I actually had to pull out the lawnmower this week, to cut some weedy grass running amok in the yard. Nonetheless, I'm buoyed by the approach of the vernal equinox next Tuesday, the official start of spring. Winter will be done, and with it the winter respiratory viruses. They will reliably be replaced with spring respiratory viruses.
Here's a look at the pediatric infectious disease news the past week.
Details on the Failed GSK RSV Vaccine Trial
We've known for about a year that GlaxoSmithKline's RSV vaccine trial in pregnant people was stopped due to safety concerns: a higher rate of preterm births in the vaccine group compared to placebo. Now we have more details, similar to what was reported to FDA and shared in various meetings. Preterm birth rate was 6.8% (237 of 3494 infants) in the vaccine group and 4.9% (86/1739) in the placebo group; it was statistically significant. Neonatal mortality was higher in the vaccine group, 0.4% versus 0.2%, but did not reach statistical significance.
On the other hand, vaccine effectiveness was pretty good:
The currently approved maternal RSV vaccine from Pfizer also had a hint of a safety signal for preterm birth, less so than the GSK product, and these signals combined resulted in the Pfizer vaccine being approved for a later time in gestation, at 32 weeks at the earliest. Postmarketing surveillance is ongoing. Perhaps the most difficult part of assessing this safety signal is whether it is real or not. We are lacking a key factor in making this assessment: biologic plausibility, i.e. the mechanism by which these vaccines might cause preterm birth. Without that, it is still possible this represents just a chance observation. From my perspective, I would still encourage RSV vaccination for pregnant people as well as nirsevimab therapy for at risk infants born to unvaccinated mothers. We have time for more discussions of any new data prior to our next RSV season this fall.
Waterborne Disease Outbreaks Associated With Drinking Water
I'm a big fan of CDC's Surveillance summaries, and this one published last week is of interest. The report concerns 214 outbreaks from 2015-2020. I wasn't thrilled to see my home state represented prominently.
Outbreaks occurred year-round, and biofilm exposures predominated.
In case you aren't familiar with biofilm-associated outbreaks, here's the quick explanation from the text:
"...microbial communities that attach to moist surfaces (e.g., water pipes) and provide protection and nutrients for many different types of pathogens, including Legionella and NTM [non-tuberculous mycobacteria]... Biofilm can grow when water becomes stagnant or disinfectant residuals are depleted, resulting in pathogen growth... Furthermore, biofilm pathogens are difficult to control because of their resistance to water treatment processes (e.g., disinfection)... Exposure to biofilm pathogens can occur through contact with, ingestion of, or aerosol inhalation of contaminated water from different fixtures (e.g., showerheads) and devices (e.g., humidifiers)..."
Not to minimize the severity of these events, but I couldn't help thinking about a whole new version of Hitchcock's Psycho shower scene based on this.
Legionella was by far the most common pathogen. The report has detail on every outbreak by year and location, as well as a listing of contributing factors. It's a great roadmap for future prevention.
Measles (Again)
It seems like I could devote every week's post entirely to measles and not run out of things to say. Here's the current US situation.
As I've stated previously, it's the sheer number of unconnected sites that concerns me now. Let's put this into some perspective.
As of March 14, we have 58 cases reported from 17 jurisdictions. In all of 2023, we had the same number, 58, reported from 20 jurisdictions in the US. So, we're way ahead of the game for recent years, but we're also not breaking any records compared to pre-pandemic times.
Looking more closely at the 2 biggest years recently, the 2014 (and somewhat 2015) numbers had a large contribution from a single site, Disneyland. More impressively, the 1274 measles cases in 2019, the highest number in the US since 1992, largely involved orthodox Jewish communities in New York - relatively epidemiologically isolated communities with very low immunization rates. A CDC update in fall 2019 (I couldn't find a final tally) stated that 75% of cases for the entire country that year originated from these communities.
Fingers crossed that we don't eclipse the 2019 figures this year, but with reduced vaccination rates and already widespread measles transmission occurring, it doesn't look good. We're just now coming to the spring break and summer travel season - importation of measles from travelers has been a large contributor to US measles outbreaks in the past.
Pediatric Covid ICU Admissions
A recent report of registry data from 55 hospitals during the first almost 2 years of the pandemic showed that about 8% children <21 years of age admitted to intensive care with covid had immunocompromising conditions (ICC). Secondary bacterial infection was more common (9.5% versus 7.3%) and mortality (11.4% versus 4.6%) was higher in the ICC group.
That Pesky Flu
The map is getting a little greener, apropos of springtime. Note in the link you can animate the map to show progression from the fall to the current week.
Better seen here, we did experience a little pause in our decrease of ILI, now headed down but at 3.7% still above the official "epidemic is over" mark of 2.9% for this year.
Any Chipmunk Sightings?
My 2024 Farmer's Almanac says that the real harbinger of spring in the eastern US is the appearance of the eastern chipmunk (Tamias striatus) above ground. As opposed to their squirrel brethren, chipmunks at my house don't bother my bird feeder, so I'm OK with them. I learned that although they stay below ground for the winter, they aren't true hibernators but rather experience torpor. They may sleep for several days in their bedrooms, followed by a trip to the underground pantry for snacks. Sounds like a good plan for retirement.