Oh my. Right now, the dominant explanation for the surge in all sorts of viruses (along with some bacterial infections), especially among kids is a weak form of the immunity debt hypothesis: lack of previous exposure due COVID protections has created an immunologically naive population through which these diseases can spread. That is likely part of the story. But when I see data like this, I have some doubts:
If we focus on the lefthand figure, it’s pretty clear that last year, we had a ‘bad’ RSV season. Historically, 2021 seems par for the course, if not somewhat worse. In other words, COVID mitigation efforts didn’t limit the spread of RSV. At the same time, RSV hospitalizations are much higher than previous years among kids. It seems we’re seeing a higher rate of hospitalization per case of RSV in that age group.
Just to review:
- We had lots of RSV infections last year (2021).
- RSV infections in 2022 don’t seem to be abnormally high.
- Hospitalizations among kids for RSV are high.
These observations are not inconsistent with the notion of immunity theft: previous infections, such as COVID, can harm the immune system’s ability to respond to other infections–hopefully, not permanently (here’s a good explanation of immunity theft and the weak form of immunity debt). We need far more work to rule in or rule out immunity theft regarding COVID and RSV, and, of course, what applies to RSV might not apply to other diseases such as influenza. Given the potential harm beyond a COVID infection itself, the lack of a national effort to determine if COVID-related immunity theft is a problem (long- or short-term) is shameful.
Regardless of the mechanism, right now RSV and influenza are surging, pediatric units are slammed, and COVID appears to be rising in prevalence (again). Mask up and if you’re due for a COVID booster or a flu shot, get them.
I’m not sure it’s fair to say that COVID mitigation didn’t limit the spread of RSV. By the start of November 2021, COVID mitigation was, at that time, at its lowest point ever in my corner of the USA. Delta was done, Omicron wasn’t on the horizon and official discussions were underway about lifting the last few restrictions at the start of the 2022. It wasn’t until nearly January 1st 2022 that we did an abrupt about-face and reinstated mask mandates.
And this year: my hospital system waited nearly 3 weeks after the state declared an emergency due to RSV and the hospital implementing crisis standards of care…before writing a message to the public asking parents and caregivers “to think about masking in public spaces”. Yep, waited until every hospital is full in a 400 mile radius before asking the public to chip in. Apparently nobody learned anything in nearly 3 years of pandemic.
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