Tripledemic update, February 27, 2024.
This Data Snapshot looks like good news for the respiratory virus season. But let's not celebrate too soon.
Last week and yesterday, I saw a lot of viruses wreaking havoc in my two Boston ERs. Several cases of influenza (and, also, a couple of people with Covid-19) caught my attention. It had seemed to me (and the data confirmed this), that influenza had receded in February. Had something changed, I wondered?
I took a look at the Inside Medicine Covid-19 and Respiratory Virus Dashboard to see what the latest data have to say about Covid-19, influenza, and RSV hospitalizations in the US. Here are the national hospitalization rates for the three big viruses we track (Covid-19 in yellow, influenza in red, and RSV in blue):
As you can see, none of the three big viruses have suddenly surged, according to the data. Indeed, as of the week ending February 17th, things have really simmered down from the peak in late December/early January. Now, the public data we have always lag a bit, so I don’t yet know if what I saw in the ER the last week was just random chance/variance, or if my anecdotes are actually indicative of a surge that will show up on the dashboard over the next few weeks. (In addition, I wanted to see what I could find about my region. With respect to influenza and RSV, the nearest state I can look at using CDC data is Connecticut—and things didn’t look bad there either, as of February 17th, anyway.)
We won’t know until the data for last week are released this Friday. Nevertheless, I wanted to share my frontline perspective, especially since a few other colleagues I asked about this said they’d noticed the same thing. Time will tell if the data confirm or refute our experience. (It’s also possible that I happen to practice in a pocket with a real outbreak, but which might not show up in regional or national data.)
Don’t dance in the end zone yet. Late February and March surges can be a thing.
While the data do not yet show it, it would not be shocking if any of these viruses made a stand in late February and early March. That often happens, especially with influenza.
Cool research alert: In fact, when Covid first arrived on US soil in significant numbers in late February and early March of 2020, many clinicians thought they were seeing a late rush of influenza. What were many of them really seeing, hiding in plain sight? An undetected influx of milder Covid-19 cases that we could not yet diagnose. Recall that we could not test for Covid routinely yet back then. In addition, clinicians often prescribe medications for influenza without testing for it (or before test results are back). That insight actually helped a team of clever researchers here at Harvard reach a far better estimate for how many Covid-19 cases there really were early in the US outbreak. No surprise, there were likely many more Covid-19 cases in late February and early March of 2020 than reported (owing to lack of tests, and the strict testing requirements at the time). That, in turn, gave me a chance to estimate what turned out to be a rather accurate case fatality rate; my estimate ended up being right in line with what later and far more careful research (led by my friend, the Aussie epidemiologist and wonderful writer Dr. Gideon Meyerowitz-Katz) would go on to conclude—and both of our estimates were certainly far better than the (eye-popping but inaccurate) early figures that the WHO publicized early in the pandemic.
All of this is to say, late February and March are not the end of the respiratory virus season, by any means. So please take the precautions you need and keep an eye on the data. (I’ll keep you updated if and when anything changes.)
In the meantime, if you want to explore your state or county, here’s the link to the Inside Medicine Dashboard covering Covid-19, influenza, and RSV. Just keep in mind that these data reflect how things over a week ago.
And if you want to support all of the work that we bring you, here’s the handy upgrade link. Or, click the…
Thanks as always to Benjy Renton for maintaining the Inside Medicine Dashboard.
As a teacher in Houston, Texas we are still seeing flu, Covid, and all the “unknown snot causes”. Hoping the rodeo and spring break don’t help us go up!
I would caution against becoming "the boy who cried wolf" where even during good health stretches the message is "Be vigilant. It may look clear but I wouldn't be so confident. And even if it is clear now what about next month?" It is what has happened with the economy the past 8 months where we are clearly in a good place yet negativity is the rule. At some point people tune you out (I believe this happened, unfortunately, with most of the country on Covid 2 years back already).