Flu Shots: What You Need to Know

If there’s any good to come from the COVID-19 pandemic, it may be that more Americans understand just how vital vaccines are to public health.

The Centers for Disease Control and Prevention and health organizations and providers across the U.S. stressed the importance of getting a flu shot this past fall in order to prevent a “double whammy” of flu and coronavirus infection spikes. That effort has shown good results: As of mid-January 2021, 53% of all adults had received the flu vaccine according to CDC estimates, up from 45% by the end of January 2020. The hope is that flu vaccination rates will continue to remain high in the coming fall and all future falls, which is the best time to be immunized against the flu.

It helps to know as much as you can about the flu vaccine and why it is so important to get your flu shot every year.

[Read: Questions to Ask Your Doctor About the COVID-19 Vaccine.]

How the Flu Shot Works

The flu shot is made from a live but weakened virus, an inactivated (dead) virus or a recombinant molecule (created using DNA molecules). “All three cause the body to produce antibodies against the flu virus within approximately two weeks. These antibodies are then ready to fight live flu virus when the body encounters it,” says Dr. James Ellzy, a practicing family physician in Washington, D.C., and a member of the board of directors of the American Academy of Family Physicians.

The vaccine triggers your body’s immune system to realize “there is something in your system that shouldn’t be there,” says Dr. Tochi Iroku-Malize, a practicing family physician in Long Island, New York, and also a member of the board of directors of the AAFP. B cells, part of the white blood cells in your body that fight off infection, sense the virus particles and send out antibodies to attach to them and eliminate them before they cause harm.

In addition, your body’s T cells “are like the troops that check your cells to make sure they are not invaded by the virus. They also create memory so that your body is ready and waiting should you be exposed to the real virus at a future date,” says Iroku-Malize, who is also the founding chair and a professor of family medicine for the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell in Hempstead, New York, and chair of family medicine for Northwell Health. The nasal spray version of the vaccine is a weakened virus that activates your immune system in the same way, she says.

Why You Need a New Flu Shot Every Year

The viruses that cause influenza mutate every year, so each flu season presents new viruses that require new serum to fight it. Scientists try to anticipate what the viruses will look like months ahead of time, and create a new serum to fight off the top three or four contenders.

How Effective Is the Flu Shot?

The CDC reports that flu vaccination reduces the risk of having to go to the doctor with flu illness by about 40% to 60% in good years. Because the vaccine changes which strains of influenza are covered from year to year, “There are some good years where the predictions are correct, and others where a different strain or strains are more prevalent than predicted,” says Ellzy, who is also an assistant professor of medicine at Fort Belvoir Community Hospital, with the Uniformed Services University of the Health Sciences.

Even at 50% effectiveness, the flu vaccine prevents millions of illnesses and flu-related doctor’s visits each year. “During the last flu season, there were more than 100,000 flu-related hospitalizations, so prevention is very important. In children, the flu vaccine has been shown to reduce intensive care admissions by about 75%, and in the elderly by about 40%,” Iroku-Malize says.

[Read: Is It COVID-19, Allergies, Flu or a Cold?]

Who Should Get a Flu Shot?

Almost everyone should get a flu shot. In fact, the list of people who should not get the flu vaccine is very short. There are different flu vaccines for different groups of people, beginning at 6 months of age. The vaccine is also generally safe and beneficial for pregnant women and people with certain chronic health conditions. And it is safe for most people who have an egg allergy — the vaccine is manufactured with egg. You should always talk to your doctor before getting the shot, in particular if you have any serious allergies.

When Should You Get a Flu Shot?

Seasonal flu usually begins in the fall and peaks in the winter, and sometimes it may last until late spring. It takes about two weeks for the antibodies produced by the vaccine to build up and protect you after the vaccine is given, so the ideal time to receive the flu vaccine in the U.S. is September or October. “But since flu season extends almost to spring, it is often still available in February and March,” Ellzy says. “Flu season may be at different times in other parts of the world.”

Children who require two doses should start earlier than the rest of the population, because those doses need to be given a month apart, Iroku-Malize says. “This applies to children who are 6 months to 8 years old if they are getting the flu vaccine for the first time or if they have only had one dose in the past.”

What Are the Side Effects?

Some people have no side effects at all, and some may have mild symptoms such as soreness, redness and swelling at the site the shot is given. Others may experience headache, fatigue, a cough and nausea. Children may experience wheezing, muscle aches, vomiting and low-grade fever. Symptoms usually resolve on their own within a few days. Severe allergic reactions are very rare.

[Read: Here’s What You Should Eat to Fight Off Colds and the Flu.]

What Else Should You Know About Flu Shots?

Iroku-Malize stresses the importance of getting the flu vaccine every year, because the protection from your body’s own antibodies decrease over time and the flu viruses change year to year. “As long as the coronavirus is around, the flu vaccine will help reduce hospitalizations for the flu, which allows the health care system to better provide care for those with COVID-19,” she adds.

Most importantly, getting vaccinated for the flu will help protect you, your family, friends, colleagues and community from what can become a very serious illness. “Getting a flu shot can save the life of you or a loved one,” Ellzy says. “People die every year from influenza.”

More from U.S. News

14 Myths and Misconceptions About the Flu Vaccine

Myths About Your Immune System

Questions Doctors Wish Their Patients Would Ask

Flu Shots: What You Need to Know originally appeared on usnews.com

Related Categories:

Latest News

More from WTOP

Log in to your WTOP account for notifications and alerts customized for you.

Sign up