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When Not to Get Your Flu Shot

It could cause more harm than good if you're in these categories.

Every year, up to 49,000 Americans die from the flu or from complications with the illness—and every year, flu vaccination reduces the risk by between 40% and 60%, according to the American Lung Association.

That's why the flu shot is so important. However, there are certain times when a flu shot may be more dangerous to you than the illness itself.

While most doctors urge patients to get their flu shots each year—you'll want to get yours before the end of October; it takes two weeks to kick in—even they agree that there are certain situations when you should avoid or postpone your shot. Find out if you're safe to get stuck this year or if you should sit this one out. And to ensure your house is safe for you and the entire family, don't miss this essential list of 100 Ways Your Home Could be Making You Sick.


You're allergic to eggs

Woman refusing to eat eggs

Most flu shots are manufactured using egg-based technology. Therefore, the vaccine itself may contain a small amount of egg protein called ovalbumin. If you have a severe allergy to eggs or egg-based products, there's a small chance that the flu shot may cause an allergic reaction. If the allergic reaction you usually have to eggs is simply hives, the CDC recommends that you have your flu shot nonetheless and seek treatment if needed.

If your allergic reaction to eggs is usually more severe, such as anaphylaxis, the CDC concludes that you can still get your flu shot, but it should be administered, "in an inpatient or outpatient medical setting (including but not necessarily limited to hospitals, clinics, health departments, and physician offices), under the supervision of a health care provider who is able to recognize and manage severe allergic conditions." While anaphylaxis is a life-threatening condition, a recent CDC study found that only 1.31 per one million vaccine doses administered resulted in anaphylaxis.


You have something physical to do tomorrow

woman giving presentation to coworkers during meeting

Have a marathon you're running tomorrow morning? Scheduled to host a lengthy and involved presentation at work all day? You may want to wait to get your flu shot. While it's been proven that the flu shot won't give you the flu, according to the U.S. Department of Health & Human Services, there are some side effects you may feel for a few days after getting the vaccine. These side effects may include:

  • Redness, swelling, or pain at the flu shot injection site
  • Upset stomach
  • Fever
  • Muscle aches
  • Headache

In some cases, you may not feel any negative side effects after getting your flu shot. However, if you can plan your shot around a slow week, it may be best, just in case you feel a little under the weather after getting your vaccine.


You feel moderately or severely ill

woman is looking at the thermometer. She has fever

You can still get a flu shot if you have a simple cold or mild illness. However, if you're moderately or severely ill, it may be best to wait until you feel better to get the flu vaccine. Dr. Monique May, MD, warns the flu shot is also not recommended "if you actually have the flu at the time you go for the shot."

When you're severely sick, your body's immune system is busy trying to fight off your illness. If you get a flu shot, your body may be delayed in producing the immunity response to the flu that the vaccine is trying to achieve. Since your immune system is trying to do two things at once, it may also take you longer to recover from your illness if you get a flu shot when you're sick.

Moderate or severe illness may include a fever or other symptoms. Talk to the medical provider or your doctor if you're not feeling well but you're scheduled for your flu shot. You may need to reschedule when you feel better so your body can fully recover first.


You have a fever

Sick man having fever, drinking hot healing tea and touching forehead in bed,

You can still get a flu shot if you have a mild cold. However, if you currently have a moderate to severe illness, you should hold off on getting vaccinated until you feel better. A fever is a sign that your body is ill and your immune system has kicked into high gear. It's doing everything it can to fight off this illness. According to the Mayo Clinic, an adult has a fever if his or her temperature is elevated at all from the usual 98.6 degrees Fahrenheit.

Adding a flu vaccine to the mix may complicate what your body is going through. According to Dr. Aditya Gaur, MD from St. Jude Children's Research Hospital, "In someone who is moderately to severely ill, the healthcare provider may delay giving the flu shot to avoid confusing signs and symptoms of their illness with side effects of the vaccine."


You had a severe reaction to the shot last year

Woman suffering respiration problems sitting on a couch in the living room at home

If you experienced a severe reaction to your flu shot last year, talk to your doctor first before heading in for this year's vaccine. In most cases, the reaction you experienced wasn't related to the flu shot at all. However, in some cases, it may be a sign that you're allergic to a component used in the flu vaccine. According to the Mayo Clinic, "The flu vaccine isn't recommended for anyone who had a severe reaction to a previous flu vaccine."

According to Dr. May, you'll know you're having a severe allergic reaction if you experience "lip or tongue swelling, wheezing, hives, hoarseness, difficulty breathing, paleness or a fast heartbeat."

Your doctor may still recommend that you get the flu vaccine since this illness can be dangerous and lead to serious complications. Your medical provider may want to monitor you or have another medical professional observe your reaction to the vaccine this year, just to be safe.


If you're over 65 years of age, you may need a special vaccine


If you're older than 65 years of age, the CDC labels you as "high risk" for developing complications connected to the flu. As we age, our immune system becomes weaker, making it harder for your body to fight off the illness, so it can lead to chronic conditions or even death. The CDC estimated that between 70% and 90% of flu deaths in recent years occurred in people who were older than 65.

It's not that you should skip the flu shot if you're older than 65 years of age, but that you should get a special high-dose flu vaccine instead. The CDC recommends a flu shot that has four times the antigen as the regular vaccine. After conducting a clinical trial with over 30,000 participants, the CDC concluded, "adults 65 years and older who received the high-dose vaccine had 24% fewer influenza infections as compared to those who received the standard dose flu vaccine."


You're allergic to gelatin

young woman scratching her arm with allergy rash

If you have a gelatin allergy, it's important to consult with your medical provider before getting a flu shot. According to Dr. Stephanie Albin Leeds, MD, an allergist from Northwell Health, "Gelatin is used in the flu shot, as well as other vaccines, as a stabilizer. Because it is found in the vaccine, those with a known allergy to gelatin can experience allergic reactions, such as hives, sneezing, and difficulty breathing."

A gelatin allergy is rare, but if you know you are allergic, you can still get the flu shot. However, it should be administered by a board-certified allergist. He or she can observe you after administering the shot and take the necessary steps to reverse an allergic reaction, if one does occur.


You already got your shot for the year

woman being vaccinated

The CDC recommends that you get your flu shot by the end of October so you're prepared for the start of flu season. However, if you don't get your flu vaccination within this timeframe, it's not too late. Dr. Monique May, MD, advises, "Since it takes about 2 weeks for the flu shot to take effect, the latest I would recommend would be February to March."

Keep in mind, you only need to get one flu vaccine annually. If you have already obtained your flu shot, you won't need to get it again until next year. Once the vaccine is in your system, another shot won't increase your immunity to the illness.


You're allergic to certain antibiotics


If you or your child is allergic to antibiotics, talk to your doctor first before getting a flu shot. Some flu shots don't contain any antibiotics. However, according to the Children's Hospital of Philadelphia, certain flu shots may contain one or more of the following types of antibiotics:

  • Quantity Neomycin (per dose): < 0.00002 mg – 0.000062mg
  • Quantity Polymyxin B (per dose): < 0.011mg
  • Kanamycin (per dose): < 0.00003 mg
  • Gentamicin (per dose): < 0.00015 mg

These antibiotics are sometimes added to the flu vaccine to prevent bacteria from contaminating it during the manufacturing process. If you're worried about an allergic reaction to the vaccine, keep in mind the antibiotics used are not usually the same ones you may be allergic to. The most common antibiotic allergies are to penicillin, cephalosporins, or sulfa drugs, which are not used in flu vaccine production. Although you shouldn't have an allergic reaction to the shot, it's always best to check with your doctor before you get the vaccine.


Children six months or younger don't need it

If you have a child younger than six months, the Centers for Disease Control and Prevention recommends that you do not have him or her vaccinated for the flu just yet. At this age, children are too young for the flu shot and their bodies and immune systems can't handle the dosage provided in the vaccine.

Dr. Claire McCarthy, MD, from Boston Children's Hospital, agrees that the flu vaccine is the best way to prevent the flu, but warns that "children less than six months old can't get the flu shot." While you want to prevent your young child from dealing with this miserable illness, you'll need to wait until he or she is old enough to handle the flu shot. In the meantime, have your family members get their flu shots and keep their hands clean to prevent your child from gaining exposure to the germs that cause the flu.


Children between six months and eight years old need something else

Doctor injecting vaccination in arm of asian little child girl

If your child is between six months and eight years old, he or she doesn't need one regular flu vaccine but may need two doses of the flu shot. Children in this age bracket are more susceptible to experiencing complications from the flu and one single dose of the vaccine may not be enough to build their immunity for flu season. The CDC warns, "Children 2 years of age up to their 5th birthday are more likely than healthy older children to be taken to a doctor, an urgent care center, or the emergency room because of the flu."

Children within this age bracket who are being vaccinated for the first time or who had only one flu shot last season should get two doses of the vaccine. The CDC recommends obtaining the second dose at least 28 days after the first dose has been given. The first dose primes the child's immune system while the second dose provides immune protection for the season. Since this process takes longer and the flu shot doesn't begin protecting against the illness until two weeks after it's administered, take your child in early. Consider getting your child's first flu shot as soon as the vaccines become available for the season.


You had Guillain-Barré Syndrome in the past

woman suffering from pain in bone

The CDC defines Guillain-Barré Syndrome (GBS) as "a rare disorder where the body's immune system damages nerve cells, causing muscle weakness and sometimes paralysis." This disorder usually occurs directly after a person has been infected by a virus or bacteria. In the U.S., about 3,000 to 6,000 people develop GBS each year. While most people recover from this disorder, some may suffer permanent nerve damage.

After the swine flu vaccination in 1976, there was a small increase in the number of GBS cases. The recorded increase was one additional case for every 100,000 people who received the vaccine. After this increase, the CDC began to monitor a link between the flu vaccine and GBS. It found that each year, the number of cases generally increase by one or two per 100,000, if any.

If you contracted GBS after your flu shot last year or you recently had this disorder, GBS/CIDP Foundation International suggests that, "discussing this matter with the primary physician is likely the best means to assess a vaccine's value." Visit your primary care doctor first to weigh the pros and cons of obtaining a flu vaccine if you've ever suffered from GBS in the past. For more ways to be happier and healthier, don't miss this essential list of the 40 Health Warnings You Should Never Ignore.

Kelly Hernandez
Kelly Hernandez is a health and wellness writer and certified personal trainer. Read more about Kelly