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Flu Guide: What to Know This Season

Which Flu Shot is Best For You?

Getting the strongest protection for your age group could be especially important this year, doctors say

man getting a vaccine from a nurse both wearing masks

FG Trade/Getty Images

En español | If you were one of the 80 percent of people age 65 and older who lined up for a flu shot last year, public health experts want you to keep up the good work this fall.

But as you make your appointment or arrive at the clinic, there’s one more thing you should do for the best protection available: Ask for a either a high-dose or an adjuvanted vaccine. While experts say a standard flu shot is certainly better than no flu shot, these two options are designed to compensate for the weaker immune response that comes with age, making your vaccination more effective. 

All about the high-dose shot

The first option, the Fluzone High-Dose is an injectable flu vaccine that has been approved by the Food and Drug Administration (FDA) for folks over the age of 65 for more than a decade. It contains four times the antigens (the flu proteins our immune system recognizes and attacks) of a regular flu vaccine. As of last year, the shot is also quadrivalent, which means it offers even more protection because it protects against four strains of the virus, not just three.

Getting this high-dose vaccine “is very important for older adults, who are more susceptible to flu complications, both because of the decreased immunity that comes with age and also because they are more likely to have other coexisting health conditions, such as heart disease or type 2 diabetes, that leave them more vulnerable to the flu’s ill effects,” explains William Schaffner, M.D., an infectious disease specialist at the Vanderbilt University School of Medicine.

In any year, 50 to 70 percent of flu-related hospitalizations occur among people age 65 and older, according to the Centers for Disease Control and Prevention (CDC). “More protection from a high-dose shot could be really important for older people in particular right now, to keep them out of overfilled hospitals,” says Schaffner, referring to the possibility that hospitals will face a daunting season of combined flu and COVID-19 cases.

Research on the high-dose shot backs this up. A study published in The Lancet Respiratory Medicine reported that people 65 years and older who got Fluzone High-Dose had a lower risk of hospital admission compared with people in that age group who got the standard-dose Fluzone, especially those living in long-term care facilities. There’s also some evidence that the high-dose shot might help protect those over 65 from contracting COVID-19.

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An “adjuvanted” shot also adds protection

The second type of flu shot approved for people over age 65 is the adjuvanted flu vaccine (Fluad Quadrivalent). It’s made with something called the MF59 adjuvant, which is an additive that creates a more robust immune response. “It wakes up your immune system, so that it responds better to the vaccine,” says Schaffner.

A 2020 study published in The Journal of Infectious Disease showed that both Fluzone (high dose) and Fluad (adjuvanted) are effective in preventing the flu and flu-related hospitalizations among older adults. When it comes to the two shots for older adults, “It’s honestly six of one, half a dozen to the other,” adds Schaffner. “It really boils down to what your doctor’s office or pharmacy has.”

When to get your shot

The best time to get your shot is from mid-September through October, with the goal of hitting the sweet spot between being early enough to ensure your body has time to build up immunity and late enough in the season to make sure immunity doesn’t wear off by March or April, says Ronan Factora, M.D., a geriatrician at the Cleveland Clinic’s Center for Geriatric Medicine. Factora also recommends you consult with your physician about timing, as peak flu season may vary from one part of the country to another.

Also try to schedule the shot in the morning when possible. A 2016 study published in the journal Vaccine found that adults over 65 who were given vaccines between 9 and 11 a.m. had higher levels of protective antibodies than those given the shot between 3 and 5 p.m.

Yes, you may have a sore arm

Don’t be surprised if you notice more side effects — like an especially tender arm — after your flu vaccination. “It tends to be a little more sore after a high-dose shot because you’ve put in four times as much flu vaccine,” points out Schaffner.  But try to skip the over-the-counter pain relievers, as research suggests they may dilute the shot’s effectiveness.

You can also get the high-dose shot at the same time as you get your COVID-19 booster — there’s no reason why you need to space them out, doctors say — but just be aware that you may end up with two sore arms.

Shortages aren’t expected

All flu vaccines, including the high-dose one, are free with Medicare Part B. While in the past, there have been reports of vaccine production problems leading to vaccine shortages, this year manufacturers have projected that they will supply the United States with as many as 188 million to 200 million doses of influenza vaccine for the 2021–2022 flu season, and they’re not anticipating any delays, according to the CDC.

Remember: It’s never too late to get the vaccine, even once the flu season starts. “The flu usually peaks until February and then can circulate until April,” Schaffner adds. Just realize that even if you do get jabbed, you still need to take preventive steps like wearing a mask, practicing social distancing and washing hands frequently to protect yourself against both flu and COVID-19.

Editor’s note: This article was published on Sept. 16, 2020. It was updated in September 2021 with new information about the 2021-2022 flu season.

Hallie Levine is a contributing writer and an award-winning medical and health reporter. Her work has appeared in The New York Times, Consumer Reports, Real Simple, Health, and Time, among other publications.