After mild flu seasons in 2020 and 2021, this year may be a doozy.
Researchers look to the Southern Hemisphere to identify potential influenza severity and circulating virus strains, as the flu season Down Under happens months before ours. And this year, Australia “had one of their worst flu seasons in the past five years,” says Annabelle de St. Maurice, MD, MPH, co-chief infection prevention officer for UCLA Health.
The precautions we took to prevent spreading COVID-19 — wearing masks, physical distancing — likely contributed to the low number of influenza cases the past two years, Dr. de St. Maurice says. But as people mingle more, transmission of common respiratory viruses (such as enterovirus and respiratory syncytial virus) is increasing, she says, “and we’ll probably see the same trend with flu this year.”
Such conditions make getting a flu vaccine essential, doctors say.
“Everybody should get a flu shot,” says Dr. de St. Maurice. “It’s a very safe vaccine. It’s recommended for anybody 6 months of age or older. And it’s very essential for people who have health conditions that put them at higher risk.
"There are very few contraindications to flu vaccine," she says. "Even with a mild egg allergy, you can still get the flu vaccine."
The vaccines are manufactured three different ways, including an egg-based and a cell-based version. The third is a recombinant flu vaccine, which is created synthetically.
Flu vaccines are offered every fall to protect against severe illness during flu season, which generally runs from October to February. Flu vaccination rates in California dropped slightly from 2019 to 2021 – from 51% to 49% – according to the U.S. Centers for Disease Control and Prevention.
While vaccination against influenza does not prevent all flu infections, it reduces the likelihood of the need for doctor visits related to the virus by 40% to 60%, according to the CDC. Vaccination significantly reduces hospitalization for flu for all age groups. And the flu vaccine can be life-saving for children, with a 2022 study finding it reduced the risk of life-threatening influenza by 75%.
Even young and healthy individuals can get severely ill from flu, Dr. de St. Maurice says, recalling an unvaccinated, athletic patient in his late teens who ended up on a ventilator after coming down with the virus.
Don’t let ‘vaccine fatigue’ stop you
Dr. de St. Maurice acknowledges people may be experiencing “vaccine fatigue,” as we simultaneously consider COVID-19 vaccines, booster shots and the new booster authorized in September to better match the circulating omicron variant.
“People are tired of hearing about the vaccines,” she says. “There might be some component of vaccine fatigue. But I don’t think that because we have all of these boosters and bivalent vaccines out for COVID that the flu vaccine is any less important.”
People age 12 and older, in fact, can get their flu shot and new COVID-19 booster at the same time.
“There doesn’t seem to be a problem with combining vaccines,” says Otto Yang, MD, a professor in the Departments of Medicine and Microbiology, Immunology and Molecular Genetics at the David Geffen School of Medicine at UCLA who has been studying COVID-19 since the virus emerged.
The COVID-19 booster is authorized for people 12 and older who’ve completed a primary vaccine series or received a booster at least two months prior.
Enhanced flu vaccines for older adults
“It’s important to make sure you have the most up-to-date version of the flu vaccine,” says Dr. de St. Maurice, as the formulation changes annually.
But not all of the available flu vaccines are the same.
People age 65 and older should receive a flu vaccine designed for older adults, Dr. de St. Maurice says.
“Adults over 65 have a less-robust response to vaccines than younger adults, which is why we have different formulations and different recommendations for adults for flu vaccine,” she says.
There are two options for people older than 65: the adjuvanted flu vaccine and the high-dose flu vaccine. The adjuvanted vaccine contains an additional ingredient to prompt a more robust immune response, while the high-dose vaccine contains four times the amount of antigen – which stimulates immune response – than typical flu vaccines.
Studies comparing high-dose and adjuvanted flu vaccine show they are equally safe in seniors and more effective than standard-dose flu vaccines, Dr. de St Maurice says.
“Both of these are associated with a more robust response in older adults and are preferentially recommended for adults over 65 years of age,” she says. “But if for some reason your pharmacy or clinic can’t get either of those or runs out, it’s still better to get a flu shot if you’re over 65 than to not get it.”
Prevention and treatment
Besides vaccination, other preventive measures for flu include frequent hand washing, wearing a mask in crowded places during flu season and staying away from others when you are sick.
If you do get sick, there are antiviral treatments for both flu and COVID-19.
Symptoms of the two viruses can be similar and include fever, body aches, sore throat, cough, runny nose and fatigue.
“If you have flu-like symptoms, it’s important to reach out to your primary care doctor, because you can get treated for flu,” Dr. de St. Maurice says. “We have paxlovid for COVID and we have baloxivir and oseltamivir for flu.”
These antiviral medications are most effective when taken as close to the onset of symptoms as possible, she says.
Find out how to schedule your flu shot.