If cold and flu season seems to be hitting your household harder this year, you’re not alone. This is the year when common viruses that took a backseat to Covid-19 finally return.
Positive tests for the flu in the United States stood at 25 percent in late November, according to the US Centers for Disease Control and Prevention, compared to 8 percent at the same time of year in 2019. Respiratory syncytial virus (RSV) has pushed some children’s hospitals to capacity. And Covid hospitalizations are rising again. It’s the tripledemic that epidemiologists feared—those viruses, with the help of a few other seasonal recurring ones, are working together to fuel weeks of coughing, runny noses, and fevers. So if your kids, your coworkers, and everyone you know has been feeling sick, that’s why.
“This season is truly unprecedented,” says Katelyn Jetelina, who writes Your Local Epidemiologist, a newsletter about infectious disease spread. The high rates of flu-like illness could be an early peak, or an early warning of a monumentally bad season. “How high it will go, and how severe it will be, is unfortunately something we have to wait and see,” she says. “We’re at the mercy of time.”
The problem goes beyond making everyone feel sluggish and icky. CDC director Rochelle Walensky has confirmed that the flu, RSV, and Covid are putting stress on US hospital systems. It’s the unintended consequence of measures that sought to save lives—social distancing and mask-wearing curbed the spread of flu and RSV in 2020 and 2021. (Although there was a warning sign in 2021, when RSV cases in the US had an out-of-season uptick over the summer, an indicator that things were shifting in the wake of Covid.) Now these viruses are roaring back, and hitting a burned-out health care system that’s spent three years treating Covid infections.
These viruses are sweeping through young children who have no prior exposure to them and no immunity. Older people and the immunocompromised are at higher risk too. Experts aren’t recommending dropping all guards to build immunity. But they do note that social distancing and masking measures played a role in throwing other viruses off their historical patterns. “By doing that, you prevent all these other things that are less infectious typically,” says Mary Krauland, a research assistant professor in the School of Public Health at the University of Pittsburgh. “Over time, people are a little more susceptible.”
RSV typically causes mild illness, but it can prove particularly dangerous to young children whose small lungs cannot cough forcefully enough to clear mucus. Nearly all children contract the virus before the age of 2. But more kids are getting sick at the same time now, and pediatric hospitals have been overwhelmed in recent weeks by the sudden surge. In the United States, hospitalizations for kids 4 and younger spiked to 61 per 100,000 in mid-November, according to data from the CDC. That rate peaked at 26 young children per 100,000 in the 2019 to 2020 RSV season. And some hospitals are now short on pediatric beds. Because Covid largely spared children from severe illness, some hospitals pivoted, opening spaces designated for kids up to adults. Some of those beds never went back.
Eric Biondi, director of the Pediatric Hospital Medicine Division at Johns Hopkins Children’s Center in Maryland, says the beds there are full. The center even opened surge beds, but those are now full too. The children’s hospital is no stranger to fielding severe illness from RSV and the flu, but this year they’ve hit simultaneously.
“It’s been rough,” Biondi says. “The [RSV] spike happened quick. There was no flattening of the curve. It just went up.” Now, those cases have fallen off; RSV hospitalizations in the US steeply declined by the end of November to about 18 young children per 100,000, but that number is still high for November and December, compared to prior years.
But the flu continues to circulate. This year, the flu has already caused 78,000 hospitalizations and killed 4,500 people, the CDC estimates. It killed an estimated 25,000 people in the US during the winter 2019 to spring 2020 flu season. “Minimal flu activity” left the CDC without estimates in the winter of 2020 and spring of 2021, but the agency noted that less than 1 person for every 100,000 was hospitalized with influenza, compared to 66 people per 100,000 the prior year.
The threats are seen in Europe too, where the World Health Organization notes that flu season also got an early start. England is also seeing more than a quarter of influenza tests come back positive, and RSV hospitalization rates there are on the rise. German hospitals are strained with RSV infections. But babies in countries without robust medical systems are most at risk.
Once center stage, Covid is still circulating around the globe, although many people may have dropped their guard as schools went back and now the holiday season has begun. During the last week of November, hospitalizations for Covid-19 in the US averaged 4,200 each day—a 17 percent increase from the prior week, according to the CDC. Across Europe, Covid-19 cases saw a slight drop of 3.5 percent in late November.
Low vaccination rates compound the issue. By mid-November, just 40 percent of kids in the US had received a flu shot, according to the CDC. Only 12 percent of people ages 5 and older in the US have received updated booster shots targeting the Omicron Covid variant. Just under 15 percent of people in Canada have received a Covid booster since August. There is no RSV vaccine, although Pfizer is working on one and plans to submit it for approval to the US Food and Drug Administration before the end of the year. GSK has also submitted an RSV vaccine for older adults for review to regulators in Europe and the US.
Even though some hospitals are under stress, widespread closures of businesses and schools seem unlikely. Lockdowns spare medical systems from being overwhelmed, but they can lead to losses in educational attainment and income, and negatively affect mental health. But letting winter viruses circulate has its own economic costs.
“We know that illness lowers productivity,” says Nicholas Papageorge, an associate professor of economics at Johns Hopkins University. A study examining the economic costs of the flu in 2015 found that it led to $8 billion in indirect costs related to missing work in the US. “We know that these illnesses are costly and can be really dangerous, but we also know there are trade-offs,” he says. “If we’re extra cautious about health, it means we’re incurring costs elsewhere.”
Now that there are fewer masking and distancing requirements, virus mitigation efforts fall largely on individuals. Wearing a mask, isolating, testing for Covid, and avoiding large crowds still help people avoid getting sick—and are especially important for those who are vulnerable to severe illness. (In the US, the CDC is encouraging people to begin wearing masks again.) And keeping babies from contracting RSV until they are older can help them better fight it off.
Still when individual mitigation efforts are taken by many, they can have a collective effect. “Infectious diseases violate the assumption of independence,” says Jetelina. “What you do affects those around you. I really wish we approached not just Covid-19, but all these respiratory viruses, as a team effort.”
