“We don’t really have great ways of predicting how bad the flu is going to be [each year],” says Deborah Lehman, MD, a professor of clinical pediatrics and an assistant dean for student affairs at the David Geffen School of Medicine at UCLA. “We’re always trying to catch up to the flu — but the flu is always ahead of us. The flu is smarter than we are, and we’re always trying to get ahead of it.” But monitoring flu activity can help you prepare for what’s in store. Every year, the CDC and the World Health Organization monitor the flu viruses that are circulating in the Southern Hemisphere and countries around the world to determine which might pose the highest risk. From there, a vaccine is created to help protect against the most commonly circulating viruses. “Tracking the flu helps us educate ourselves to perform better and better every year,” says Waleed Javaid, MD, the director of infection prevention and control at Mount Sinai in New York City. “What happens every few years is that we do have higher than normal cases of influenza,” says Dr. Javaid. “Though I think the biggest reason [for the 2017–2018 epidemic] is that not enough people were vaccinated.” Overall, the vaccine formulated for the 2018–2019 flu season offered a protection rate of 29 percent. It was initially much higher, at almost 50 percent effective in the beginning of the season. At that time, the dominant virus strain was H1N1, which the vaccine was formulated to protect against. However, toward the end of flu season, H3N2 emerged — and the vaccine was only 9 percent effective against that second strain of the virus. The 2019–2020 flu vaccine has been formulated to protect against both H1N1 and H3N2, as well as other strains that have been circulating. Though concerns about how effective the vaccine is — or isn’t — shouldn’t deter you from getting vaccinated. “The flu vaccine is not 100 percent effective,” says Dr. Lehman. But, she explains, if you and everyone around you gets vaccinated, even if the vaccine is only 20 to 30 percent effective, your community starts to develop what’s called a herd immunity, which helps keep everyone healthy — especially young children and the elderly, who are especially susceptible to the virus. If you suspect you may have the flu, it’s important to see your doctor for prompt diagnosis and treatment. Antiviral medications are available to help reduce symptoms, shorten the duration of the infection, and prevent complications — but are most effective when taken within two days of the onset of flu symptoms. “If you’re already three to four days in, they’re not going to be as effective,” says Lehman. “It’s better to try to avoid getting sick by getting the flu vaccine.”
