When's the best time to get a flu shot? What kind should I get?

Sept. 7, 2023 4 AM PT

Flu season is just around the corner, and the time is fast approaching for residents to consider getting their annual vaccine.

While the flu is often relatively mild, infection can carry dangerous — and even deadly — consequences for some. And that risk is one of the major reasons health officials encourage most everyone to roll up their sleeves and try and stymie the spread.

Here’s a primer on flu shots, based on information shared by the U.S. Centers for Disease Control and Prevention:

When is the best time to get a flu shot?

September and October are ideal times to get the flu shot. But if you miss that window, it’s still helpful to get it later in the cold-and-flu season, even through January or later.

What kind of flu shot should I get?

Health officials suggest that those age 65 and older get either a higher-dose or “adjuvanted” flu shot. An adjuvant is an ingredient that helps create a stronger immune response.

When it comes to the flu vaccine, there are three types that are recommended for older people, all with long, complicated names: HD-IIV4, or quadrivalent high-dose inactivated influenza vaccine; RIV4, or quadrivalent recombinant influenza vaccine; and aIIV4, or quadrivalent adjuvanted inactivated influenza vaccine.

But don’t sweat it if none of those are available. The CDC says any other age-appropriate flu shot is also acceptable.

Who should get the flu shot?

Everyone age 6 months and older, with rare exceptions.

Can you get the flu shot and a COVID vaccine at the same time?

Yes.

Can you get the flu shot if you are sick with COVID-19?

People who are at least moderately sick with COVID-19 should wait until they’re recovered before getting a flu shot.

And for people who are mildly ill or have no symptoms, a person might want to wait “to avoid confusing illness symptoms with vaccine reactions,” the CDC said.

If I’m going to travel, how soon should I get the flu shot for it to be fully effective on my trip?

Ideally, get the flu shot two weeks before leaving for the trip.

Is there an alternative to a flu shot?

Yes, there’s a nasal spray flu vaccine, which can be given to healthy people between the ages of 2 and 49. The spray is not an option for those who are pregnant, however, or for people with weakened immune systems.

Should pregnant people get the flu shot?

Yes. Getting vaccinated for flu helps protect pregnant people from becoming seriously ill, while also helping protect the baby from infection for a number of months after birth.

Can the flu shot give me the flu?

No, it’s impossible for a flu shot to give you the flu. Flu shots are made using either killed flu viruses or don’t contain any virus at all.

The nasal spray flu vaccine does contain weakened viruses, but they do not cause flu illness and are designed not to multiply in relatively warm places like the lungs.

Why are flu shots needed every year?

There are different kinds of flu, and the flu shot is reformulated annually to protect against the dominant versions expected to circulate each autumn and winter. Your immune protection from the flu, given through the flu shot, also weakens over time.

Seasonal vaccines are designed to protect against both infection and illness. Studies indicate that getting vaccinated against the flu reduces the risk of illness by between 40% and 60%, the CDC says. One study, published in 2018, suggested that adults who got a flu shot reduced their risk of getting admitted into an intensive care unit by 82%.

Why should I consider getting the shot?

The flu is no mere cold. Generally, the flu is more severe and can cause an abrupt onset of symptoms — including fever, aches, chills, fatigue, weakness, chest discomfort, cough and headache — that are sometimes serious enough to require a hospital stay. Flu can also be associated with serious complications like bacterial infections.

Recovering from flu can take days or even a couple of weeks, “but some people will develop complications (such as pneumonia) as a result of flu, some of which can be life-threatening,” the CDC says. Flu can also trigger inflammation of the heart, brain or muscle tissues.

Over the decade that ended with the 2019–2020 season, an average of about 35,000 Americans died from the flu annually.

Who is most at risk?

People at highest risk from flu include people older than 65; those with chronic health conditions like asthma, diabetes, or heart disease; pregnant people; and children younger than 5, especially those younger than 2.

But even young, relatively healthy people can fall seriously ill. And, officials note, they can unwittingly spread the flu to someone who is less equipped to fight off the infection.

What other viruses should I be aware of?

Flu presents a recurring, if somewhat predictable, healthcare challenge. But last year saw an unusual convergence — a ‘tripledemic’ when flu season arrived at the same time as an onslaught of respiratory syncytial virus, or RSV; as well as a resurgence of COVID-19.

Hospitals were quite strained last autumn and winter due to respiratory illnesses. Initial estimates suggest there were somewhere in the range of tens of thousands of flu deaths nationally, along with hundreds of thousands of flu hospitalizations.

This year, protection against RSV for the first time is available in the form of vaccinations for people age 60 and older and monoclonal antibodies for babies and young children, which are recommended before a possible infection. Administration of those could help reduce the impact of RSV this year.

Updated COVID-19 vaccines — formulated, like the flu shots, in hopes of providing protection against the dominant circulating strains — are also expected to be available, perhaps as soon as next week.