Why It's So Important to Get Your Flu Shot and the Best Time to Get It

While the COVID-19 vaccine may have taken center stage the last few years (and for good reason), the flu shot has been (and still is) a crucial annual ritual.

According to flu statistics, the virus kills hundreds of thousands of people every year. And with COVID-19 still circulating, there continues to be a risk of co-infection, which can be risky for even the healthiest people.

Bottom line: The flu shot is important for everyone. Read on to learn more about its effectiveness, when to get a flu shot and other things to expect from the jab.

In the past, many of us haven't lined up to get the vaccine. During the 2022-2023 flu season, for example, less than half of all adults (47 percent) even bothered to get jabbed, according to the Centers for Disease Control and Prevention (CDC).

One of the reasons, says Margot Savoy, MD, MPH, senior vice president for education for the American Academy of Family Physicians, is the belief that the flu shot isn't effective.

It's true that a flu shot won't offer you total protection: For example, in the 2022-2023 flu season, vaccine effectiveness was about 54 percent, per the CDC. (It's typically between 40 and 60 percent effective, per the CDC.)

But research shows that getting the vaccine can make a big difference in the grand scheme of things.

During the 2021-2022 flu season, for example, people vaccinated for the flu had a 26 percent lower risk of intensive care unit admission at the hospital and a 31 percent lower risk of death from flu compared to those unvaccinated, per the CDC.

An August 2022 study in ‌Clinical Infectious Diseases‌ found that flu vaccination reduced children's risk of severe, life-threatening influenza by 75 percent.

Plus, according to a June 2021 ‌Vaccine‌ review, getting jabbed lowers your risk of death from the flu by nearly a third.

This is particularly key for older adults and people who are pregnant, both of whom are especially vulnerable to the flu, William Schaffner, MD, an infectious disease specialist at the Vanderbilt University School of Medicine, tells LIVESTRONG.com.

Flu vaccines have reduced the risk of flu-associated hospitalizations among both groups by about 40 percent, per the CDC.

"While the shot can't completely protect against the disease, it does offer some immunity, so if you do get it, your symptoms will most likely be less severe," Dr. Schaffner adds.

While it is possible to have an allergic reaction to a flu shot, it's very, very rare — only 10 cases of life-threatening anaphylaxis have been recorded for more than 7.4 million doses of flu vaccine given, according to the CDC.

In fact, starting in the 2023-2024 season, additional safety measures (beyond the typical measures for everyone) are no longer recommended for people with egg allergies getting the flu vaccination, per the CDC.

"You've got a much greater chance of being hospitalized or dying from the flu than having an allergic reaction to it," Dr. Savoy says.

In general, the best time of year to get the flu shot is early fall (i.e., around the end of October), according to the CDC. This gives your body a couple weeks to develop immunity before flu really hits, while also being late enough to make sure immunity doesn't wear off completely by March or April, Dr. Schaffner says.

In other words, the shot's protective effects wane over time, so you want to time things right in order to get the best protection during peak flu season.

Of course, flu patterns can vary a bit depending on where you live. It may be helpful to check out the CDC's map of flu activity by state during the past 12 months to get a sense of when the flu is most prevalent in your area.

If you miss the mark, don't panic — you can still reap the benefits of a flu vaccine later in the season. Even January or February isn't too late to get vaccinated, because the flu tends to circulate through early spring.

"It's true that seasonal flu usually peaks between December and March, but it can occur as late as May," Dr. Schaffner says, adding that he has vaccinated patients through April.

The good news is that it's very easy to get a flu shot. It's available not only at your doctor's office, but also at most pharmacies, city health departments and even local Planned Parenthood clinics. (To find the location nearest you, check the VaccineFinder website.)

Once you've made an appointment, you should be able to fill out any paperwork online in advance. This will help cut down on the time you have to spend in the doctor's office or pharmacy.

During peak flu season, there may be lines and wait times at the pharmacy to receive your flu shot. But if you complete your paperwork online in advance, that should help make the process as speedy as possible.

Contrary to popular belief, the flu shot won't give you the flu.

"The shot itself has enough of the virus — or proteins that mimic the virus — to cause your body to have a reaction, though," Dr. Savoy says.

Usually, that means nothing more than some soreness, redness and swelling at the spot where the shot was given, but some people may develop a low-grade fever, headache and body aches that can last for a day or two.

"It just means that your body is doing what it's supposed to do," she adds.