When is the best time to get a flu shot? Here’s what doctors say.

Fall season usually means the start of people wearing cozy sweaters, sipping pumpkin spice lattés — and getting the flu.

It’s something most people haven't had to deal with for the past couple of years because of the pandemic. During the 2020-2021 flu season, flu activity was “unusually low,” according to the Centers for Disease Control and Prevention (CDC), thanks to COVID safety measures, such as more people wearing masks, upping their hand washing hygiene and staying home.

However, as life has started returning to normal for many, flu cases are expected to climb this fall and winter, which is why experts recommend getting the flu vaccine.

But when exactly should you get one? And can you get a flu shot at the same time as the Omicron booster? Here’s what experts say.

First, why do people need a flu shot each year?

The flu is actually caused by several different influenza viruses. The two types of viruses responsible for most people getting seasonal flu are influenza A and influenza B, and they each have their own subtypes and groups.

Because flu viruses are constantly changing, along with the fact that immunity wanes over time, the flu vaccine is reformulated each year for better protection. There’s even an organization — The World Health Organization’s Global Influenza Surveillance and Response System, which was established in 1952 — that monitors the frequent changes in influenza viruses.

Dr. Pedro Piedra, professor of molecular virology and microbiology and of pediatrics at Baylor College of Medicine, tells Yahoo Life that it’s a “good surveillance network globally that looks at what viruses are circulating, and then they formulate the best guess as to what needs to be changed in the vaccine” for that year.

Piedra explains that, generally, the vaccine will have an “almost perfect match” with one of the strains that’s circulating. He adds: “It’s always hard to have a perfect vaccine for all of the viruses that are circulating. But you don’t always have to have a perfect match to have cross protection.”

How effective is the flu vaccine?

Flu vaccines have been shown to reduce the risk of having to go to the doctor with flu by 40% to 60%, according to the CDC. “Flu shot reduces the risk of severe flu symptoms, hospitalization, ICU admission and death,” Dr. Riza Conroy, a family medicine physician at the Ohio State University Wexner Medical Center, tells Yahoo Life.

The vaccine can also help protect those who are the most vulnerable to complications from flu viruses, which typically target children 6 months to 5 years old, as well as adults age 65 and older, according to the Mayo Clinic. In fact, the CDC states that flu vaccination can be “lifesaving” for children. A 2022 study found that flu vaccination reduced children’s risk of life-threatening influenza by 75%.

“Children can also die from flu,” says Piedra. “Generally, the children who have died from flu have been children that have not been vaccinated.” He adds that “it’s not only older folks” that can die from the flu. “Children have a greater risk of more severe complications, just like pregnant women do.”

When is the best time to get a flu shot?

Although influenza viruses are detected year-round, they circulate more widely during the fall and winter months. Conroy points out that flu season “peaks December to February but has been seen to go up in cases around March, too, and may still be noted all the way to May.”

According to Conroy, “The best time to get the flu vaccine is around October” so you’re protected for flu season, noting that the flu shot is “usually in full effect two weeks after receiving the vaccine.”

Peidra agrees that October is “a good month” to get vaccinated. But in general, experts say there’s no time like the present. “This year we’re already seeing flu activity,” says Peidra, “and it’s early.”

Flu vaccine is effective for about five to six months, notes Conroy.

Who should get a flu shot?

Everyone 6 months or older should get the flu vaccine that’s appropriate for their age, says Conroy, unless your health care provider indicates otherwise.

There are several flu vaccines approved for use in those as young as 6 months old and older, while there are two vaccines approved only for adults 65 years and older, according to the CDC. The nasal influenza vaccine, FluMist, is available for children and adults ages 2 to 49. It’s also worth noting that some children 6 months to 8 years old need two doses of flu vaccine.

Can you get the Omicron booster and flu shot at the same time?

Yes, say experts. “You can get the flu shot and Omicron booster at the same time. There is no contraindication giving both vaccines together,” says Conroy,

However, if you haven’t already gotten your recommended doses of the COVID-19 vaccine, the CDC recommends getting them as soon as possible, followed by a flu vaccine by the end of October.

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