Why fears over a ‘tripledemic’ are surging

Cases of three major respiratory viruses — the flu, COVID-19 and RSV — are surging in the U.S., pushing the country toward a feared “tripledemic” during its first post-pandemic respiratory viral season. 

Optimism was high this autumn as the U.S. headed into the viral season. The national arsenal against these viruses had vaccines against RSV for the first time, newly updated COVID-19 vaccines, and the flu “immunity debt” that plagued children in 2022 was history.

But now, confidence is waning. Accessing the vaccine for RSV, or respiratory syncytial virus, has been a struggle for many, and enthusiasm for the new COVID-19 vaccines turned out to be abysmal. COVID-19 hospital admissions have been rising since November and wastewater detection indicates most sites — 69 percent — are seeing large increases in virus levels. 

Flu activity across the country is currently “elevated and continues to increase in most parts of the country,” according to the latest update from the Centers for Disease Control and Prevention (CDC). And vaccine uptake for the flu seems to be lagging, with the CDC saying nearly 8 million fewer people got the shot by mid-December compared to the same period in 2022. 

During the first couple of years of the pandemic, flu activity remained low, attributed to the precautionary measures that communities took to mitigate the viral spread of COVID. The 2022-23 flu season appeared to mark a return to normal flu levels.

Only about a fifth of U.S. adults say they’ve received the newest COVID-19 shot, according to polling from KFF. Uptake for the previous bivalent shots was similarly low and many Americans likely haven’t been immunized since receiving their first doses in 2020 or 2021. 

“We’re definitely seeing an increase in the number of flu cases, COVID-19. They’re both surging right now,” said Luis Ostrosky, chief of infectious diseases and epidemiology with UTHealth Houston and Memorial Hermann. 

Speaking on the RSV cases he’s seen in the Houston area, Ostrosky said infections appeared to surge earlier in December, though he is still seeing a “steady” number. 

“This is so alarming that it prompted CDC to send out a health alert towards the end of December reminding all clinicians to really work on getting patients vaccinated and, when they have symptoms, tested so that they can access therapy if they need it,” Ostrosky noted. 

Available RSV data from the CDC does seem to suggest test positivity peaked toward the end of November, with the positivity rates for antigen and PCR tests just beginning to drop in recent weeks. 

Hopes were high that the approval of two RSV vaccines for seniors and a preventive monoclonal antibody for infants would help keep cases low this season. 

But Sanofi, the maker of the monoclonal antibody Beyfortus, said in October that “unprecedented demand” had led to short supply, leading the CDC to advise doctors to reserve doses for their highest-risk patients. 

And RSV vaccine uptake among seniors appears rather lackluster, with CDC data suggesting only about 10 percent of nursing home residents had gotten immunized against the virus by mid-December. 

“The numbers are not looking good,” said Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials, of the three circulating viruses. 

“I think when we get some new numbers for the last week, it’s going to be sort of continued trends in the same direction and increased activity across all of those conditions,” added Plescia. 

A holiday “bump” in cases is to be expected following weeks of year-end travel. AAA estimated in December that more than 115 million people in the U.S. would be traveling 50 miles or more from home during the festivities. 

Amid all the travel, Plescia lamented that social norms which he hoped became commonplace following the pandemic appeared to have been largely abandoned. 

“I think we’re kind of going back to, you know, the old approach of people don’t stay home when they’re sick,” said Plescia. “And they think it’s sort of a minor thing and the thought that they might infect somebody else just doesn’t really occur to them.” 

Masking has also become rare once again, though Plescia noted many hospital systems are bringing back mask requirements amid the rise in respiratory viruses. These hospital-enacted requirements may be more easily accepted by communities than those issued by the government, and Plescia expects to see more like them in the future. 

While cases are rising, Plescia said his organization hasn’t yet heard of any health systems around the country being unduly stressed by the respiratory viral situation. 

“That is sort of the first concern with some kind of ‘tripledemic’ is that we would have so many people getting sick that hospitals would become overwhelmed either because they didn’t have enough beds or they didn’t have enough staff to care for that number of people. We’re not hearing that we’re approaching that, but that is the thing that we’re most concerned about,” he said.

Ostrosky is optimistic case rates will begin to go down soon after a potential holiday bump, with past winter peaks indicating a drop sometime in early January. He emphasized it is still worthwhile to get tested if you experience symptoms because there is now a plethora of therapeutics available for treating these infections. 

Going forward, Plescia also recommended that more focus be placed on vaccinations among health care workers. 

“That’s important not just because we don’t want health care workers to get sick and give it to their patients but also, you know, when you have a lot of health care workers getting sick, this whole capacity thing becomes problematic,” Plescia said.

“Because what we’re hearing now is that hospitals are less concerned about not having enough beds. They’re more concerned about having enough health care workers to staff those beds.”