Last year’s “triple-demic” marked the beginning of what may be a new normal: a confluence of respiratory infections — RSV, influenza, and covid-19 — will surge as the weather cools each year.
Like blizzards, the specific timing and severity of these outbreaks are hard to forecast. But their damage can be limited in more ways than ever before. More protective vaccines against influenza are on the horizon. And new vaccines against respiratory syncytial virus, or RSV, were approved this year, as were updated covid vaccines. Although the first days of rollout for the Moderna and Pfizer vaccines saw hiccups, with short supplies at some pharmacies and billing confusion with some insurers, the shots now are generally available at no cost.
What’s more, after enduring the worst pandemic in a century, people are more attuned to protecting themselves and those around them. Wearing face masks and staying home when sick can stop the spread of most respiratory infections. The rate of flu vaccinations has climbed over the past five years.
“It seems like the pandemic reminded them of how important vaccination is,” said Brian Poole, a microbiologist at Brigham Young University in Utah. In a study of college students, Poole and other researchers found that flu vaccination rates have nearly tripled since 2007, from 12% to 31% in the respiratory infection season of 2022-23. Only a minority of students expressed “vaccine fatigue.”
There is, however, one dangerous departure from the past. Vaccination has become politicized, with college students and older adults who identify as Republican or conservative being less likely to get covid vaccines, as well as vaccinations against flu. Before 2018, studies found that political affiliation had no influence on vaccine uptake. But as measures to limit covid, such as school and church closures, became controversial, some political leaders downplayed the effects of covid — even as the pandemic’s U.S. death toll soared above 1 million.
That messaging has led to a disbelief in public health information. The Centers for Disease Control and Prevention reports data showing that covid hospitalizations nearly tripled in the latest surge, with more than 40,000 hospitalizations in the first two weeks of September compared with about 13,600 in the same period of July. But in a recent KFF poll, half of Republicans did not believe in the surge, compared with just 23% of Democrats.
Messaging to minimize the toll of covid also makes vaccines seem unnecessary, with 24% of Republicans leaning toward getting the updated covid shot versus 70% of Democrats in the KFF poll. A larger share of vaccine-eligible adults said they planned to get, or have gotten, the flu shot and a new RSV vaccine.
“It’s important to recognize that the flu, covid, and respiratory viruses still kill a lot of people, and that the vaccines against those viruses save lives,” said David Dowdy, an epidemiologist at Johns Hopkins University in Baltimore. Flu vaccines prevent up to 87,000 hospitalizations and 10,000 deaths each year in the United States. “I like to highlight that,” Dowdy added, “as opposed to making up terms like ‘triple-demic’ to make people cower in fear.”
Dowdy predicted this fall and winter will be better than the past few, when patients with covid, influenza, or RSV filled hospitals. Even so, he estimated that more people will die than in the seasons before covid appeared. About 58,000 people died from the flu last season, and hundreds of thousands more were sickened, staying home from school and work. This year, the flu doesn’t appear to be kicking off unusually early, as it did last year with cases picking up in November, rather than in January. And more people are partially immune to covid due to vaccines and prior infections.
The effectiveness of flu vaccines varies depending on how well its formula matches the virus circulating. This year’s vaccine appears more protective than last year’s, which reduced the risk of hospitalization from the flu by about 44% among adults. This year, researchers expect an effectiveness of about 52%, based on data collected during South America’s earlier flu season. Its benefit was higher for children, reducing hospitalizations by 70%.
The flu’s toll tends to be uneven among demographic groups. Over the past decade, hospitalization rates due to the flu were 1.8 times as high among Black people in the United States as among white individuals. Just 42% of Black adults were vaccinated against the flu during that period, compared with 54% of white or Asian adults. Other issues, ranging from a lack of paid sick leave and medical care to a prevalence of underlying conditions, probably contribute to this disparity. People who have asthma, diabetes, or cardiovascular issues or are immunocompromised are at higher risk of a severe case of flu.
Sean O’Leary, an infectious disease pediatrician and the chair of the American Academy of Pediatrics committee on infectious diseases, urges parents to vaccinate their kids against influenza and covid. Children hospitalized with co-infections of the two viruses last year were put on ventilators — an intense form of life support to allow them to breathe — far more often than those hospitalized for the flu alone. And covid is surging now, O’Leary said. Hospitalizations among children under age 18 increased nearly fivefold from June to September. “Almost all of our kids who have died have been completely unvaccinated” against covid, he said.
The FDA greenlighted new RSV vaccines from the pharmaceutical companies GSK and Pfizer this year. On Sept. 22, the CDC recommended that pregnant mothers get vaccinated to protect their newborns from RSV, as well as infants under 8 months old. The disease is the leading cause of hospitalization for infants in the United States. The agency also advises people age 60 and older to get the vaccine because RSV kills between 6,000 to 10,000 older adults each year.
Rather than vaccination, the CDC advised a new long-acting antibody treatment, nirsevimab, for children between 8 to 19 months old who are at risk of RSV. However, the price could be cost-prohibitive — anticipated at $300 to $500 a dose — and many hospitals lack the staff needed to administer it. Although insurers cover it, the American Academy of Pediatrics warns that reimbursement often lags for a year. “We don’t have the infrastructure in place to ensure all children can access the product,” said its president, Sandy Chung, in a statement. “And that is alarming.”
If the wrinkles can be ironed out, said Helen Chu, an infectious disease specialist at the University of Washington in Seattle, better tools could arrive as early as next year. Pfizer, Moderna, and other pharmaceutical companies are developing mRNA vaccines against influenza and RSV that may more precisely target each year’s circulating virus.
Today’s flu and RSV vaccines are produced using traditional vaccine platforms, such as within chicken eggs, that are more cumbersome to handle, and therefore the vaccines take longer to develop each year. And President Joe Biden has awarded companies $1 billion to develop covid vaccines that provide longer protection.
“The future is going to be all three vaccines together,” Chu said, “but that will be a while yet.”