Flu Season Off to Worst Start in 13 Years

Learn why experts advised Americans to brace for a doozy, and how COVID and RSV have complicated things.

close up of vaccination in arm

Medically reviewed in November 2022

Updated on December 12, 2022

Flu season got off to an early start in the United States, fueling concerns about what lies ahead. Since October 1, it’s estimated that there have been at least 8.7 million cases of the flu and up to 170,000 people have been hospitalized as a result. The virus has also claimed at least 4,500 lives, including 14 children, the Centers for Disease Control and Prevention (CDC) reports as of December 2. 

Flu typically starts to spread in October, but it usually doesn’t peak until a few months later. Flu season hasn’t been this bad, this early in more than a decade.

Why did this happen—and what does this mean for the weeks ahead?

While all eyes were on COVID over the past few years, flu was off the radar for many people. But this year, things have changed.

Australia just had its worst flu season in five years. Case rates were three times higher than average, peaking about two months earlier than usual. Why does this matter for the United States? Flu season in the Southern Hemisphere starts in April and lasts until September, while it spans October to May in the Northern Hemisphere. So, flu season in Australia is ending just as it’s about to begin in the United States.        

U.S. health officials monitor what happens in the southern hemisphere to help predict what’s in store for the northern hemisphere. In other words, if Australia just had a bad flu season, chances are we’re next.

Meanwhile, after several weeks of declines in COVID infections in the U.S., there has been an uptick in counties with a medium or high level of disease activity. More than 4,800 people are still being hospitalized for COVID each day.

And just as flu season was getting underway, RSV cases jumped. RSV is another seasonal virus that also tends to spread in the fall and winter months. Anyone can get RSV and most kids are infected by the age of 2, but research suggests that COVID precautions over the past few years have led to an “immunity gap”— an increase in vulnerable new babies and reduced immunity from lack of exposure to the virus.

Like flu, most people with RSV recover within a couple weeks. But for some people, the infection can be more serious and lead to complications. While there is no vaccine yet to prevent RSV, there are vaccines to help protect against the flu—and COVID.

The CDC recommends that nearly everyone aged 6-months or older receive a flu vaccine each year. The CDC reports that this year's flu shot is a good match for most viruses in circulation. 

September and October are the best months to get vaccinated against the flu. Ideally, everyone should get their shot by the end of October. But it’s never too late. That goes for children, too. Kids 6-months or older are eligible. In fact, Lynette Brammer, leader of CDC's Domestic Influenza Surveillance team, says "very consistently year to year" about 80 percent of flu deaths among children involve kids who are not vaccinated. 

And for people older than 65, high-dose flu vaccines are recommended. These high-dose shots can help older people develop a stronger immune response against the flu. 

And if you also need a COVID vaccine (whether it’s your first, second or the updated booster), the CDC says you can get it at the same time as your flu shot. That means you don’t have to choose between protecting yourself from COVID or the flu.

Last flu season was mild

In 2020 and 2021, as the cold months approached, health officials worried a bad flu season could compound the nation’s COVID pandemic. Some warned that a “twindemic” could further strain health care resources.

Thankfully, that didn’t happen. The nation saw mild flu seasons for the past two years. The same measures that protect people from COVID—masking, distancing, working at home—likely helped ward off the flu.

But now that most COVID protection policies are no longer in effect, flu seems to be making a comeback.

Why we're having a bad flu season this year

Australia’s doozy of a flu season isn’t the only hint of what’s to come. Some researchers anticipated a severe flu season because, overall, flu immunity might be lower than usual since so few people caught it for the past two years.

Flu may not seem scary, but it can be deadly. The CDC estimates that since 2010, influenza has resulted in between 9 million and 41 million illnesses, between 140,000 and 710,000 hospitalizations and between 12,000 and 52,000 deaths each year.

Getting a flu shot can help save lives. Don’t be deterred by the fact that the flu vaccine isn’t a perfect shield (its average efficacy is about 40 percent to 60 percent).

The percentage of people who get the vaccine is far more important to public health than its efficacy. For example, a flu vaccine that’s only 20 percent effective could still save nearly 62,000 lives if 43 percent of the population got one, a 2018 study published in Proceedings of the National Academy of Sciences found. Boost that vaccination rate to 50 percent of the population, and nearly 8,500 additional flu deaths are avoided.

Timing your flu shot and COVID vaccine

Whether you’ve already been immunized against COVID and are eligible for a booster, or you’re ready for your first dose, the CDC advises that you can get a flu shot at any time—even on the same day.

There is now abundant research on the safety of the COVID vaccine. And in addition to what we already know about how flu vaccine behaves when given with a variety of other vaccines, the CDC is confident that giving COVID shots at the same time as other vaccines is both safe and effective.

The CDC also says that side effects are about the same whether a vaccine is given alone or at the same time as other vaccines. (Children and people about to travel abroad, for example, routinely get multiple vaccines on the same visit without incident.) Some data from other studies of flu vaccination along with other vaccine types have suggested higher rates of adverse reactions when the flu vaccine is given with others, but these reactions have been mostly mild to moderate.

One caveat: some flu vaccine types are likely to trigger a stronger immune response that could lead to, say, a sore and tender muscle. The CDC advises providers who are simultaneously giving COVID shots and other shots that are more prone to lead to that kind of localized reaction to inject them on different arms. (If given on the same arm, the two injections should be spaced at least one inch apart.)

Bottom line? For most people, it’s safe to get immunized against both the flu and COVID at the same time—and it’s wise not to wait. It’s the best way to protect yourself and others from infection in the coming months. The CDC also notes that even if it's not required, masking up—especially in crowded, indoor spaces with poor ventillation—is another step people can take to help protect themselves from the flu, RSV, COVID, and other respiratory infections. 

Article sources open article sources

Centers for Disease Control and Prevention. 2022-2023 U.S. Flu Season: Preliminary In-Season Burden Estimates. Oct 28, 2022.
Centers for Disease Control and Prevention. Weekly U.S. Influenza Surveillance Report. Oct 28, 2022.
Centers for Disease Control and Prevention. COVID Data Tracker Weekly Review. Oct 28, 2022.
Centers for Disease Control and Prevention. COVID Data Tracker. Accessed Nov 2, 2022.
Kevin Messacar, Rachel E Baker, Sang Woo Park, et al. Preparing for uncertainty: endemic paediatric viral illnesses after COVID-19 pandemic disruption. The Lancet. Jul 14, 2022.
Centers for Disease Control and Prevention. Respiratory Syncytial Virus Infection (RSV). Oct 28, 2022.
Australian Department of Health and Aged Care. Australian Influenza Surveillance Report and Activity Updates, Sep 16, 2022.
Centers for Disease Control and Prevention. Frequently Asked Influenza (Flu) Questions: 2021-2022 Season. May 26, 2022.
Centers for Disease Control and Prevention. “Weekly U.S. Influenza Surveillance Report.” Nov 6, 2021.
Centers for Disease Control and Prevention. “Weekly National Flu Vaccination Dashboard.” Nov 3, 2021.
Centers for Disease Control and Prevention. “2020-2021 Flu Season Summary.” Updated July 22, 2021.
Centers for Disease Control and Prevention. “Frequently Asked Influenza (Flu) Questions: 2021-2022 Season.” Last reviewed Sep 1, 2021.
Centers for Disease Control and Prevention. “CDC COVID Data Tracker.” Sep 14, 2021.
Associated Press. “Crowded stadiums, pandemic create combustible mix this fall.” Sep 11, 2021.
Deloitte. “Executives share their plans for returning to the workplace.” Accessed Sep 13, 2021.
The New York Times. “Reopening Plans for the 100 Biggest School Districts Are Changing Fast.” Aug 13, 2021.
Statista. “Year over year retail foot traffic change during the coronavirus (COVID-19) outbreak in the United States in 2020 and 2021, by week.” Apr 2021.
CNBC. “Health experts are anxious to prevent a ‘catastrophic’ winter flu season.” July 7, 2021.
Krauland MG, Galloway DD, Raviotta JM et al. Agent-based Investigation of the Impact of Low Rates of Influenza on Next Season Influenza Infections. medRxiv 2021.08.18.21262185.
Centers for Disease Control and Prevention. “Disease Burden of Influenza.” Last reviewed June 11, 2021.
Lazarus R, Baos S, Cappel-Porter H et al. The safety and immunogenicity of concomitant administration of COVID-19 vaccines (ChAdOx1 or BNT162b2) with seasonal influenza vaccines in adults: a phase IV, multicentre randomised controlled trial with blinding (ComFluCOV). The Lancet preprint.
Lee K, Jalal H, Raviotta JM et al. Predicting the impact of low influenza activity in 2020 on population immunity and future influenza season in the United States. medRxiv 2021.08.29.21262803.
Centers for Disease Control and Prevention. “Flu Vaccination Coverage, United States, 2019–20 Influenza Season.” Oct 1, 2020.
Sah P, Medlock J, Fitzpatrick MC et al. Optimizing the impact of low-efficacy influenza vaccines. Proc Natl Acad Sci U S A. 2018;115(20):5151-5156.
Centers for Disease Control and Prevention. “Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Approved or Authorized in the United States.” Last updated Aug 31, 2021.
Grohskopf LA, Alyanak E, Ferdinands JM et al. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices, United States, 2021–22 Influenza Season. MMWR Recomm Rep 2021;70(No. RR-5):1–28.

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