Flu Guide: What to Know This Season
En español | As colder weather approaches, infectious disease experts are worried that more people spending more time indoors will lead to not only an increase in COVID-19 infections, but more cases of the flu, too. But here's the good news (yes, some good news): The flu season in the Southern Hemisphere has so far been surprisingly mild. Why that matters? That season, which runs from April to September and peaks in August, is used as a bellwether for what to expect here a few months later. And according to the World Health Organization (WHO), countries below the equator have experienced a record-low flu season.
When WHO collected data on almost 200,000 flu tests conducted by laboratories across the world during the first half of August, only 46 were positive for the influenza virus. Australia itself only reported just over 21,000 cases of flu by the end of August, compared to over a quarter-million at the same time in 2019.
One big reason, notes William Schaffner, M.D., an infectious disease specialist at the Vanderbilt University School of Medicine, is that the flu season in the Southern Hemisphere started shortly after COVID-19 hit. “All those precautions people were taking to avoid the novel coronavirus, like social distancing, wearing masks, and practicing good hand hygiene, are also key to preventing flu as well,” he explains.
The other key factor in this year's flu season is the fact that many more people got flu shots. In Australia, for example, a record 18 million flu vaccines were available, compared to just over 13 million in 2019. As of the end of May, over 7.3 million Australians had already gotten their jabs, compared to just 4.5 million a year earlier. While it's true that a flu shot won't offer you total protection — a Centers for Disease Control and Prevention (CDC) report released this past February found that this past year's shot was only about 45 percent effective at preventing an infection — those who get one are less likely to spread it to others and less likely to experience complications, says Kenneth Koncilja, M.D., a geriatrician at the Cleveland Clinic. This, he notes, also adds up to less stress on an already taxed hospital system.
But experts stress that just the Southern Hemisphere experiencing a very mild flu season doesn't guarantee the United States the same. “We don't have a crystal ball and can't exactly predict what will happen,” says Koncilja. And given the fact that our country is still caught in the midst of COVID-19, even a modest flu season could still threaten to overwhelm our hospital system, he adds. In the 2019-20 flu season alone, the CDC estimates that between 410,000 and 740,000 people were hospitalized for flu, and 24,000 to 60,000 Americans died from the virus.
“Like COVID-19, older adults are particularly vulnerable to flu complications, given the fact that they have less robust immune systems and may have other underlying health conditions such as heart or lung disease,” Koncilja says. The burden on hospitals of the two simultaneous viruses is still a concern. A model from the Institute for Health Metrics and Evaluation at the University of Washington projects at least 200,000 more deaths from COVID-19 alone from the end of August to Jan. 1, 2021, with nearly30,000 ICU beds needed at its peak in mid-December.
How to stay safe
The most important thing every older adult needs to do is to get their flu vaccine, stresses Koncilja. (The CDC expects to have a record-setting 194 million to 198 million doses this year.) There are two specifically FDA-approved for older adults: Fluzone High-Dose, which has four times more antigen than the regular flu vaccine, and Fluad, which contains something called an adjuvant to promote a stronger immune response. Research has shown that both are more effective in older adults than the regular flu vaccine. During the 2018-19 flu season, the flu shot prevented an estimated 4.4 million cases of the flu, 58,000 hospitalizations and 3,500 deaths, according to the CDC.
While most adults get their flu shot at their doctor's office, if you're squeamish due to fears of COVID-19, Schaffner recommends calling your provider to let them know. Many offer special hours for older adults, and some will send a nurse outside to give you the shot in your car. “The risks of coming down with the flu are much greater than the risk of getting COVID in your doctor's office or pharmacy,” he explains. He recommends getting your shot in October, which gives your body at least two weeks to build up immunity before flu season gets underway.
The flu vaccine is designed to protect against the three, or more typically, four individual influenza viruses research indicates are most likely to spread and cause illness. But since it takes at least six months to mass produce the needed quantities, manufacturers often begin growing their vaccines as early as that January. As a result, sometimes the flu strains they choose don't match what ends up circulating around the public, explains Schaffner.
This year's shot provides protection against two A strains, H1N1 and H3N2, as well as two B strains, Victoria lineage and Yamagata lineage. About two-thirds of the flu samples WHO tested from the Southern Hemisphere have been influenza B, most from the B-Victoria lineage (included in our shot). The remaining third were influenza A, all the H1N1 strain (also included in the shot here). But keep in mind that the virus mutates every year, says Schaffner, which means that the flu you do get may not be an exact match for what's in the shot.
It's also important for older adults to double down on all the everyday preventive steps they've been taking to prevent the spread of COVID, adds Koncilja. This includes wearing masks whenever you're interacting with people outside of your household, practicing strict social distancing, and washing hands frequently with soap and water (and if that's not available, a hand sanitizer that contains at least 60 percent alcohol). Since symptoms of COVID and the flu can be interchangeable — they both often manifest with fever, chills, congestion, trouble breathing, and body aches — it's also important to reach out to your physician as soon as you begin experiencing symptoms, he adds. This way, you can get tested for both, and if you do have the flu you can take a prescription antiviral medication such as Tamiflu. “It may make a difference between being able to ride it out at home instead of going to a hospital,” says Koncilja.