How you get sick?

Q. Can I catch the same cold twice?

A. Yes, you can catch the same cold twice, depending on the strength of your immune response.

Most of what we know about immunity to cold viruses is based on studies performed in the late 1950s and early ’60s. These were experiments in which volunteers — the term “volunteer” may be a bit generous here as the subjects were typically medical students or military recruits whose participation may have been less than fully voluntary — were intentionally infected with cold viruses.

In one landmark study from the late ’50s, over 1,000 stalwarts were inoculated with the infectious nasal secretions from a patient with an active cold. After becoming infected and being allowed to recover, the subjects were challenged again with the same virus to study their response. In a later, particularly rigorous study from 1963, 50 subjects were confined to a dormitory for an entire month to assess their ability to withstand reinfection with the same cold virus.

The results of these studies showed that for many people, infection with a cold virus can indeed provide effective immunity against subsequent exposure to that particular virus. More than half of the study participants made sufficient amounts of antibodies and were protected. Those who had a less robust antibody response, however, were not protected and came down with a cold after being reinfected.

But the good news is that it’s pretty rare to catch the flu twice in a single season. Having this happen would be “quite a stroke of bad luck,” Schaffner told Live Science.

Most people who get the flu this season are getting sick with the H3N2 strain. But a smaller portion of people (around 10 to 15 percent) are getting the H1N1 strain or the influenza B virus, according to data from the Centers for Disease Control and Prevention. (H3N2 and H1N1 are both strains of influenza A.)

Seasonal flu shots contain three to four strains of flu virus, because there isn’t much “cross protection” between strains, Schaffner said. It’s possible that getting sick with one type of influenza A virus would offer some modest protection against another type of influenza A, but it probably wouldn’t give you any protection against the influenza B virus, Schaffner said.

If you do catch the flu, and you haven’t received the flu vaccine for the season, doctors generally recommend that you still get a flu shot after you’re no longer sick, particularly if it’s early on in the flu season, Schaffner said. The CDC recommends the flu vaccine for everyone ages 6 months and older.

This flu season is turning out to be one of the worse since the 2009 “swine flu” epidemic, CDC officials said last week. Health officials are seeing “widespread’ flu activity across the entire country.

For the past five flu seasons, health officials found that flu activity was elevated for around 16 weeks. So far this season, flu activity has been elevated for nine weeks, meaning that the flu season may be only about halfway over, the CDC said.

Original article on Live Science.

While you’re at it, consider opting for a fist bump or high five instead of shaking hands. One study found that a handshake transferred nearly twice as many bacteria as the other two.

3. Get it on.
People who have sex on a regular basis may have higher levels of an immune system protein called immunoglobulin A (IgA). Researchers at Wilkes University in Pennsylvania found that college students who got between the sheets once or twice a week had higher levels of IgA compared to students who did it less often.
4. Mix up your meal plans.
Fad diets won’t do your immune system any favors. Instead, eat a wide variety of healthy foods. “There’s not just one specific nutrient or food component that’s linked to staying healthy,” says Jackie Newgent, RDN, author of The All-Natural Diabetes Cookbook. “Instead, it’s about synergy.”

A few tips:

  • Build your meal around vegetables. “Aim to fill half your plate with non-starchy vegetables, such as gingery stir-fried asparagus, roasted curry cauliflower, sautéed garlic spinach, fresh tomato salad, or grilled mushrooms — and always do this first,” Newgent says. Fruits and vegetables are full of nutrients called antioxidants that build up your immune system.
  • Drink green tea. It may increase the number of an important type of immune cell, called regulatory T cells, according to one study.
  • Try probiotics. A recent study in the British Journal of Nutrition showed that stressed-out college students who got these “good” bacteria had fewer sick days than those who didn’t. Even if they did catch a bug, they recovered faster. You can get probiotics from foods like yogurt — look for “live and active cultures” on the label — or take them as pills.

5. Get enough shut-eye.

Americans who said they had very good or excellent health and quality of life slept more — an average of 18 to 23 minutes per night — than those who rated their health as good, fair, or poor, according to the National Sleep Foundation.

No surprise. Your immune system needs sleep to keep you healthy. How much? Researchers found that people who log less than 6 hours a night are about four times more likely to catch a cold when they get the virus compared to those who get 7 hours of sleep a night.

Why do we get sick?

There are numerous ailments that can afflict the human body, ranging from carsickness to colds to cancer. The earliest physicians thought that illness and disease were a sign of God’s anger or the work of evil spirits. Hippocrates and Galen advanced the concept of humorism, a theory which held that we get sick from imbalances of the four basic substances within the human body, which they identified as blood, phlegm, black bile and yellow bile. Paracelsus, a Renaissance-era physician, was one of the first to posit that sickness comes from outside sources, rather than from within.

Today, we know that there are two major kinds of diseases: infectious and non-infectious. Infectious diseases are caused by pathogens such as bacteria, viruses, fungi and parasites. These pathogens can enter the body through the air we breathe, the food and drink we consume or through openings in the skin, such as cuts. As an example, think of a person who has a cold. That person may cough into his or her hand and then touch a doorknob, thus placing the cold virus on that doorknob. The virus may die on the doorknob, but it’s also possible that the next person to touch the doorknob will pick it up. If that person then touches food with the unwashed hand and consumes the food, the virus is now inside the body.


Not every pathogen that enters the body results in illness — our bodies come equipped with immune systems to fight off foreign agents. However, pathogens have the ability to adapt and evolve much more quickly than the immune system can, which means that pathogens sometimes have the upper hand when it comes to fooling the body’s defenses. One way that pathogens evade the immune system is by hiding within the body’s healthy cells. Additionally, some people have weakened immune systems that make it harder for them to resist the effects of an invading pathogen.

Non-infectious diseases aren’t caused by pathogens and can’t be spread person-to-person. These diseases are more likely to be caused by a confluence of factors including the environment, a person’s lifestyle choices and genetics. For example, skin cancer is usually the result of people spending too much time in the sun without protection from the sun’s UV rays, which is considered an environmental factor. A condition like heart disease may be caused by a sedentary lifestyle and a poor diet, or it may be caused by a family history of the disease. Though we may not be able to change our genetic code, there are plenty of things that humans can do to prevent noninfectious diseases. Most notably, we can choose to eat healthfully and exercise. We can also reduce our exposure to avoidable risk factors such as cigarette smoke.

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Most people understand that public places and common spaces are rife with germs, and special care must be taken during cold and flu season to prevent the spread of germs. Reducing your chances of getting sick requires more than diligent handwashing — it requires you to commit to a healthy lifestyle. While you can’t avoid germs altogether, you can help protect yourself and your family from illness by being mindful of the most common ways people get sick and taking steps to strengthen your immune system.

Here are five things that make you susceptible to illness:

1. Excessive worrying or stress

A little nervous tension here and there is normal, but persistent anxiety often results in a host of issues, including acid reflux, skin rashes, insomnia, depression, and a weakened immune system. Worry warts and cool cucumbers alike are susceptible to catching a cold, but those who prioritize stress management and self-care can expect to reap the rewards of a balanced immune system.

2. Frequently touched surfaces

Everything from subway poles to door handles to elevator buttons pose a threat because of the sheer volume of germs covering public surfaces, as well as how long viruses can survive on inanimate objects. The flu virus, for example, can last up to two days on a given surface, whereas strep pneumonia can contaminate an object for up to three weeks. Practice proper handwashing techniques in order to help avoid catching a bug, cold, or other virus.

3. Smoking

Smoking cigarettes degrades the tiny, disease-fighting hairs that line your nasal passages and lungs, putting you at greater risk of contracting a virus or infection. Smokers with damaged lungs are also more likely to suffer complications of the respiratory variety, which could lead to more serious, chronic conditions.

4. Drinking

Alcohol consumption is directly related to immunity and your body’s ability to fight infection. In fact, one study demonstrated on lab mice indicates that the aftereffects could reduce immune efficiency for up to 24 hours. If you decide to indulge in a cocktail or two, focus on staying hydrated by consuming plenty of water throughout the evening.

5. Lack of sleep

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If you struggle to get a good night’s rest, you could find yourself battling colds or other bugs more frequently than the well-rested portion of the population. Studies show that people who don’t get quality sleep or enough sleep are more likely to get sick after being exposed to germs like the cold or flu virus. As you sleep, your immune system restores itself and prepares to release infection-and inflammation-fighting proteins. So, getting the proper amount of shut-eye is crucial to your overall well-being.

Whether you’re the parent of young children or you work among the public, there are steps you can take to avoid getting sick. Wash your hands frequently and thoroughly, especially after doing things like shopping or traveling via public transit. Adhere to a diet rich in immune-boosting foods, such as antioxidant-rich blueberries, probiotic-packed Greek yogurt, and zinc-filled fish. And if you do catch a bug, consult your physician.

Are you one of those unlucky people who picks up every single nasty cold on the block, while your bulletproof friend seems to drink tequila for breakfast and remain mysteriously immune to all ailments?

If this sounds familiar, you may be wondering what your friend’s secret is. Why do some people get ill all the time while others cruise through life on a wave of magical immunity? And most importantly, how can you join the strong constitution club?

Why do some people never get sick?

Research suggests that, on average, each individual picks up around 200 colds in their lifetime. But some people seemingly never get ill and don’t take their fair share of the sickness pie. So what is their secret?

According to science, there isn’t one (yet). While some people may appear to suffer more than others with various ailments, it is a phenomenon that mainly has self-reporting to blame, as there is no hard evidence suggesting any other factors are at play.

While some suffer more than others with various ailments, it is a phenomenon that mainly has self-reporting to blame.

‘Some of us inherit a set of immune system genes that are particularly good at dealing with one particular virus,’ Daniel Davis, professor of immunology at the University of Manchester, told The Guardian. ‘But that is not to say that you or I would have a better or worse immune system. All it means is that you would deal with a particular flu virus better than me. There is an inherent diversity in how our immune systems respond to different diseases and that diversity is essential to how our species survives disease.’

Professor Davis went on to explain that the sheer diversity that exists within our immune systems makes sweeping generalisations about immunity little more than folklore. Indeed, he added, it even calls into question the benefits of all the products claiming to boost immunity levels, such as vitamin supplements or health teas, many of which are targeted at those among us whose health seemingly suffers more.

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Although science might not support the concept of superhuman health (at least not yet), it is well-known and extensively documented that certain lifestyle choices can help boost your immunity and give you a better chance of fighting off the cold that’s been making it’s way around the office.

Try these top tips to boost your immunity and fight off ailments:

Early exposure and your immune system

It might be a bit late for this if you’re an adult, but if you expose your children to certain levels of bacteria and viruses as they grow up, the more resilient their immune systems will become later in life. It means they might be less likely to succumb to certain allergies.

This is called the ‘hygiene hypothesis’, and is backed up by research suggesting that widespread use of disinfectant, antibacterial products and avoidance of dirt could stop children developing healthy gut bacteria.

Obviously we don’t suggest you encourage your children to eat rotten food or skip bath time completely, but do make sure they spend time playing outdoors, and don’t worry too much if they come back covered in mud!

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Exercise and your immune system

The recommended amount of exercise in order to achieve optimal health stands at 150 minutes of moderate aerobic activity a week (that’s 30 minutes a day for five days), alongside two sessions of strength exercises.

Evidence carried out by Harvard Medical School suggests that regular exercise boosts immunity and improves circulation – not to mention all the other wonderful things it can do for both your mental and physical wellbeing, so get moving!

The importance of sleep quality and health

Sleep has been proven to have a huge impact on the immune system. Indeed, one study published in The National Center for Biotechnology Information found that your chances of catching a cold are up to four and a half times greater in people who only manage five and a half hours of shut-eye per night, compared to those who achieve the recommended seven hours.

If you struggle to switch off at night and find it tricky to achieve your seven hour quota, try our mindfulness techniques to help you sleep.

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The link between stress and illness

Professor Davis cites stress as the ‘best established link’ in terms of how lifestyle impacts the immune system. Partially, this is because chronic or long-term stress produces cortisol. In the short term, cortisol helps to fight infection but when its levels are continuously high, it can have a negative effect, suppressing and weakening the immune response towards potential viruses or illnesses.

It’s been well documented that stress is bad for your mental and physical wellbeing, so working on stress-busting techniques will benefit your health in general, and hopefully in turn give you the strength the fight off that nasty cold!

Last updated: 01-10-19

Dr Juliet McGrattan (MBChB) Dr Juliet McGrattan Dr Juliet McGrattan spent 16 years as a GP, two years as a Clinical Champion for Physical Activity for Public Health England and is the Women’s Health Lead for the 261 Fearless global running network. Her award winning book, Sorted: The Active Woman’s Guide to Health was published by Bloomsbury in 2017.

It’s that time of the year when it seems like everyone you know has had a cold, flu or some other nasty bug.

After being sick, we’ll do anything to avoid getting reinfected. So, does that mean we need to toss out the toothbrush? What else do we need to ditch to stay healthy?

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Luckily, you can’t be reinfected by the same cold virus, but there are some 200 different strains circulating at any given time.

“You develop antibodies for each of the viruses you are exposed to,” said Dr. Natalie Azar, NBC medical contributor. “If you are having a cold that feels like it just doesn’t quit, it is probably a different cold virus.”

Charles Gerba, a professor of microbiology and environmental sciences at the University of Arizona, agreed.

“It is hard to re-infect yourself,” he said.

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After being exposed to a virus, the body creates antibodies to fight off the virus. When you recover from that particular virus, your body no longer remains susceptible to that strain.

As for re-exposure, that virus on the toothbrush, lip balm, mascara, sheets or towels won’t make you sick again. But if other viruses and bacteria linger on these items, a new illness can develop.

Flu, staph, strep, e-coli, and yeast commonly live on toothbrushes said Dr. Heather Rosen, medical director of UPMC North Huntington Urgent Care.

“There are so many bacteria that can reside on a toothbrush; therefore, it is always best to get rid of it once you have been infected with some sort of viral or bacterial illness,” she said.

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And, replacing your toothbrush after illness reduces the chance that your nasty brush spreads its germs to anyone else’s nearby brushes.

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Yuck factor

On the other side, Gerba says not to worry too much about toothbrushes spreading illness.

“It is just a yuck factor,” he said.

However, it is generally recommended to change your toothbrush every three months. And keep it away from the toilet, because airborne droplets released from flushing settle on toothbrushes, Gerba advised.

And, never share toothbrushes.

“You can catch infections like a cold, bloodborne disease , or even bacterial infections if you take a chance and use someone else’s toothbrush,” Rosen said.

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How about that lip balm?

When we’re sick and dehydrated, lip balm becomes our next best friend — after nasal tissue and a cup of hot green tea.

Fortunately, lipstick, lip balms and mascara often contain anti-microbial ingredients, reducing the number of germs flourishing in them, said Gerba.

But, don’t share makeup! People can still get sick if they borrow someone else’s make-up; it’s an easy way to contract oral herpes or pink eye, says Rosen.

Most lip balms contain anti-microbial agents. Angeliki Jackson / TODAY

It’s not about you

When it comes spreading colds and influenza, bar soap and towels can be germ factories. After rubbing hands on the soap, the germs remain on the bar, said Gerba. If people fail to sufficiently wash the germs off their hands, the leftovers may cling to hand towels.

“They can be a conduit for transmitting germs,” said Gerba. “Change those towels every two or three days.”

Sheets can also harbor germs, which could infect a healthy bed partner if they remain unwashed after illness.

If you’ve been sick, be kind to your loved one: wash your sheets.

“Viruses can survive much, much shorter periods of time on a porous surface,” says Azar. But they can linger up to 24 hours on hard surfaces, such as counters, tables, computer keyboards, and remote controls.

It doesn’t take much to clean away most germs, fortunately. Azar suggests thoroughly cleaning the house, sheets and towels after illness “if you want to be kind to other people. It’s not about you — it is about other people.”

Pretty Much All of Your Weird Germ-Avoidance Behaviors Are Pointless

In general, you shouldn’t worry about using Purell immediately after exposure to pathogens. As long as you don’t touch your eyes, mouth, or any other mucosal surface, you should have plenty of time to wash away the germs—anywhere from five minutes to five hours for bacteria.

On the other hand, excessive removal of bacteria, either with soap or hand sanitizer, may hinder your body’s natural ability to fight off infection. “Remember, your skin has its own bacteria, and they don’t really want to share the niche with the invading bacteria,” says Blaser. Scrub away too much of these bacterial defenses, and you’ll actually be more vulnerable to disease.

Mason says that instead of trying to kill all bacteria—which, even if it were possible, would not be desirable—we should focus on “enrich our skin, and also our buildings and our cities, for good bacteria.” That could mean everything from installing probiotic surfaces to designing ventilation systems with microbial filtration in mind. Research into the biology of the built environment is evolving and could have wide-reaching impacts on future building design.

What actually works

The bottom line is that you shouldn’t live in fear of high-traffic surfaces. According to Blaser, this type of contact simply isn’t the way people get sick. “We don’t get much disease from surfaces,” he says.

There is no evidence that subway handholds and toilet seats are significant transmitters of disease. There is no evidence that people who commute by public transportation are more likely to get sick than people who drive. And there is no evidence that health care workers are sicker than anyone else—even though they’re constantly exposed to life-threatening pathogens.

That’s because it takes more than the presence of bacteria or viruses to cause disease. “Many people think that the presence of an organism is tantamount to risk of disease, but it’s not,” says Blaser. “Presence has to be there, but the risk of disease can be infinitesimally remote—so remote, in fact, that it approaches zero.”

The risk is greater during cold and flu season, however; that’s when it pays to practice extra vigilance. Purell is especially effective when there are a lot of people coughing and sneezing and a high concentration of germs in the air. But in times when most people are healthy, Blaser says, it’s not clear that it offers much benefit.

There are some simple things you can do to help prevent illness: Wash your hands before you handle food and after you use the bathroom. Avoid people who are sick. Don’t smoke, which lowers your immunity. Don’t bite your nails or touch your face, the main entry point for germs. And, most importantly, maintain healthy habits: eat right, exercise, and get plenty of sleep. Those are the best ways to support your immune system. Using your palm to grip a subway pole doesn’t have anything to do with it.

Top image: PathDoc/.com

It’s the dreaded cold and flu season. Most adults get sick once or twice a season, but if you have small kids in the house, it’s even worse. Studies show your child could be coping with symptoms such as sniffles or fever six to 10 times before the season is over.

How can you keep everyone else in the home healthy when one person is sick? Here’s a simple prescription for health this cold and flu season.

Wash Your Hands the Right Way

Wash your hands every chance you get for as long as it takes to sing Happy Birthday twice. It’s the single most effective way to keep from getting sick from any type of germ. Use warm water. Plain soap is fine. It’s the act of rubbing your hands together that’s most effective.

Don’t Touch Your Nose or Face

Most viruses are passed by contact with mucus fluids, so keep your hands away from your mouth, nose, and face. This tip is important throughout cold and flu season, but it’s especially important directly after contact with a sick person.

Change Toothbrushes

Change toothbrushes often — every three months in general –and immediately after any sickness, or the sick person could become reinfected. Each family member should have their own color-coded toothbrush, stored at least an inch apart to avoid cross contamination.


If possible, isolate the sick person in your family. For instance, sleep in a different bedroom, or have other siblings avoid your sick child’s room. If you can’t do that, then sleep with your back to the sick person. Don’t let sick kids crawl into bed with mommy and daddy.

Sanitize Common Areas

Did you know the most common type of cold virus, the rhinovirus, can live on inanimate objects like telephones and stair railings for several hours, maybe even a few days? Using a disinfectant, sanitize areas that many people in your family touch: telephones, remote controls, computer keyboards, door knobs, refrigerator doors, sinks, etc.

Don’t Share

Obviously you don’t want to eat or drink after a sick person. Consider color coding drinking glasses or using disposable ones for the duration of the sickness. Color coding is also a good idea for hand and bath towels, so that family members don’t spread germs. And be sure to wash all towels, sheets, and linens more often during cold and flu season.

At the first sign of a cold or flu, you may wonder how it happened — especially if you’ve taken steps to avoid germs. Here’s exactly how you get sick, and what you need to know to protect yourself next time.

  • Viruses spread through tiny droplets in the air that are released when a sick person sneezes, coughs, or blows their nose.
  • You can get sick if you touch your nose, eyes, or mouth after you have touched something contaminated by the virus, such as a toy, countertop, or doorknob. Viruses can live on those objects for up to 2 days.
  • If you come in contact with cold or flu germs, your chance of getting sick isn’t 100%. It depends on when the other person was infected, and how many viral particles are contained in the droplets.
  • People are most contagious during the first 2 to 3 days of a cold. A cold is most often not contagious after the first week.
  • People who have the flu may pass it on to others 1 day before symptoms start and up to 5 to 7 days after getting sick, so they may spread the flu before they even know they are sick.

How to catch a cold

As the calendar pages fall away and autumn creeps toward winter, we slog through the inevitable cold and flu season. You know those first, scratchy-throated signs that a cold has taken hold. And you know you’re in for about a week’s worth of unshakeable symptoms – a dry, sore throat, stuffed-up nose, and coughing and sneezing fits. Want to make sure to get in on all that fun? Here are some surefire ways to catch a cold:

  • Become a sneeze guard. Cold viruses get spread around by mucus and saliva flung out of the body by sneezes and coughs. Thus, if you really want to catch a cold, try standing downwind of someone who already has one.
  • Touch everything and never wash your hands. While most cold germs are airborne, many get passed around on our hands. Thoroughly washing your hands or using hand sanitizers will remove many of the germs, but cold viruses can lurk anywhere hands have touched: door knobs, toilet flushers, telephones, bus or subway poles, other people’s cell phones, and shopping cart handles. The machines at the gym and the buttons on the ATM, too. So touch everything – especially your nose and mouth!
  • Stick your nose out. Temperatures drop and you bundle up in coats, scarves, and gloves, but your nose often gets left out in the cold. One catch-a-cold theory goes that when your nose is cold, you become less resistant to infection.
  • Walk barefoot in the cold. Your grandma may have warned you about “catching your death of cold” if you dared go out outside with a wet head in wintertime. Well, it seems your grandma may be at least partly right. You see, many of us carry cold viruses around with us all the time, but we just don’t always show the symptoms. Researchers at Cardiff University in Wales suggest that when the feet are cold, blood vessels in the nose constrict. This then makes it tough for your nose to fight off the virus and cold symptoms kick into high gear. So it seems like we just “caught” a cold, but it had been there waiting for a chill all the time.
  • Hang out in the city. Cities are packed full of virus carriers – building ventilation systems, people walking or riding on buses and in cars, children going to and from school, and people crossing paths in hospitals, malls, and any number of other public gathering places.
  • Stress out. Want a cold? Worry! Get anxious! It’s thought that tension can make you less resistant to infection.
  • Stop aging. With age comes wisdom, and this is true with your immune system, too. With every cold you battle, your immune system creates more and more antibodies and becomes smarter at handling new viruses that come along.
  • Be human. No wonder it’s called the common cold: Over two hundred different viruses float around and infect us humans every year, causing those familiar, unpleasant symptoms. Adults suffer an average of 2 to 5 colds each year, while kids experience 7 to 10 sniffle-and-sneeze episodes.

In all seriousness, it is tough to fend off all of the viruses that create cold symptoms. But you can lower your risk by turning all of those tips on their head – well, except for those last two!

  • Cover your mouth when you sneeze and cough. Keep germs off of your hands by coughing and sneezing into the bend of your elbow. And, of course, stay out of the line of fire of other people’s germs.
  • As much as you can, refrain from touching your nose, eyes, or mouth when in public. Wash your hands with soap and water often and for at least 15 to 30 seconds – it’s the best way to remove germs you’ve picked up from touching things around you. Hand sanitizers will tide you over until you can get to a sink.
  • Learn to cope with stress in your life.
  • Bundle up when you head out into the cold, and don’t forget your poor vulnerable nose!
  • Try to steer clear of crowded places during the high contagious season. Stay home from work or school if you’re sick to prevent spreading the cold you’ve “successfully” caught.

Amy Toffelmire

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