This month always bring me back to The Happenings version of "See You in September;" I remember it fondly from my junior high school era. The Harvest Month often is a transition period from summer to fall/winter infections.
The Respiratory Infection Front
Right on schedule, the ACIP published its official flu vaccine recommendations. Nothing new in there, but it's a good one-stop shopping place for seasonal flu information. Things remain calm on the overall respiratory illness view, and covid may have reached its peak.
However, I'm still waiting for covid wastewater trends to start heading down in most areas of the country (same link as above). We may not be out of the woods yet.
Also note that the covid vaccine from Novavax was authorized by FDA this week. I'll be interested to see how effectiveness compares to that of the mRNA vaccines; Novavax targets a slightly earlier variant (JN.1) than the Pfizer and Moderna products which used KP.2. KP.2 is decreasing in prevalence in the US but still is more closely related to the current variants KP.3.1.1, KP.2.3, KP.3, and LB.1.
We have more longterm follow-up information about myocarditis and covid, looking at both vaccine- and natural infection-associated complications compared to other ("conventional") etiologies. It looked specifically at individuals 12-49 years of age hospitalized with myocarditis. Without going into great detail, it was clear that vaccine-associated complications were less common than with myocarditis associated with conventional or SARS-CoV-2 infection; however, confidence intervals were wide for several of the outcomes due to low numbers of events.
I was excited to see a new update from the HIVE (Household Influenza Vaccine Evaluation) program that has been monitoring households in Michigan since 2010 and was expanded to cover other respiratory infections in later years. The new update covers the years 2015-2022. (The watermark in the figures below signifies this is an accepted manuscript that hasn't yet appeared in the print journal.) Even though it's limited to southeast Michigan, it is valuable data because it is an ongoing active surveillance program in these volunteer households and gives us a glimpse of how the pandemic affected other virus epidemiology.
Far Away Challenges
Mpox continues to rage in the DRC and other areas of Africa, with exported cases appearing in far-flung countries. In addition to vaccine, these countries need better front line diagnostic tests. WHO has requested test manufacturers to apply for emergency approval.
On the polio front in Gaza, we've all heard the good news that there will be a pause in fighting to allow for vaccine administration, but it remains to be seen if this will really happen. Regardless, this will be an extremely difficult undertaking, targeting over 600,000 unprotected children in the region.
Bugs Transmitting Bugs
Healthcare providers and the general public are understandably reeling from all the information about various outbreaks of vector-borne infections. It's important to keep in mind 2 main points: 1) Nothing is happening this year that hasn't happened before in the US. This is the season for vector-borne viral infections. 2) Global warming has increased both the range of these vectors, introducing these infections to areas that haven't seen them in past years, and also increased the season length that these infections circulate. We could see increases in all these infections in coming years.
Here's a breakdown of some of the viruses being hyped in the news.
Approximately 70-80% of infections are asymptomatic. The most feared complication, neuroinvasive disease, occurs in <1% of all infections but has a 10% mortality and higher rates of permanent neurologic sequelae such as paralysis. So far in 2024, we have had 289 cases from 33 states in the US, with 195 being neuroinvasive (reflecting the fact that only the worst cases get tested for WNV, not any change in asymptomatic rates). Here are some maps for prior years in the US:
As of now, nothing out of the ordinary for West Nile disease in the US. But, it's pretty common if you recognize that we're only identifying maybe 1% of infections.
Here the risk is very high in Puerto Rico, but otherwise mostly restricted to travelers from the current epidemic/endemic areas. Some border states, especially Florida, are more likely to see autochthonous (locally acquired) cases. The asymptomatic infection rate is about 75%; 5% of the symptomatic infections progress to severe dengue with capillary leak syndrome and/or hemorrhagic complications. IMPORTANT CLINICAL PEARL: severe dengue usually appears when things otherwise look good - start of afebrile phase after 2-7 days of the febrile phase. This is the time to be very vigilant if dengue is suspected. The slide below (#42 in the pdf) is taken from a wonderful IDSA/CDC Clinician Call webinar this past week, available at https://www.idsociety.org/globalassets/idsa/multimedia/clinician-call-slides--qa/8-28-2024-clinician-call.pdf and https://www.idsociety.org/multimedia/clinician-calls/cdcidsa-clinician-call-update-on-dengue--other-vector-borne-diseases/.
Here are some numbers from the main CDC website above.
For 2024, the only locally acquired cases in the US have been in Puerto Rico (2676 cases), US Virgin Islands (85), and Florida (21), though those numbers are certain to rise since the season isn't over and reporting in general is delayed. If you add in the travel-associated cases, we've seen a little over 4000 in the US.
This is a relatively mild illness for the most part. The asymptomatic infection rate is around 40%, but 4% of those with symptoms will develop neuroinvasive disease. Now there is concern for vertical transmission in pregnant people, still not completely clear. Management guidelines for infants with possible intrauterine infection are updated and available.
Although I was aware of Oropouche virus previously, this is the first year I've ever heard of the term "sloth fever" which only applies if you acquire the infection in the jungle. This is a slide from that same IDSA/CDC webinar, slide 69 in the pdf.
Oropouche may be over with in South America now, and the main risk area remaining is Cuba. CDC reported 21 US cases in travelers returning from Cuba.
Saving the worst for last. It's very uncommon, but you definitely don't want EEE. The encephalitis picture occurs in <5% of those infected with EEE virus, but of those with encephalitis the mortality rate is 30%, and 50% of survivors have permanent sequelae.
We've had 4 cases in 2024 so far. Here's data from prior years:
This is a horrible disease. Certainly precautions such as mosquito spraying and personal protection from bites should be implemented in areas where the virus has been identified.
Earworms
Not wanting to end on a depressing note from the rare but severe EEE disease, I thought of earworms. I'm not referring to the real earworm infecting corn ears, nor RFK Jr.'s brain worm, but rather the more contemporary use of the term. Last week I went down the rabbit hole for the Maurice Williams song "Stay," and this entire past week I've been unable to get it out of my head. Maybe I'll replace it with "See You in September."
