Flu shot and antibiotics

Contents

Antibiotics May Make the Flu Vaccine Less Effective by Disrupting Gut Microbes

“Taking antibiotics clearly had a measurable reduction in the immune response, but we don’t know whether it’s clinically significant yet,” says Dr. Schaffner, who was not involved in the study. “It could be that if you’re taking antibiotics it might not be a good time to get a flu vaccine, but we’re not quite there yet in terms of research.”

He also points out that the antibiotic combination used in this investigation was not one seen in common practice.

“This antibiotic cocktail is a very unusual mix of ingredients,” says Schaffner. “It seems specifically designed to kill off as many gut bacteria as possible.”

For future research, Schaffner would like to see a larger study population and an antibiotic combination used in standard treatment.

“Significantly more work needs to be done to truly understand the real impact of the microbiome on influenza,” says Embry.

Embry adds that the NIH will continue to support research exploring factors that may improve human immune response to influenza vaccines.

Vaccination Is Recommended, Regardless of Antibiotic Use

“This study is early in nature,” says Embry. “Right now I’m not sure that there is anything to definitively say that you should wait to get the influenza vaccine if you’ve had antibiotic treatments. At this stage, I’d say that it is important to get the flu vaccine when it’s recommended to be administered for the upcoming season.”

The Centers for Disease Control and Prevention (CDC) still recommends that everyone age six months and older get an annual influenza vaccination. The flu vaccine reduces the risk of flu illness by between 40 and 60 percent among the overall population during seasons when most circulating flu viruses are well-matched to the flu vaccine, according to the CDC.

Share this
Article

  • Twitter
  • Email

You are free to share this article under the Attribution 4.0 International license.

University Stanford University

A new study in healthy adults suggests that antibiotics may reduce flu vaccine effectiveness.

The depletion of gut bacteria by antibiotics appears to leave the immune system less able to respond to new challenges, such as exposure to previously unencountered germs or vaccines, says Bali Pulendran, professor of pathology and of microbiology and immunology at the Stanford University School of Medicine.

“To our knowledge, this is the first demonstration of the effects of broad-spectrum antibiotics on the immune response in humans—in this case, our response to vaccination—directly induced through the disturbance of our gut bacteria,” he says.

From mice to humans

The idea that the trillions of bacteria inhabiting the human gut play a role in our health is far from new, but it hasn’t been rigorously proved. Hard data in humans has been sparse, with causal evidence coming mainly from studies in mice.

The new study was inspired by a mouse study that Pulendran and his colleagues conducted in 2011. Those investigators found that mice raised from birth to have germ-free intestinal tracts failed to mount as strong an immune response to vaccination as their normal counterparts. So did mice given antibiotics or bioengineered to lack an immune sensor for flagellin, the chief protein constituent of the threadlike flipper that bacteria use for swimming around.

When it comes to responding to vaccination against a previously encountered infectious pathogen, our immune systems are remarkably resilient even in the face of the most severe depletion of our intestinal bacteria.

“The question was, does this have any relevance to humans?” Pulendran says. To try to answer this question, he and his associates conducted a study involving 22 adults ages 18 to 45: During the 2014-15 flu season, 11 took broad-spectrum antibiotics over five days and got a flu vaccine on day four; 11 others took no antibiotics but got the flu vaccine on day four, as well.

The antibiotics lowered the gut-bacterial population by 10,000-fold. The resulting loss of overall diversity was detectable for up to one year after the antibiotics were taken. Still, 30 days after vaccination, vaccine-induced increases in antibodies capable of preventing influenza infection were comparable among the two groups.

But the participants in this experiment tended to have pretty high levels of those antibodies to begin with, suggesting they’d already had some exposure to the flu strains represented in the current or prior seasons’ vaccines.

Flu vaccine effectiveness

To see if low counts of gut bacteria might pose a greater obstacle to the immune system’s ability to respond to previously unseen elements in a vaccine—such as new viral strains represented in the seasonal flu vaccine—than to those the immune system remembered seeing before, Pulendran’s team recruited another 11 similarly aged participants for the 2015-16 season.

But this time, they selected only individuals whose low level of flu antibodies indicated low prior exposure to the virus or to the vaccine itself. None of the new recruits had gotten flu vaccinations for at least the past three years. Five individuals got broad-spectrum antibiotics, as in the previous year. The other six served as controls. All 11 got vaccinated.

Again, gut-bacteria counts in individuals who received antibiotics plummeted, as in the previous year. But this time there was a big change in levels of an antibody subtype most responsible for countering the influenza virus: This subtype failed to burgeon in the blood in response to the vaccine. Notably, the deficit in this antibody subtype correlated strongly with post-antibiotics decreases in total gut bacteria as well as in flagellin, the bacterial protein, in volunteers’ stool samples—a proxy for microbial abundance in the gut.

Lost resilience

The recipients of the antibiotics exhibited many signs of systemic inflammation—the same immunological signature Pulendran has observed among people ages 65 and older after an influenza vaccination in a prior study.

The degree to which antibiotics recipients’ immune systems exhibited this bodywide, aging-associated systemic inflammation mirrored the extent of depletion, in participants’ blood, of a series of metabolites whose generation requires gut-bacterial assistance. These metabolites, called secondary bile acids, are known to dial down inflammatory processes in the immune system. Intestinal bacteria fashion them from primary bile acids initially produced in the liver. Levels of one important secondary bile acid, lithocholic acid, plunged by 1,000-fold in the bloodstreams of antibiotic recipients, and was inversely correlated with the amount of inflammation.

“The study indicates that when it comes to responding to vaccination against a previously encountered infectious pathogen, our immune systems are remarkably resilient even in the face of the most severe depletion of our intestinal bacteria,” Pulendran says. “But they seem to lose this resilience when confronted with a vaccine containing new pathogenic elements of which they have little or no prior memory.”

You should still get the flu vaccine

The findings, Pulendran says, imply that when next season’s flu strain comes along, you want your gut-resident microbes to be in full bloom in order for your immune system to rise to the occasion. Pulendran offers some advice. “Get your annual flu shot,” he says. “The greater your inventory of immune memory to influenza strains bearing any resemblance to the one that’s coming over the hill, the more likely you’ll be able to deal with it, even if your gut microbes are in short supply.”

Other investigators at Emory University, as well as researchers at the Ragon Institute, the University of Chicago, Georgia State University, and the Food and Drug Administration contributed to the work. The study appears in Cell.

Funding came from the National Institutes of Health, the Soffer Endowment, and the Violetta Horton Endowment. Stanford’s departments of Pathology and of Microbiology and Immunology also supported the work.

Source: Stanford University

Antibiotics May Disrupt Gut Microbiome and Inhibit Immune Responses to Flu Shot

As influenza season draws near, public health officials are once again recommending vaccination with the seasonal flu shot for all individuals >6 months.
But now, a new study published in Cell, reports that oral antibiotics, which may alter or kill microorganisms in the gut microbiome, can affect immune responses to the seasonal influenza vaccine. The research was funded by the National Institute of Allergy and Infectious Diseases.
For the investigation, a team of researchers examined 33 adult participants. The first group, comprised of 22 participants was studied during the 2014-15 influenza season and the second group, made up of 11 participants, was studied during the 2015-16 influenza season.
According to the investigators, led by scientists at Stanford University, the participants in the first group had high pre-existing immunity to the virus strains contained in the seasonal flu shot of 2014-15; however, the group of 11 participants had low immunity to the virus strain in the 2015-16 vaccine.
Each of the enrolled participants received a seasonal flu shot. To evaluate the role of antibiotics, half of the participants in each group also received a 5-day oral course of a broad-spectrum antibiotic regimen containing neomycin, vancomycin, and metronidazole prior to vaccination.
The participants were required to submit stool and blood samples at various points up to 1 year after vaccination. The investigators analyzed the samples and tracked each participant’s immune response to the vaccine and observed the diversity and number of organisms present in their gut microbiomes.
Just as the study team hypothesized, most participants who received the 5-day course of broad-spectrum antibiotics had reduced levels of gut bacteria.
According to a press release, the study team observed that among the participants during the 2015-16, who had little prior immunity to the vaccine strains, the course of antibiotics hindered immune responses to 1 of the 3 virus strains in the vaccine, which were an H1N1 A/California-specific virus.
The investigators indicate that this finding signals that these participants would be less protected against infection with that strain when compared to those who had not received antibiotics. Furthermore, this finding supports earlier research results from mouse models.
Individuals who took antibiotics prior to receiving the flu shot also experienced changes to their immune system that led to a pro-inflammatory state, which is often seen in older adults who have received influenza vaccines. The investigators hypothesize that this condition is “related to the process by which the microbiome regulates the metabolism of bile acid—with fewer microorganisms, this process is disrupted.”
The study team notes that since human microbiomes change throughout life, further research could explore why older adults have different reactions to influenza vaccines and why they have weaker immune systems overall.

To stay informed on the latest in infectious disease news and developments, please sign up for our weekly newsletter.

5 things you need to know about antibiotics this flu season

When Joseph developed a persistent cough, he booked a visit with his longtime family physician. The doctor diagnosed bronchitis and recommended rest and plenty of fluids. “What about antibiotics?” Joseph asked. “The flu is going around my office, and I have deadlines to meet.” The doctor hesitated. Then he saw how anxious Joseph was and agreed to call in a prescription.

What’s wrong with this picture? Joseph and his doctor are unknowingly contributing to the rise of “superbugs,” or drug-resistant germs. Treating a cough with an occasional Tylenol or Advil won’t do any harm, even if the medication doesn’t relieve your symptoms. But antibiotics are different, as overuse and misuse can harm you ― and the people you love ― in the long term.

Read on to learn which flu treatments are most effective, how to avoid unnecessary antibiotics, and ways you can help fight the rise of dangerous superbugs.

Will antibiotics help the flu?

Antibiotics have no effect on the flu. The drugs won’t relieve your symptoms, reduce the length of your illness or boost your immunity to other germs. Sure, you may feel better after taking antibiotics, for a simple reason: You were already on the road to recovery. We all tend to seek treatment when our symptoms are at their peak. Over the next few days, as the virus runs its course, you start to feel better. But that would have happened even without medication.

Sometimes, antibiotics can actually make you feel worse. “Antibiotics are generally quite safe, but they do carry some risk,” says Daniel Knecht, MD, MBA, VP of clinical strategy and policy for Aetna. “They may cause diarrhea, allergic reactions and various other side effects.” It’s something to keep in mind if you’re tempted to take unnecessary antibiotics “just in case.”

How to treat flu symptoms

The best medicine for the flu depends on the timing. Besides the usual over-the-counter cold-and-flu formulas, doctors recommends the following:

  • The flu shot. You probably know that the flu vaccine helps you avoid developing the flu. But the vaccine also reduces the strength of the virus if you do catch it. (You might even mistake it for a mild cold.) The catch: You have to get your shot before you come down with the flu ― ideally at least a few weeks prior, so your body has time to build up defenses against the virus.
  • Drink lots of fluids. Staying extra hydrated can make you feel more comfortable and speed your recovery. Treat yourself to a favorite beverage that will encourage you to keep drinking: juice, electrolyte water, chicken soup or herbal tea with honey and lemon.
  • Home remedies. For stomach upset, some people swear by ginger root; natural ginger ale or ginger tea are two good sources. To relieve cough and nasal congestion, the fumes of a menthol ointment, like Vicks VapoRub, or eucalyptus oil (sniff from the bottle or add a few drops to hot water) can help you breathe easier. Inhaling steam is another way to soothe airways; use a humidifier or sit in the bathroom while you run a very hot shower. And you can break up mucus in your nose and throat by gargling with salt water or using a neti pot.
  • Tamiflu. Recommended only for high-risk individuals, like seniors and people with chronic medical conditions. Ask a doctor or pharmacist about prescription flu treatment. Tamiflu is an antiviral drug taken by mouth that prevents the virus from multiplying in your body. It decreases your symptoms and the length of time you’re sick. You must take Tamiflu at the first sign of symptoms. If you wait too long, the drug won’t work.

Antibiotic resistance refers to the ability of some germs to survive the drugs we take to kill them.

When you need antibiotics ― and when to avoid them

Viruses and bacteria are two types of germs that can cause infection and disease. Antibiotics kill bacteria, but have no effect on viruses. Some illnesses always require antibiotic treatment: strep throat, staph-based skin infections and common sexually transmitted diseases like chlamydia.

Other conditions may be caused by either bacteria or viruses, and it can be hard to tell the difference. If you develop pneumonia, pink-eye or a urinary tract infection, for instance, your doctor may test for bacteria before recommending antibiotics.

Will antibiotics help?

Always Sometimes Never
Strep throat UTI Cold
Tuberculosis Pink-eye Flu
Chlamydia Sinus infection Bronchitis
E. coli Pneumonia Yeast infection
Staph infection Ear-ache Herpes

Most illnesses that send people to their doctor are caused by viruses or allergies. That means antibiotics won’t help. Typically, you just have to let a virus run its course. Yet 30% to 50% of antibiotics are prescribed for viral illnesses, like bronchitis. “It’s very validating and comforting for patients to receive an antibiotic prescription when they’re not feeling well,” Dr. Knecht explains. “And doctors want to help.” But such overuse is a major contributor to antibiotic resistance.

What is antibiotic resistance?

Antibiotic resistance refers to the ability of some germs to survive the drugs we take to kill them. This can happen as a result of overuse, described above, or misuse, as when a patient with strep throat misses doses of their antibiotics or stops taking their pills once they feel better. Instead of being killed, the strep bacteria are, in the words of one scientist, “educated” in how to fight the drug. Then, if those germs are passed to someone else, the same antibiotic will be less effective.

“Superbugs” are germs that are resistant to many antibiotics. The best-known superbug is MRSA (pronounced MER-suh), a drug-resistant form of staph. Other superbugs cause hard-to-treat forms of pneumonia, tuberculosis, gonorrhea and UTIs. Every year, 2 million Americans fall ill with antibiotic-resistant infections.

Superbugs take more time and money to treat. Today, a simple sore throat or UTI might inconvenience you for a week, until your inexpensive generic antibiotics kick in. In the future, that week could turn into a month ― and multiple rounds of pricey specialized antibiotics.

That’s not all. “Antibiotics are the unsung hero that support many medical breakthroughs,” Dr. Knecht says. “There’s a whole slew of technologies we wouldn’t be able to use if antibiotics stopped working: surgery, dialysis, chemotherapy, gene therapy, bone marrow transplants.” All of these treatments would be too dangerous without effective ways to head off and treat infection.

How you can help fight superbugs

The good news is that we’re making progress in the battle against superbugs. Aetna is working to educate doctors about the dangers of overprescribing antibiotics for common complaints like acute bronchitis, in collaboration with the Centers for Disease Control and Prevention (CDC) and state Departments of Health. In 2018, the program reduced unnecessary prescriptions by 16%. In 2019, the initiative will be expanding to additional states.

But we need your help. You can fight the rise of antibiotic-resistant superbugs by asking the right questions and taking your medication as directed. If your doctor offers to prescribe you antibiotics, ask if they’re really necessary. “Doctors may think people are coming to them for antibiotics,” Dr. Knecht says. “Asking doctors if antibiotics are needed lets them know that you’re there for the right treatment, whatever that is.” And if you do need antibiotics for a bacterial illness, don’t skip doses and do take all the pills prescribed to you, even after you feel better. And don’t share antibiotics with others.

“Imagine a world where you don’t know if antibiotics will work,” Dr. Knecht urges. “Many people don’t recognize how important they are. We need to elevate their status and preserve this precious resource.”

About the author

Maureen Shelly is a health and science geek living in New York City.

Antibiotics found to reduce efficacy of flu vaccine by disrupting gut microbiome

A new study is offering the first evidence in humans to suggest depletion of gut microbiome diversity by antibiotics can reduce the efficacy of a vaccination. The research focused on a cohort administered with the influenza vaccine, hypothesizing gut bacteria to play a central role in immune response to vaccinations.

Last year a team of Australian researchers presented a mouse study finding antibiotics can severely impair an animal’s immune response to vaccinations. That research focused on young mice as proxies for human babies in their first year of life, and specifically examined five vaccines given routinely to infants, including meningitis and whooping cough.

An earlier Stanford study from 2011 found similar impaired immune responses in animal studies, particularly when mice were bred with no gut microbiome. Despite these studies associating microbiome with vaccine efficacy, until now no human studies had been conducted to examine the phenomenon.

“To our knowledge, this is the first demonstration of the effects of broad-spectrum antibiotics on the immune response in human – in this case, our response to vaccination – directly induced through the disturbance of our gut bacteria,” says Bali Pulendran, who worked on the 2011 Stanford research, and is senior author on the newly published study.

The new research first investigated a cohort of 22 adults during the 2014-15 flu season. Half the subjects received the flu vaccine as normal, while the other half were administered a trio of broad-spectrum antibiotics for five days immediately before getting the vaccine.

Unsurprisingly, the antibiotic group showed a 10,000 fold reduction in gut bacteria diversity, but more interestingly, both groups showed comparable levels of influenza-preventing antibodies 30 days after vaccination. The researchers discovered both cohorts displayed high-levels of targeted protective influenza antibodies before vaccination. This suggested the subjects may have previously been exposed to the specific strains of flu in the 2014-15 vaccine.

Those making up the second cohort investigated in the study the following year were specifically selected to make sure they indicated low-levels of antibodies to the specific strains in that year’s vaccine. The experiment was repeated, but this time the antibiotic group showed significantly lower antibody responses to one particular strain in the flu vaccine.

What this result suggested to the researchers is the subjects may have had no prior exposure to this particular flu strain. So while it seems antibiotics don’t influence your immune memory to previously confronted pathogens, it does affect one’s ability to generate immunity to a new pathogen.

“The study indicates that when it comes to responding to vaccination against a previously encountered infectious pathogen, our immune systems are remarkably resilient even in the face of the most severe depletion of our intestinal bacteria,” says Pulendran. “But they seem to lose this resilience when confronted with a vaccine containing new pathogenic elements of which they have little or no prior memory.”

In some ways this research is good news for those worried about whether antibiotics can directly reduce immune responses to illnesses from old vaccinations. The study does suggest immune memory can hold strong in the face of short-term microbiome disruptions. However, the study also implies fresh vaccine-induced immune responses can certainly be impaired in the face of acute microbiome disruptions from antibiotics. Pulendran doesn’t explicitly suggest we avoid taking antibiotics in close proximity to vaccinations. More research certainly needs to be done to better understand the mechanisms that may be at play, but he does remind people to get a flu shot regardless of antibiotic status.

“Get your annual flu shot,” say Pulendran. “The greater your inventory of immune memory to influenza strains bearing any resemblance to the one that’s coming over the hill, the more likely you’ll be able to deal with it, even if your gut microbes are in short supply.”

The new study was published in the journal Cell.

Source: Stanford Medicine

What are flu vaccines made of and why?

Share on PinterestMany vaccines contain similar ingredients, including a small amount of the virus or bacteria being vaccinated against.

Many vaccines for flu and other viruses contain similar ingredients. The purpose of each ingredient is to either make the vaccine effective or ensure that it is safe.

Many studies over the years have shown that flu vaccines are safe. The CDC say that it is the best way to avoid getting the flu and spreading it to other people.

The following list looks at seven ingredients in vaccines, including flu shots, and why vaccines need them:

1. Influenza viruses

The flu vaccine contains tiny amounts of the viruses it protects against. The presence of these viruses in the vaccine triggers the body’s natural defense mechanism to produce antibodies to fight them. This means that the body quickly recognizes them when exposed to the disease in “real life.”

Different influenza viruses contained in a flu shot are:

  • influenza A virus H1N1 called the Michigan strain
  • Influenza A virus H3N2 called the Hong Kong strain
  • one or two influenza B viruses called the Brisbane and Phuket strains

Traditional flu shots are trivalent (three-component) vaccines because they protect against three viruses: two influenza A viruses (H1N1 and H3N2), and one influenza B virus.

A person can also get a quadrivalent (four-component) vaccine, which protects against an additional B virus.

2. Formaldehyde

Formaldehyde is toxic and potentially lethal in high doses. However, it is present in such small amounts in a flu vaccination that it is harmless.

Formaldehyde’s role in the flu shot is to inactivate toxins from viruses and bacteria that may contaminate the vaccine during production, as well as the viruses naturally present in the vaccine.

Formaldehyde is typically present in the human body and is a product of healthy digestive function.

3. Aluminum Salts

Aluminum has been used in vaccines for over 70 years.

Aluminum salts are adjuvants, meaning that they help the body to develop a stronger immune response against the virus in the vaccine. Because they boost the body’s response, this means that the vaccine can contain smaller amounts of the virus.

Similar to formaldehyde, and to most ingredients in the flu shot, the amount of aluminum present in the vaccine is extremely small.

This compound is not always present in flu vaccines, some of which are aluminum-free.

4. Thimerosal

Share on PinterestThimerosal is not found in all flu vaccines.

Thimerosal is a preservative that keeps the vaccine free from contamination by bacteria and fungi. Without this, the growth of bacteria and fungi is common when a syringe is in a multi-dose vial (a vial that contains more than one dose).

Thimerosal is made of an organic form of mercury known as ethylmercury, a safe compound that usually only stays in the blood for a few days.

It is different from the standard mercury that can cause illness in large doses, and from the mercury found in seafood (called methylmercury), which can stay in the body for years.

Flu shots will only contain thimerosal when they are in a multi-dose vial. Single-dose vials, pre-filled syringes, and nasal sprays do not need to include this preservative because contamination is not an issue.

5. Chicken egg proteins

Proteins from chicken eggs help viruses to grow before they go into the vaccine.

Influenza viruses used in vaccines are usually grown inside fertilized chicken eggs, where the virus makes copies of itself. After that, the viruses are separated from the egg and placed in the vaccine; this means that the finished vaccine may contain small amounts of egg proteins.

The CDC say that the flu shot is typically safe for people with egg allergies, but those who have an egg allergy must mention it to the doctor before receiving the shot. A person with a severe egg allergy may require monitoring by a doctor following the injection.

Egg-free flu shots are also available.

6. Gelatin

Gelatin is present in the flu shot as a stabilizer. Stabilizers keep the vaccine effective from the point of production to the moment of use.

Stabilizers also help to protect the vaccine from the damaging effects of heat or freeze-drying.

Most flu vaccines use pork-based gelatin as a stabilizer.

7. Antibiotics

Antibiotics are present in the flu vaccine to keep bacteria from growing during the production and storage of the vaccine.

Vaccines do not contain antibiotics that may cause severe reactions, such as penicillin. Instead, vaccines contain other forms of antibiotics, such as gentamicin or neomycin. Neomycin is also an ingredient in many topical medications, such as lotions, ointments, and eye drops.

Disrupting the gut microbiome may affect some immune responses to flu vaccination

Media Advisory

Friday, September 6, 2019

This colorized transmission electron micrograph depicts H1N1 influenza virus particles.NIAID

WHAT:

The normal human gut microbiome is a flourishing community of microorganisms, some of which can affect the human immune system. In a new paper published this week in Cell, researchers found that oral antibiotics, which can kill gut microorganisms, can alter the human immune response to seasonal influenza vaccination. The work was led by scientists at Stanford University and funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The research team examined 33 healthy adult participants in their study. One group of 22 volunteers was studied during the 2014-2015 flu season, and the second group with 11 volunteers was studied during the 2015-2016 flu season. The group of 22 volunteers had high pre-existing immunity to the influenza virus strains contained in the 2014-2015 seasonal influenza vaccine. The group of 11 volunteers had low immunity to the 2015-2016 seasonal influenza vaccine’s virus strains.

All study participants received a seasonal influenza vaccine. Half the participants in each group also received a five-day course of a broad-spectrum antibiotic regimen (consisting of neomycin, vancomycin, and metronidazole) by mouth before receiving the vaccine. By analyzing stool and blood serum samples taken at various times up to one year after vaccination, the researchers tracked the participants’ immune response to the influenza vaccines, as well as the diversity and abundance of the organisms in their gut microbiomes.

As expected, most participants who received antibiotics experienced reduced levels of gut bacteria. In addition, among the 2015-2016 participants who had little prior immunity to the seasonal influenza virus vaccine strains, a course of antibiotics hindered their immune responses to one of the three influenza virus strains in the vaccine, an H1N1 A/California-specific virus. This likely indicates that should they be exposed to this H1N1 virus after vaccination, these participants would be less protected against infection with that strain than people who had not received antibiotics, according to the authors. This finding supports earlier research results in mice.

The researchers also found that people who took antibiotics experienced changes to their immune systems that promoted a pro-inflammatory state, similar to a condition seen in older adults who have received influenza vaccines. The investigators believe this pro-inflammatory state is related to the process by which the microbiome regulates the metabolism of bile acid—with fewer microorganisms, this process is disrupted. Humans’ microbiomes change naturally as they age, and the researchers suggest that further research on these pathways could provide insights into why older adults respond differently to influenza vaccination and why they have weaker immune systems overall.

ARTICLE:

WHO:

Alan Embry, Ph.D., Chief of the Respiratory Diseases Branch in NIAID’s Division of Microbiology and Infectious Diseases, is available to comment on this study.

CONTACT:

To schedule interviews, please contact Elizabeth Deatrick, (301) 402-1663, [email protected]

This press release describes a basic research finding. Basic research increases our understanding of human behavior and biology, which is foundational to advancing new and better ways to prevent, diagnose, and treat disease. Science is an unpredictable and incremental process — each research advance builds on past discoveries, often in unexpected ways. Most clinical advances would not be possible without the knowledge of fundamental basic research.

NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.

About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

NIH…Turning Discovery Into Health®

Flu vaccine FAQs

When am I most at risk from flu?

Flu circulates every winter and generally peaks in December and January. This means many people get ill around the same time.

But it’s impossible to predict how many cases of flu there will be each year or exactly when it’ll peak.

Does everyone need a flu vaccine?

No, just people who are at particular risk of problems if they catch flu.

Ask a GP about having an NHS flu vaccination if:

  • you’re aged 65 or over
  • you’re pregnant
  • you have a serious medical condition
  • you live in a residential or nursing home
  • you’re the main carer for an elderly or disabled person whose welfare may be at risk if you fall ill
  • your child is in an at-risk group and is aged 6 months or over

Some pharmacies also offer free NHS flu vaccination to adults and social care workers in the categories listed above. They do not offer this service for children.

You should also have the flu vaccination if you’re a healthcare or social care worker directly involved in patient care.

You may also be able to have the flu vaccine at your GP surgery or a local pharmacy offering the service if you’re a frontline health or social care worker employed by a:

  • registered residential care or nursing home
  • registered homecare organisation
  • hospice

Find out more about who should have the flu vaccine

Why are certain groups targeted for the flu vaccine?

Complications such as bronchitis and pneumonia are more common in people with other conditions, especially if they’re also older.

In long-stay residential homes, vaccination helps prevent the rapid spread of flu among residents.

Is my child entitled to the flu vaccine?

Children eligible for the free nasal spray flu vaccine include:

  • children aged 2 and 3 on 31 August 2019
  • children in primary school
  • children with a health condition that puts them at greater risk from flu

How long will the flu vaccine protect me for?

The flu vaccine will provide protection for you for the upcoming flu season. People eligible for flu vaccination should have the vaccine each year.

What type of flu vaccine will I be offered?

There are several types of flu vaccine.

You’ll be offered 1 that’s most effective for you, depending on your age:

  • children aged 2 to 17 in an eligible group are offered a live attenuated quadrivalent vaccine (LAIV), given as a nasal spray
  • adults aged 18 to 64 who are either pregnant, at increased risk from flu because of a long-term health condition, or a frontline health or social care worker are offered a quadrivalent injected vaccine – the vaccine offered will have been grown either in eggs or cells (QIVe or QIVc), both of which are considered to be equally effective
  • adults aged 65 and over will be offered either an adjuvanted trivalent injected vaccine grown in eggs (aTIV) or a cell-grown quadrivalent injected vaccine (QIVc) – both vaccines are considered to be equally effective

If your child is aged between 6 months and 2 years old and is in a high-risk group for flu, they’ll be offered an injected flu vaccine as the nasal spray is not licensed for children under 2.

Can I have the flu vaccine while I’m taking antibiotics?

Yes, it’s fine to have the flu vaccine while you’re taking a course of antibiotics, provided you’re not ill with a high temperature.

How long does the flu vaccine take to become effective?

It takes between 10 and 14 days for your immune system to respond fully after you have had the flu vaccine.

If I had the flu vaccine last year, do I need it again now?

Yes. The viruses that cause flu can change every year, which means the flu (and the vaccine) this winter may be different from last winter.

Can the flu vaccine cause flu?

No. The vaccine does not contain any live viruses, so it cannot cause flu.

You may get a slight temperature and aching muscles for a couple of days afterwards, and your arm may feel a bit sore where you had the injection.

Other reactions are rare, and flu vaccines have a good safety record.

For children, the nasal spray vaccine cannot cause flu because the viruses in it have been weakened to prevent this happening.

When is the best time to get my flu vaccine?

The best time to have a flu vaccine is in the autumn, from the beginning of October to the end of November.

If you have missed this time, you can have the flu vaccine later in the winter, although it’s best to get it earlier.

Is there anyone who cannot have a flu vaccine?

Yes. You should not have the flu vaccine if you have ever had an allergic reaction to a flu vaccine or 1 of its ingredients. This happens very rarely.

You also need to take precautions if you have an egg allergy.

Find out who should not have the flu vaccine

Can I get the flu vaccine privately?

Adults who are not eligible for a flu vaccine on the NHS can pay for a flu vaccination privately.

The flu vaccine may be available from pharmacies or in supermarkets.

It’s provided on a private patient basis and you have to pay. The vaccine costs up to £20.

Why is it recommended that healthcare workers are vaccinated?

Vaccination prevents healthcare workers passing flu on to, or getting flu from, their patients.

It also helps the NHS to keep running effectively during a flu outbreak, when GPs and hospital services are particularly busy.

Can I have a flu vaccine if I’m breastfeeding?

Yes. The vaccine poses no risk to a breastfeeding mother or her baby, or to pregnant women.

Is it OK to have the flu vaccine during pregnancy?

Yes. In fact it’s important to get the flu vaccine if you’re pregnant.

It’s safe to have at any stage of pregnancy, including in the first trimester and right up to the expected due date.

It helps protect the mother-to-be and her newborn baby from catching flu.

Find out more about the flu vaccine in pregnancy

AUSTIN (KXAN) – New research suggests taking antibiotics during flu season could make your flu shot less effective, according to the National Institutes of Health.

The research was conducted by giving healthy adults the flu shot and then giving half of the participants broad spectrum antibiotics. Most of the adults who took the antibiotics showed a decreased resistance to the flu.

Antibiotics vs. Vaccines

Antibiotics and vaccines are very different.

Vaccines prevent infections by exposing your body to dead virus cells that are grown inside of eggs. Your immune system learns how to fight these cells, so if a living virus does invade, your body already knows what to do. The more vaccines you get over the years, the more viruses your body will remember how to fight. This is called an immune memory. It’s why someone who caught chicken pox as a child is less likely to get it as an adult.

Antibiotics kill bacterial infections but have no impact on viruses.

But a virus can lead to a bacterial infection which then must be treated with antibiotics. Broad spectrum antibiotics, like those used in the research, kill several types of bacteria at once, some of which are healthy bacteria living in your digestive track.

Researchers found that the antibiotic recipients entered into a “pro-inflammatory state,” similar to what happens when people 65 and up get a flu shot. Without the healthy bacteria in their guts, the bodies of the recipients couldn’t reduce the inflammation.

Doctors say improving your body’s immune memory will help fight an infection if your gut microbes are in short supply. The best way to do this is by getting your annual flu shot.

Antibiotics May Affect Some Immune Responses to Flu Vaccine

The normal human gut microbiome is a flourishing community of microorganisms, some of which can affect the immune system. In a study reported in Cell, researchers from Stanford University found that oral antibiotics can alter the human immune response to seasonal influenza vaccination.

The research team examined two groups of healthy volunteers. One group of 22 people had high pre-existing immunity to the influenza virus strains in the 2014–2015 seasonal influenza vaccine. The second group, of 11 volunteers, had low immunity to the 2015–2016 seasonal influenza vaccine’s virus strains.

First, half the participants in each group received a five-day course of a broad-spectrum antibiotic regimen that included neomycin, vancomycin, and metronidazole. Then all study participants received a seasonal influenza vaccine. By analyzing stool and blood serum samples taken at various times for a one year after vaccination, the researchers tracked the participants’ immune response to the vaccines as well as the diversity and abundance of the organisms in their gut microbiomes.

It wasn’t a surprise that most participants who received antibiotics had reduced levels of gut bacteria. In addition, among the 2015–2016 participants who had little prior immunity to the seasonal influenza virus vaccine strains, a course of antibiotics hindered their immune responses to one of the three influenza virus strains in the vaccine, an H1N1 A/California-specific virus. This indicates that were they to be exposed to this H1N1 virus after vaccination, these participants would be less protected against infection with that strain than people who had not received antibiotics, according to the authors.

The researchers also found that people who took antibiotics experienced changes to their immune systems that promoted a pro-inflammatory state, similar to a condition seen in older adults who have received influenza vaccines. The investigators believe this pro-inflammatory state is related to the process by which the microbiome regulates the metabolism of bile acid; this process is disrupted if antibiotics diminish the size or diversity of the microbiome. The human microbiomes changes naturally as people age, and the researchers suggest that further research on these pathways could provide insights into why older adults respond differently to influenza vaccination and why they have weaker immune systems overall.

Source: Cell, Sept. 5

Vaccines & Antibiotics: A Safe Combo?

  • Larger text sizeLarge text sizeRegular text size

I’ve heard that children who are taking antibiotics for an illness — like an ear infection — should not get a vaccine at the same time. Is this true?
– Ishani

Not usually. For most kids, taking antibiotics for a mild illness (like an ear infection) shouldn’t keep them from getting their vaccinations on schedule. Antibiotics do not interfere with the ingredients in vaccines or cause a bad reaction in a child who has just been vaccinated.

Kids taking antibiotics for a moderate or severe illness should not get vaccinated until they recover from the illness — but this applies to all children who are sick, not just those who are taking antibiotics. That’s because it can be hard to figure out whether symptoms like a fever following a vaccination are a side effect of the vaccine or due to the illness itself. As soon as a child is feeling better, even if he or she is on antibiotics, the vaccine can and should be given.

If you’re concerned about your child’s health and the safety of getting vaccinated, talk to your doctor or the person administering the vaccine.

Reviewed by: Elana Pearl Ben-Joseph, MD Date reviewed: March 2019

Vaccine Ingredients – Antibiotics

Antibiotics are used to prevent bacterial contamination during manufacture. Most are removed during the vaccine purification process, but trace quantities remain in some vaccines. Because antibiotics can cause severe allergic reactions in children (like hives, swelling at the back of the throat, and low blood pressure), some parents are concerned that antibiotics contained in vaccines might be harmful. However, the antibiotics most likely to cause severe allergic reactions (e.g., penicillin, cephalosporins and sulfa drugs) are not contained in vaccines.

Antibiotics used during vaccine manufacture include neomycin, polymyxin B, streptomycin and gentamicin. Only minute quantities remain in vaccines (see table below). These small quantities of antibiotics have never been clearly found to cause severe allergic reactions. Therefore, the possibility that the trace quantities of antibiotics contained in vaccines cause severe allergic reactions remains, at best, theoretical.

Antibiotic content in vaccines licensed for use in the United States

mg = milligrams; ppm = parts per million; ppb = parts per billion

Measles, mumps, rubella (MMR®)

Quantity Neomycin (per dose): 0.025 mg

Measles, mumps, rubella, varicella (ProQuad®)

Quantity Neomycin (per dose): .005 mg to < 0.016 mg (depending on storage requirements)

Meningococcal B Vaccine (Bexsero®)

Quantity Kanamycin (per dose): < 0.00001 mg

Varicella (Varivax®)

Quantity Neomycin (per dose): Trace quantities

Rabies (Imovax®, RabAvert®)

Imovax

  • Quantity Neomycin (per dose): ≤ 0.15 mg

RabAvert

Influenza

Some influenza vaccines contain no antibiotics and others contain one or more of the following:

Polio (IPOL®)

  • Quantity Neomycin (per dose): 0.000005 mg
  • Quantity Streptomycin (per dose): 0.0002 mg
  • Quantity Polymyxin B (per dose): 0.000025 mg

Diphtheria, tetanus, pertussis, polio (Kinrix®, Pentacel®, Quadracel®)

Kinrix

  • Quantity Neomycin (per dose): ≤ 0.00000005 mg
  • Quantity Polymyxin B (per dose): < 0.00000001 mg

Pentacel and Quadracel

  • Quantity Neomycin (per dose): < 0.000000004 mg
  • Quantity Polymyxin B (per dose): < 0.000000004 mg

Diphtheria, tetanus, pertussis, hepatitis B, polio (Pediarix®)

  • Quantity Neomycin (per dose): 0.00000005 mg
  • Quantity Polymyxin B (per dose): < 0.00000001 mg

Hepatitis A (Havrix®, Vaqta®)

Havrix

Quantity Neomycin (per dose): < 0.00004 mg

Vaqta

Quantity Neomycin (per dose): < 10 ppb

Hepatitis A, hepatitis B (Twinrix®)

Quantity Neomycin (per dose): < 0.00002 mg

Goh CL. Anaphylaxis from topical neomycin and bacitracin. Aust J Dermatol. 1986 Dec;27(3):125-6.

Kwittken PL, Rosen S, Sweinberg SK. MMR vaccine and neomycin allergy. Am J Dis Child. 1993 Feb;147(2):128-9.

Leyden JJ, Kligman AM. Contact dermatitis to neomycin sulfate. JAMA 1979 Sep 21;242(12):1276-8.

MacDonald RH, Beck M. Neomycin: a review with particular reference to dermatological usage. Clin Exp Dermatol. 1983;8:249-258.

Yunginger JW. Anaphylaxis. Curr Prob Pediatr. 1992;22:130-146.

About the author

Leave a Reply

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