If past experience with wastewater monitoring is worth anything, we will see a surge in covid illnesses starting in the next few weeks. And, that may not be the only summer surge in the works.
Wastewater
CDC wastewater data for SARS-CoV-2 is very reminiscent of the last 2 summers when we saw subsequent upticks in covid illness.
Of course this can vary across the country and is less informative due to absence of wastewater tracking in large swatches of the country. Still, you can see that higher levels of activity (the darker the blue the more the virus concentrations, with gray denoting insufficient data) are common all over. (Data as of July 18, 2024.)
Contrast this with the latest map of influenza-like illness that should pick up covid cases - nothing much doing here.
Wastewater tracking methodology is the least changed post-pandemic, so it is the most useful information to use to compare with past years. Monitoring of infections, illnesses, hospitalizations, and deaths have all changed dramatically, due both to changes in individual behaviors in testing use and changes in reporting mandates for communities and medical institutions, with resulting under-reporting of clinical events due to covid. Keep an eye on what happens on the west coast, probably the first region to ring in the clinical surge.
Take-away point: it might be time for high-risk individuals to go back to masking and avoidance of high-density indoor crowds for a while. New covid vaccines may be available as early as next month.
Speaking of Influenza
Not surprisingly, more human cases of influenza A H5N1 have cropped up in Colorado, this time in poultry workers involved in culling infected chickens. Clinical illness is mild. CDC has sent an outbreak investigation team to these sites and, coupled with a serologic survey getting going in Michigan, should help define modes of transmission and range of clinical illness.
PEP Didn't Work for Covid
A new article in NEJM failed to show any benefit of nirmatrelvir-ritonavir (Paxlovid) compared to placebo in postexposure prophylaxis for household contacts of persons with covid infection.
It's a well-constructed study and should end talk about using this agent for post-exposure prophylaxis in most circumstances.
Fear of Flying
No, not the Erica Jong book. I came across a systematic review published recently suggesting that masking was beneficial on long airline flights. It covered studies performed in the early pandemic period so it may not be entirely reflective of current events, but it was interesting.
It's not overwhelming evidence, but wearing a mask on long airline flights might be a choice, both for high-risk individuals as well as for those who just don't want their expensive vacations spoiled.
Enterovirus Surge?
July through October usually is peak enterovirus season in the US, with much variability depending on climate and who knows what else. You may not be aware, but CDC has a National Enterovirus Surveillance System (NESS) set up to monitor enteroviral activity. It is a laboratory based system, and reporting is passive and voluntary, so it tends to have relatively little data and a significant lag in reporting spikes in enterovirus illness. 2023 data, as of April 2024, reported on 193 specimens tested at CDC for that entire year. It is mostly useful for identifying strains responsible for more severe illnesses such as acute flaccid myelitis.
Anecdotally though, it seems as if we're having one of those bumper years for enteroviral disease. In my telemedicine practice at a few regional hospitals surrounding Washington, DC, I've had a handful of newborns with mostly mild illness test positive. Similarly, I'm hearing a lot about hand, foot, and mouth disease from primary care doctors consulting me as part of some nationwide volunteer curbside consults I perform.
If this is true, primary care offices, urgent care settings, and emergency departments could get a little busy with covid and enterovirus illnesses soon.
