“Schedule your flu shot” messages are popping up on billboards, on store facades and in crowded email inboxes. As COVID-19 continues to circulate, influenza (flu) is preparing to make its annual entrance, too.

The U.S. flu season can start as early as October and linger into May, peaking sometime in the dead of winter between December and February.

In a typical year, as many as 36,000 people in the United States die from flu.

The Centers for Disease Control and Prevention says while the 2021-22 flu season was pretty mild — probably because precautions against COVID-19 protected against flu — influenza A still lingered through mid-June. Healthcare providers were also alert for cases of avian flu.

The CDC says vaccination is the best way to avoid flu or at least harsh complications.

But how bad will the coming flu season be?

Predicting a bad year

Experts expect that flu could rage back at full force this fall and winter.

According to the LaCrosse Tribune, “While the CDC says the ‘timing, intensity and severity of the 2022–23 influenza season cannot be predicted,’ Dr. Abinash Virk, an infectious diseases specialist at Mayo Clinic Rochester, says the widespread return to pre-COVID habits is likely to lead to an uptick in infections.”

He said that practices like masking, social isolation and generally keeping a distance from others have virtually disappeared, so influenza spread is likely to be stronger.

The Lancet reported a “rapid rise in influenza A notifications in Australia, which started earlier than usual and as of (Aug. 3) are tracking at record high numbers.”

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The article said that early data from Australia helps predict what’s coming to the northern hemisphere this winter.

The study said the bulk of the cases “down under” were influenza A cases, “known to cause more severe epidemics.” And it noted that the drop in precautions against COVID-19 will likely contribute to more cases of flu, which will then be exacerbated by low flu vaccination rates there — and perhaps in the United States, too.

Flu symptoms and prevention

Influenza is a highly contagious respiratory illness and can lead to severe complications and even death. People with compromised immune systems and other chronic conditions, older folks, pregnant women and young children are at most risk.

Symptoms include fever and chills, cough, sore throat, runny or congested nose, muscle and body aches, headaches, exhaustion and sometimes vomiting and diarrhea — more common in kids than in adults, according to the CDC.

While fever is common, not everyone with flu becomes feverish, the agency says.

Flu spreads through respiratory droplets in the air or on surfaces and objects. People who touch those objects and then their own eyes, nose or mouth can be infected.

Each flu season, an average of 1 in 12 people get the flu. And it’s possible to spread it to others before you even know you have it, CDC says.

Complications can include pneumonia, ear infections, sinus infections and a worsening of some chronic medical conditions like heart failure and asthma.

Good hygiene is an important prevention tool, too: Covering coughs and sneezes, and consistent hand washing.

But health officials say nothing beats getting vaccinated each year against the flu.

About the vaccine

The federal government promotes vaccination against flu for those 6 months and older, with the exception of those with allergies to vaccine ingredients. Children 8 and under need two doses. And experts say September or October are ideal times to get the vaccine, though later is better than not at all.

The LaCrosse Tribune said “flu vaccines have a 40-60% effectiveness rate, per the CDC.”

An international network of laboratories collaborates on surveillance for influenza activity. Using that information and watching patterns of influenza circulation, the vaccine experts who are part of the Food and Drug Administration’s Vaccines and Related Biologic Products Advisory Committee consider the World Health Organization’s recommendation to decide what goes into the vaccine. Those factors form their best educated guess as to what type of flu will be present during an upcoming flu season. Most often, the guess is pretty accurate, though on occasion a flu strain that wasn’t expected surges.

The 2022-23 influenza vaccines uses the same formula used last year for the H1N1 flu variant, but made some changes in the H3N2 portion. Both of those are influenza A strains. The influenza B component was changed this year.

Healthline reported there are six vaccine options this year, including egg-free ones for those who are allergic, a nasal spray and higher potency versions for older adults. DrugTopics reported that in June, the Advisory Committee on Immunization Practices recommended that “all adults 65 and older receive high-dose influenza vaccines for better protection.”