Cameron Wolfe, MBBS
Cameron Wolfe, MBBS, associate professor of medicine, division of infectious disease, Duke University Medical Center.
For the past few years, influenza has taken a backseat to COVID. It’s not just that people weren’t paying attention, either: There were fewer cases of flu even though testing and reporting were up. The most likely explanation is that COVID prevention measures, like masking, handwashing, and social distancing, kept us safe from more than one virus.
But now that people have largely returned to prepandemic habits, the flu could become a problem once again. Even though last winter was a “light” flu season, there were still up to 170,000 hospitalizations and 14,000 deaths, according to estimates from the U.S. Centers for Disease Control and Prevention. Here are some simple steps to stay well this winter.
One of the silver linings of the COVID-19 pandemic is the normalization of people staying home when they’re sick. It’s no longer a badge of honor to drag your coughing, sneezing, and GI-disturbed self to work, now that people are more aware of just how risky it can be to share air with the sick.
In fact, you don’t even have to cough and sneeze to spread germs. Researchers from the University of Maryland reported that people can spread the flu simply by breathing. Donald Milton, MD, MPH, examined the exhaled breath from 142 people with influenza when they were breathing, speaking, coughing, and sneezing on the first three days they experienced flu symptoms. His team found that flu patients routinely shed infectious virus into aerosol particles small enough to present a risk for airborne transmission. Neither coughing nor sneezing appeared to contribute significantly to influenza virus shedding.
Since it’s not practical to stay home all winter to try to avoid contracting the flu, the next best thing is to protect yourself as much as possible. Although it’s only about 10 to 50 percent effective, the flu vaccine is still highly recommended as part of your prevention strategy. The vaccine’s effectiveness depends on how well each year’s formulation aligns with the prevalent strain of the year. (To have vaccines ready each year, scientists predict which strain will be active before flu season hits, and they don’t always get it right.) For the 2022-2023 season, the flu vaccine is based on the strain that predominated last year (3C.2a1b.2a.2).
The flu shot contains a dead virus and can’t give you the flu. You may, however, feel a little run-down after getting the shot. As your body produces protective antibodies, you may have muscle aches or a fever for a day or two. It takes two weeks for the shot to provide full protection.
You’ve probably met someone who skips his or her yearly flu shot and still doesn’t get sick. Researchers from the University of Michigan and Duke University who wanted to understand this phenomenon infected 17 people with the flu virus and made an interesting discovery. The people who stayed well weren’t immune to the flu—in fact, they had a significant immune response to it—they just experienced it differently and with no symptoms. The researchers found that those people had differences in their biological metabolism and gene expression, explained study author Alfred Hero, MD, in PLoS Genetics. And those differences, he noted, “had to do with antioxidants.”
That specific study did not explore the effects of eating an antioxidant-rich diet, but several others have, and one particular compound stands out: quercetin, a flavonoid found in tea, chocolate, and red wine. In 2021, researchers reported in the journal Biomolecules that quercetin indirectly inhibits the influenza A virus, regulates the inflammatory response, and lessens the severity of illness.
While flavonoids have been found to have a variety of potential health effects, a study published in Science suggests that they may work best to limit the damage caused by flu in the presence of a specific intestinal microbe: Clostridium orbiscindens.
“It’s not only having a diet rich in flavonoids; our results show you also need the right microbes in the intestine to use those flavonoids to control the immune response,” the study’s senior author, Thaddeus Stappenbeck, MD, PhD, explained. While this is early animal study information, the authors noted that it certainly can’t hurt to boost your intake of flavonoids. The researchers are now investigating ways to boost the gut health of people who don’t have enough C. orbiscindens.
It’s important to follow the CDC recommendations to wash your hands frequently, avoid touching your face, and keep surfaces clean and disinfected, but those steps may not be enough to avoid getting the flu. For added protection, get an annual flu shot and eat plenty of antioxidant-rich foods. If you get sick, help protect others by staying home until your fever has subsided without medication for 24 hours.
