The flu vaccine is surrounded by myths and misconceptions.
Every year, some people cite a myriad of myths and misconceptions as reasons they’re hesitant to get a flu shot, says Dr. Daniel McGee, a pediatric hospitalist at Helen DeVos Children’s Hospital in Grand Rapids, Michigan. McGee figures he’s heard them all, from “the flu shot will give you the flu,” to “I don’t need the flu shot because I already had the flu this year.”
In fact, the science is clear: the flu shot is safe and effective.
Influenza kills tens of thousands of people in the U.S. each year and causes hundreds of thousands of hospitalizations annually. Between 2010 and 2020, the flu caused 359,000 deaths in the U.S., according to Statista. “The best way to stay healthy and steer clear of the flu is to get vaccinated,” he says.
Here are nine myths and misconceptions about the flu shot:
1. The flu shot can give you the flu.
The flu vaccine won’t give you the flu. The virus contained in the injectable flu vaccine is what’s referred to as a “killed virus,” which is an inactivated, noninfectious form of the virus. Such vaccines typically don’t provide immunity that’s as strong as live virus vaccines, so you may require several boosters over time to achieve ongoing immunity.
In contrast, the virus in the nasal spray flu vaccine contains live viruses. However, they have been weakened so that they will not cause illness. The virus no longer has the ability to replicate and therefore can’t infect you.
If you feel a bit sluggish after receiving the vaccine, that’s because your immune system is kicking in, which is a good thing.
Most people experience only minor side effects from the shot, such as:
— Muscle aches.
— Soreness around the injection site.
— A light fever. A body temperature between 99.6 and 100.3 Fahrenheit is considered to be a low-grade fever.
2. I just got the COVID-19 vaccine, so I can’t get the flu shot.
It’s perfectly safe to get both the COVID-19 vaccine and the flu shot at the same time, according to the Centers for Disease Control and Prevention.
If you’re worried about possible side effects from one or both shots, waiting a week or two between vaccines is fine, McGee says. But don’t put it off too long. The sooner you get your flu shot, the earlier you’re protected.
3. The flu vaccine takes effect immediately.
It takes about two weeks after you receive your vaccination for your body to make the antibodies that protect you against infection from the influenza virus, says Dr. Jan K. Carney, associate dean for public health and policy and a professor of medicine at the Larner College of Medicine at the University of Vermont.
In the U.S. (and the rest of the northern hemisphere) influenza season usually spreads form October to March, peaking between December and February. That’s why the CDC recommends getting your flu shot every year in September and October.
“The flu shot isn’t perfect, the average effectiveness is 65%,” McGee says. “So you may still contract the flu, but if you do your case is likely to be much less severe.”
4. It’s too late to get the flu vaccine.
The CDC recommends getting the flu shot annually and as soon as it’s available, but it’s never too late in the flu season to get it, McGee says. “So even if it’s January, get the shot, particularly if influenza is active in your community,” he says. “Getting vaccinated well into flu season is better than not getting vaccinated at all.”
Keep in mind that it takes about two weeks for the vaccine to become fully effective.
5. Pregnant women shouldn’t get the flu vaccine.
Actually, it’s important for pregnant women to get the flu vaccine. Because of physiological changes that occur during pregnancy, pregnant women are more likely to experience severe illness from influenza than non-pregnant people, says Dr. Jasjit Singh, a pediatric infectious disease specialist and medical director of infection prevention and control at Children’s Health of Orange County in California.
Vaccination reduces the risk of flu-associated acute respiratory illness in pregnant women by half. It also cuts down the risk of hospitalization by 40%, according to research published in the journal Clinical Infectious Diseases in 2019.
In addition, vaccinations will pass antibodies onto the baby, protecting them from flu in those vulnerable first months of life.
Flu vaccines have been administered to millions of pregnant women with a good safety record. The CDC’s Advisory Committee on Immunization Practices recommends the flu shot for pregnant women.
6. I never get the flu, so I don’t need the flu vaccine.
Everyone, ages 6 months and older, should get the flu vaccine whether they previously had influenza or not, Singh says. “Viruses change, and transmission rates can vary with each season,” Singh says. “Just because someone was lucky enough to avoid the flu in the past doesn’t mean they aren’t at risk for getting in the future. It’s also important to think about herd immunity. The more people are vaccinated, the less likely for influenza to be passed to others.”
7. If you’re allergic to eggs, you can’t get the flu shot.
The CDC’s Advisory Committee on Immunization Practices says that people with egg allergies can get the current licensed, recommended and age-appropriate influenza vaccine, Singh says.
People who have a history of severe allergic reaction to eggs should be vaccinated in a medical setting under the supervision of a health care provider who can recognize and manage a severe allergic reaction. That’s because most flu shots and the nasal spray flu vaccine are manufactured using egg-based technology, according to the CDC. Therefore, they contain a small amount of egg proteins, an example being ovalbumin.
However, research suggests that using either the nasal spray vaccine or flu shots in people who are egg-allergic is unlikely to cause severe allergic reactions, according to the CDC.
For the 2020-2021 flu season, there are two vaccines licensed for use that are manufactured without eggs and are, according to the CDC, considered to be egg-free:
— Flublok Quadrivalent, licensed for use in adults age 18 and older.
— Flucelvax Quadrivalent, licensed for use in people age 4 and older.
A severe reaction could lead to anaphylaxis and cause symptoms including:
— Abdominal pain.
— Asthma signs (coughing, wheezing, shortness of breath).
— Rapid pulse.
— Severe drop in blood pressure.
8. Flu shots are only for kids and the elderly.
The CDC recommends a flu shot every year for everyone age 6 months and older. That’s because while most people fully recover from a flu infection in a week or so, some individuals suffer complications, such as ear and sinus infections or pneumonia, Carney says.
Adults age 65 and older and infants age 2 and younger are at risk of suffering serious complications from the flu.
Those complications include:
— Neurologc and neuro-development conditions.
— Blood disorders.
9. Nasal sprays are an effective alternative to the flu shot.
For some people, a nasal spray vaccine may be an alternative to the flu shot. The CDC recommends the nasal spray flu vaccine for people ages 2 though 49 who are healthy and not pregnant, Carney says.
However, in addition to children younger than 2 years old and people 50 years and older, there are people with certain chronic medical conditions who should not get the nasal spray vaccine, which contains weakened influenza viruses. When these weakened viruses are sprayed into the nose, they stimulate the body’s immune system to develop protective antibodies. Individuals with a weakened immune system shouldn’t get the nasal spray for flu protection. The CDC provides a list of these conditions.
If you can’t take a nasal spray vaccine because of a health condition, you can safely take any of the available flu shots, says Dr. Seth Cohen, director of Infection Prevention and Control at the University of Washington Medical Center in Seattle. If you feel uncertain, talk to your health care provider about which flu vaccine you should get.
9 myths and misconceptions about the flu vaccine:
— The flu shot can give you the flu.
— I just got the COVID-19 vaccine, so I can’t get a flu shot.
— It’s too late to get the flu vaccine.
— Pregnant women shouldn’t get the flu vaccine.
— I never get the flu, so I don’t need a flu vaccine.
— If you’re allergic to eggs, you can’t get the flu shot.
— The flu vaccine takes effect immediately.
— Flu shots are only for kids and the elderly.
— Nasal sprays are an effective alternative to the standard flu shot.
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Update 11/03/21: This story was previously published at an earlier date and has been updated with new information.
Correction 11/05/21: A previous version of this story misstated one of Dr. Jan K. Carney’s titles. She is an associate dean for public health and policy and a professor of medicine at the Larner College of Medicine at the University of Vermont.