organ donation should be avoided for at least 30 days following vaccination with ACAM2000.

Limitations Of Vaccine Effectiveness

ACAM2000 smallpox vaccine may not protect all persons exposed to smallpox.

Patient Counseling Information

Please refer patient to the Medication Guide prepared for ACAM2000 Smallpox Vaccine.

Serious Complications Of Vaccination

Patients must be informed of the major serious adverse events associated with vaccination, including myocarditis and/or pericarditis, progressive vaccinia in immunocompromised persons, eczema vaccinatum in persons with skin disorders, auto- and accidental inoculation, generalized vaccinia, urticaria, erythema multiforme major (including Stevens-Johnson syndrome) and fetal vaccinia in pregnant women.

Protecting Contacts At Highest Risk For Adverse Events

Patients must be informed that they should avoid contact with individuals at high risk of serious adverse effects of vaccinia virus, for instance, those with past or present eczema, immunodeficiency states including HIV infection, pregnancy, or infants less than 12 months of age.

Self-inoculation And Spread To Close Contacts

Patients must be advised that virus is shed from the cutaneous lesion at the site of inoculation from approximately Day 3 until scabbing occurs, typically between Days 14-21 after primary vaccination. Vaccinia virus may be transmitted by direct physical contact. Accidental infection of skin at sites other than the site of intentional vaccination (self-inoculation) may occur by trauma or scratching. Contact spread may also result in accidental inoculation of household members or other close contacts. The result of accidental infection is a pock lesion(s) at an unwanted site(s) in the vaccinee or contact, and resembles the vaccination site. Self-inoculation occurs most often on the face, eyelid, nose, and mouth, but lesions at any site of traumatic inoculation can occur. Self-inoculation of the eye may result in ocular vaccinia, a potentially serious complication.

Care Of The Vaccination Site And Potentially Contaminated Materials

Patients must be given the following instructions:

  • The vaccination site must be completely covered with a semipermeable bandage. Keep site covered until the scab falls off on its own.
  • The vaccination site must be kept dry. Normal bathing may continue, but cover the vaccination site with waterproof bandage when bathing. The site should not be scrubbed. Cover the vaccination site with loose gauze bandage after bathing.
  • Don’t scratch the vaccination site. Don’t scratch or pick at the scab.
  • Do not touch the lesion or soiled bandage and subsequently touch other parts of the body particularly the eyes, anal and genital areas that are susceptible to accidental (auto-) inoculation.
  • After changing the bandage or touching the site, wash hands thoroughly with soap and water or > 60% alcohol-based hand-rub solutions.
  • To prevent transmission to contacts, physical contact of objects that have come into contact with the lesion (e.g. soiled bandages, clothing, fingers) must be avoided.
  • Wash separately clothing, towels, bedding or other items that may have come in direct contact with the vaccination site or drainage from the site, using hot water with detergent and/or bleach. Wash hands afterwards.
  • Soiled and contaminated bandages must be placed in plastic bags for disposal.
  • The vaccinee must wear a shirt with sleeves that covers the vaccination site as an extra precaution to prevent spread of the vaccinia virus. This is particularly important in situations of close physical contact.
  • The vaccinee must change the bandage every 1 to 3 days. This will keep skin at the vaccination site intact and minimize softening.
  • Don’t put salves or ointments on the vaccination site.
  • When the scab fall off, throw it away in a sealed plastic bag and wash hands afterwards.

Use In Specific Populations

Pregnancy Category D

ACAM2000 has not been studied in pregnant women. Live vaccinia virus vaccines can cause fetal harm when administered to a pregnant woman. Congenital infection, principally occurring during the first trimester, has been observed after vaccination with live vaccinia smallpox vaccines, although the risk may be low. Generalized vaccinia of the fetus, early delivery of a stillborn infant, or a high risk of perinatal death has been reported.

The only setting in which vaccination of pregnant women should be considered is when exposure to smallpox is considered likely. If this vaccine is used during pregnancy, or if the vaccinee lives in the same household with or has close contact with a pregnant women, the vaccinee should be apprised of the potential hazard to the fetus. Healthcare providers, state health departments, and other public health staff should report to the National Smallpox Vaccine in Pregnancy Registry all cases in which persons who received ACAM2000, or were exposed to a woman who received ACAM2000 within 28 days after vaccination, during pregnancy, or within 42 days prior to conception. Civilian women should contact their healthcare provider or state health department for help enrolling in the registry. Clinicians or public health staff should report civilian cases through their state health department or to CDC, telephone 404-639-8253 or 877 554 4625. Military cases should be reported to the DoD, telephone 619 553-9255, Defense Switched Network (DSN) 553-9255, fax 619 767-4806 or e-mail

Nursing Mothers

ACAM2000 has not been studied in lactating women. It is not known whether vaccine virus or antibodies are secreted in human milk. Live vaccinia virus can be inadvertently transmitted from a lactating mother to her infant. Infants are at high risk of developing serious complications from live vaccinia smallpox vaccination.

Pediatric Use

The safety and effectiveness of ACAM2000 have not been established in the age groups from birth to age 16. The use of ACAM2000 in all pediatric age groups is supported by evidence from the adequate and well-controlled studies of ACAM2000 in adults and with additional historical data with use of live vaccinia virus smallpox vaccine in pediatrics. Before the eradication of smallpox disease, live vaccinia virus smallpox vaccine was administered routinely in all pediatric age groups, including neonates and infants, and was effective in preventing smallpox disease. During that time, live vaccinia virus was occasionally associated with serious complications in children, the highest risk being in infants younger than 12 months of age. .

Geriatric Use

Clinical studies of ACAM2000 did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. There are no published data to support the use of this vaccine in geriatric (persons > 65 years) populations.

5 Poland GA, Grabenstein JD, Neff JM. The US smallpox vaccination program: a review of a large modern era smallpox vaccination implementation program. Vaccine. 2005;23:2078-2081.

About the author

Leave a Reply

Your email address will not be published. Required fields are marked *