After weeks of skyrocketing cases, the tripledemic of COVID-19, RSV, and influenza appears to be slowing down across parts of the United States. However, the CDC warns that flu activity is still high and COVID cases remain above last year’s rates. Several factors have contributed to the recent decline, but experts say it is too early to declare victory as new Omicron subvariants are spreading quickly.
The latest data from the CDC shows encouraging signs that the tripledemic surge may be easing across parts of the country. After peaking around the new year, cases of flu and RSV have fallen for two weeks straight while new COVID hospitalizations are showing signs of plateauing.
This comes as a relief for many hospitals that were overwhelmed by the triple threat of respiratory illnesses over the holidays. At one point in early January, nearly 80% of beds were full at some children’s hospitals while adult ICUs faced similar strains.
While the situation may be improving, CDC data shows that flu activity is still high across most of the U.S. Likewise, COVID cases remain significantly above last year and RSV continues to circulate at elevated levels.
|Change from Peak
So while declines are welcome news, experts caution that it’s too early to declare the end of the tripledemic as all three viruses continue spreading through communities.
Several factors appear to be driving the recent drops in cases. Colder weather kept more people indoors throughout December, facilitating easier spread. More indoor holiday gatherings also enabled widespread transmission.
With students out of school for winter break and many adults working remotely or taking time off, cases have fallen with less contact between people. Experts speculate that rising immunity from vaccination and previous infection may also be slowing down the viruses to an extent.
However, CDC models predict another 150,000-200,000 flu hospitalizations before the end of flu season in May. So while cases may continue trending downwards, the viruses still pose significant threats, especially to high-risk groups.
While cases of original strains may be declining, experts are warily watching several new Omicron subvariants that are spreading rapidly. The XBB.1.5 variant, known as Kraken, now accounts for over 70% of U.S. COVID cases. The BF.7 strain dubbed Centaurus makes up another 20%.
So far, real-world data suggests these new variants largely evade immunity whether from vaccination or previous infection. Fortunately, they do not appear to cause more severe disease. However, their increased transmissibility facilitates further spread which could spark another surge.
Likewise, influenza evolution enables new strains to bypass existing immunity over time. Already, CDC genomic sequencing shows that this year’s dominant A(H3N2) strain differs from last year’s vaccine formulation. Continued viral evolution poses an annual threat requiring updated vaccines.
While RSV does not mutate as readily, its wide pediatric spread means much of the population lacks prior immunity. As children return to school, circulation will likely increase facilitating further transmission.
For now, cases of all three viruses appear to be declining from their early January peak. However, as past pandemic waves have shown, progress can quickly reverse as viral evolution and waning immunity enable comebacks. With new variants already comprising over 90% of cases, experts remain cautious.
|Share of Cases
| XBB.1.5 (Kraken) | 72% | Rapid spread from mutations evading immunity
| BF.7 (Centaurus) | 18% | Also spreading quickly with immune evasion
Most expect cases to begin increasing again as schools reopen, facilitating renewed spread among children. This annual pattern brought summertime waves during previous pandemic years and will likely enable continued circulation at some level.
The key variables will be how quickly and how far case counts rise as warmer weather approaches. With such high levels of infection in recent months, there are concerns that viral evolution may birth even more troublesome variants in coming weeks. Continued genomic surveillance will remain vital for staying ahead of emerging threats.
In the meantime, the public health playbook remains the same. Vaccination, boosters, masking, improved ventilation, social distancing, and testing can help curb transmission across all three viruses to limit caseloads. While positive signs have emerged, it remains as important as ever to keep guard up against the lingering tripledemic.
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