Cate Roser

While COVID-19 and other respiratory illnesses are still spreading on Yale’s campus, some experts believe that the country has seen the worst of the 2023-24 “tripledemic.” 

“Tripledemic” refers to the three illnesses — respiratory syncytial virus, or RSV; the flu; and COVID-19 — that spike every winter and fall.

Scott Roberts, an infectious diseases specialist and associate medical director at the School of Medicine, said he believes multiple indicators show that levels of all three respiratory illnesses have already peaked in Connecticut.

“Caseloads across the state, wastewater data and current hospitalizations are now showing slight decreases in all three viruses,” Roberts wrote in an email to the News. “I always take these [post-holiday break] weeks with a grain of salt because often there is decreased testing due to the holidays, but regardless, I am enthusiastic the downward trend will continue.” 

Roberts said he doesn’t believe we will see a resurgence of COVID-19 this season since there is “no new concerning variant on the horizon.” However, he suspects that there could be a second wave of flu infections due to the influenza B viral variant, which frequently circulates later in the season. 

According to Madeline Wilson, an assistant professor at the School of Medicine and the chief campus health officer at Yale, there is currently an increase in respiratory virus activity among students on campus due to classes resuming and students returning to campus after the holiday break. Still, given the national and local outlook, she does not expect this trend to last for long. 

“We fully expect cases on campus to wane over the next several weeks,” Wilson wrote in an email to the News.

According to Roberts, the 2023-24 flu season looks very similar to last year’s, although cases this year seem to be peaking later, around New Year’s instead of early December. 

Further, this year’s and last year’s flu seasons remain much worse than the 2020-21 and 2021-22 flu seasons, likely due to the loosening of COVID-19 restrictions since then.

“[W]e saw this last year especially,” Roberts said. “Since no one encountered flu for a prolonged period, there was likely waning immunity that resulted in a more severe flu season than usual since so many people were newly seeing flu again and had lost some of their baseline immunity.” 

Roberts noted that while the COVID-19 pandemic may have increased the severity of the past two flu seasons, it may have also brought about some positive changes to flu season. The pre-COVID-19 pandemic 2019-20 flu season was comparable to the 2022-23 flu season due to very high levels of influenza B variant in 2019. However, during the COVID-19 pandemic, the Yamagata strain of influenza B has become extinct, which Roberts said is “remarkable.” Today, this strain is no longer included in flu vaccinations.

According to Thomas Murray, a pediatric infectious diseases physician and associate medical director at the School of Medicine, flu season has returned to pre-pandemic patterns, even with the introduction of COVID-19. Nevertheless, he notes that it is important to test for COVID-19 if you have symptoms.

“It is very difficult to tell the difference clinically between these different viruses,” Murray wrote in an email to the News. “To help contain spread if you have signs and symptoms of respiratory disease I would recommend a COVID-19 test and possibly an influenza test, as both can spread easily in populations that spend a lot of time together in congregate indoor settings.”

Roberts also recommended that students implement the “tried and true” strategies for preventing illness and its spread to others, such as hand washing, good ventilation, masking in high-risk settings, staying home when they are sick and keeping up with vaccinations. He encouraged students to remain up to date on CDC guidelines for vaccination since there have been several changes this year, including a new RSV vaccine and an updated COVID-19 vaccine. 

Flu and COVID-19 shots can be scheduled online for free for all Yale Health members, Yale University employees and Yale University students.