September 2024 – Pediatric Infection Connection

Melanerpes carolinus

Bud WiedermannSeptember 29, 2024September 29, 2024Leave a comment

I just returned from a mad dash to Orlando, FL. No, I wasn't paying Mickey and Minnie a visit, just putting in an almost cameo appearance at the American Academy of Pediatrics National Conference and Exhibition. Apparently they were desperate for speakers because they invited me to give a talk about how to approach reading journal articles. A few dozen attendees politely endured my presentation, but I, and I think even most of the attendees, had a fun time. I also got to chat with a few old friends, always nice.

Although the trip was nice, I was most excited about the notice I received from my bird feeder while I was away. More on that later.

Potpourri

I came across a smattering of unrelated items this past week, grouped here.

I think we could all use some good news from the Middle East now. The WHO announced that Jordan has become the first country in the world to be certified to have eliminated autochthonous (locally-acquired) leprosy. That is no mean feat and required tremendous efforts and resources both from the country of Jordan as well as the WHO. It has been over 20 years since they've had an autochthonous case in Jordan.

The CDC has sent out a notice about mpox prevention through their Health Alert Network. It's not new, but worth reviewing to understand risk groups and to remind us to ask about international travel plans of our patients.

I've deliberately avoided commenting on the possible person-to-person spread of influenza A H5N1 in Missouri, but it's been in the lay press. Close contacts of 1 confirmed case had illnesses that could be consistent with this form of bird flu, but we don't have any test results from the contacts. I just mention it to stress that this is an evolving story. It would be a change for this organism if human-to-human transmission is now common.

Vaccine News

A couple intriguing reports last week from the CDC via the weekly MMWR. First are survey results that give us a glimpse at what happened with childhood immunization rates during the pandemic. It should surprise no one that vaccination coverage at 24 months of age declined by a few percentage points from birth year 2018-19 to birth year 2020-2021. For the combined 7-dose series (doesn't include covid vaccination) the rate dropped from 70.1% to 66.9%. This just adds to the possibility for sustained epidemics especially if clusters of poorly immunized children are grouped together. Here's a list of the national data for the 2020-2021 birth year cohort:

The entire table was too large to put in everything here, but Montana had the lowest numbers followed by California at second worst. You can look up your state and region in the article.

The same MMWR also had some new data on covid in children under 6 months of age. It provides compelling rationale for maternal immunization. First, here's what age-associated covid hospitalization rates look like from the surveillance network:

Further data showed that infant hospitalization rates are higher than rates in the elderly (75 years and above). In a subset of 1148 infant records that underwent extensive review, 9 deaths were recorded. Overall 22% of the hospitalizations involved intensive care admissions. Looking just at the 1065 infants for whom maternal vaccination status was available, it appears that maternal vaccination during pregnancy could be an important preventive measure for severe infant covid illness.

Note the careful wording: "No record of maternal vaccination during pregnancy." This points to the fact that these records might have been incomplete or even wrong - the providers may have recorded information incorrectly, or the mother may have been mistaken about vaccination status and timing. I'm still impressed with the information, especially since these numbers are very recent, from the omicron period when virtually every adult had some sort of immunity either via natural infection, vaccination, or both. Maternal covid vaccination is important to protect both the pregnant person, itself a high risk group, as well as the infant who is too young to receive covid vaccine.

A New Antiviral for RSV?

A placebo-controlled, randomized, double-blind trial of a few hundred infants hospitalized for RSV in China suggests that a newer antiviral agent, ziresovir, might be an effective treatment.

The main endpoint is change in the "Wang score" which is a relatively unvalidated scoring scale for assessing RSV severity. You can see the decline in the score is a bit better with the treatment group compared to placebo, but is the change in score clinically important? As a still wet-behind-the-ears ID attending, I witnessed early studies of randomized, double-blind, placebo-controlled trials of aerosolized ribavirin for hospitalized infants with bronchiolitis; my boss, a renowned pediatric infectious diseases physician named Bill Rodriguez, headed up these multi-center studies. I witnessed potential pitfalls in using scoring systems for bronchiolitis, particularly the problem with intra- and inter-rater reliability in assessments: it's hard to be consistent with scoring when the events you're looking at are somewhat subjective. Also, the aerosolized ribavirin left a fine powder on the infants, difficult to disguise even when the nurse tried to remove it before the investigator did the scoring. So, it wasn't perfectly double-blinded, in some cases not blinded at all. At blinding wasn't a problem with ziresovir, which is administered orally. Aerosolized ribavirin did work, but ultimately the costs outweighed the benefits (plus some risk to providers of inhaling the medication if the patient room was not well-ventilated and potential for teratogenicity), so the practice didn't last long.

I'll wait to see more data about this intriguing new agent. In the meantime, remember we have very effective methods of preventing severe RSV disease in infants by either maternal vaccination or administration of long-acting monoclonal antibody (nirsevimab) to infants whose mothers were not immunized.

Crystal Ball Time

What's coming this winter, and how bad will it be? Don't place any big bets on the CDC's latest predictions, they have only low to moderate confidence with their model, but it's by far the best data we have.

Here goes: "CDC expects the upcoming fall and winter respiratory disease season will likely have a similar or lower number of combined peak hospitalizations due to COVID-19, influenza, and RSV compared to last season."

That's good news. The experts were moderately confident of predictions for individual infections, but it's not really possible to anticipate all of the variables that could change the predictions dramatically, such as immunization uptake. Of course, if a new covid variant arises with a very effective immune escape mechanism, no one will be betting and we'll be in for a bad time.

Here's some more tidbits:

For example, if our summer covid activity peaks early (which it seems to be doing), they predict a milder winter season than if covid continues to rise now.

If you're a nerd like me, you can look at their description of how they developed this prediction model.

For the Birds

Getting back to my bird feeder, regular readers will recall my travails discussed in prior posts, including battling squirrel seed raiders. Things have settled down now, and I seldom see new species, but the past 2 days I've had my first sightings of a red-bellied woodpecker. The first thing I noted from my feeder's video (still photo taken below) is that I don't see a prominent red belly.

Other views show the typical zebra-like striping on the wings - why not call it the zebra woodpecker? - and the Cornell app quickly identified its call as the red-bellied variety. As usual, I couldn't help but see what new woodpecker tidbits I could learn from the worlds of literature and music. My childhood and adolescent "career" playing tenor saxophone made me a fan of big band music, particularly of Glenn Miller, and I discovered he had recorded The Woodpecker Song. It's not that great in my opinion, but at least I learned something new. One of my other musical heroes, Chuck Berry, recorded a purely instrumental (with saxophone solo!) song called Woodpecker. My favorite find, though, was a new-to-me poet, Elizabeth Madox Roberts. She was a Kentucky-born daughter of a Confederate soldier, active as a poet and novelist in the late nineteenth and early twentieth centuries. She seems to have the largest numbers of poetry web sites extolling her virtues for poems about woodpeckers. Here's her poem The Woodpecker in its entirety:

The woodpecker pecked out a little round hole
And made him a house in the telephone pole.

One day when I watched he poked out his head,
And he had on a hood and a collar of red.

When the streams of rain pour out of the sky,
And the sparkles of lightning go flashing by,

And the big, big wheels of thunder roll,
He can snuggle back in the telephone pole.

Happy Autumnal Equinox 2

Bud WiedermannSeptember 22, 2024September 22, 20242 Comments

It's been an eventful week for me but relatively quiet in the world of infectious diseases. I've just returned from a week's trek in the semi-wilds of Colorado. You may recall that last week's post included a mention of mosquitoes and high altitudes, noting that climate warming has been accompanied by trends of more mosquitoes at those upper elevation. I'm happy to report that after spending the week in the great outdoors at 5000 - 10,000 feet I only had a few bites and didn't even touch my insect repellent.

Turning skyward, I was able to view the September 17 partial lunar eclipse from Mesa Verde National Park; sadly my antique cell phone camera was unable to capture it. This morning I consulted my trusted 2024 print edition of The Old Farmer's Almanac to remind myself of the difference between an equinox and a solstice. The earth's axis is tilted at 23.5 degrees from the perpendicular as it revolves around the sun, and the equinoxes occur when both northern and southern hemispheres equally face the sun. Northern hemisphere solstices occur when the North Pole is most tilted towards (winter) or away (summer) from the sun. I learned so much this week!

Pertussis

Whooping cough was in the news recently, though really this is just a return to "normal" after the pandemic years. Here's the long view from CDC data.

On a more recent view, you can see the age breakdown.

I was involved in pertussis immunology and vaccine research very briefly in my career. I always like to mention an oldie-but-goodie article from 1992 showing that about one-quarter of UCLA college students with cough lasting longer than 5 days showed evidence of recent pertussis infection. It's a good reminder that pertussis in adults usually looks very different, and milder, than the classical whooping cough in infants. Diagnosis is difficult unless you think about pertussis as a possbility.

Maybe not so coincidentally with these news reports, the FDA VRBPAC meeting last Friday focused on using Controlled Human Infection Models (CHIMs) to try to develop a better pertussis vaccine. Yes, that's right, intentional infection of human volunteers to study various aspects of the disease. We need more information to improve pertussis control, given that our current acellular vaccines are less effective (but also with less side effects) than the predecessor whole cell vaccines. Large scale trials are difficult, expensive, and largely impractical in the present era, so it's time for new approaches. A group at the University of Southhampton in the UK presented some preliminary data from a CHIMs trial and also had a nice graph to put into perspective relative mortalities and contagiousness of pertussis compared to other pathogens:

The study itself was just a challenge study of human volunteers to determine the dose of organisms and the immunologic responses surrounding infection and colonization. It seems likely that these types of studies will be utilized more frequently in the future to improve our understanding of pertussis prevention.

Needless to say, I didn't join this meeting live, I was off the grid in Colorado, but I did skim through the recording and slides today. This wasn't a typical VRBPAC meeting where voting occurred, it was more of a discussion to guide future research.

More Wastewater

Speaking of returning to pre-pandemic levels of infection, I've been watching wastewater trends for enterovirus D68. You may recall that this was an enterovirus strain that figured prominently, but not exclusively, in outbreaks of acute flaccid myelitis that tended to occur in even-numbered years - pretty strange.

As you can see, the pandemic really ended this pattern, and nothing new is going on so far this year. However, wastewater numbers, at least for EV D68, have looked very different.

Will we see a blip upwards in AFM cases this year? I hope not.

More Colorado Learning

My landscape designer wife clued me in to the details of the quaking aspens, so named due to the fluttering of the leaves that have their own distinct sound. They are beautiful, both my wife and I wished we had better pictures to show you.

On another note, although I love to learn, one new factoid I happened upon was perhaps less exciting. Hiking at these altitudes, I learned that I'm not as young as I used to be!

Invasive Species

Bud WiedermannSeptember 15, 2024September 15, 2024Leave a comment

Last week I outsmarted myself. The closing photo in the September 8 blog I was sure would result in at least 1 person calling me out; I was then going to follow up in this week's post to explain about invasive species. I guess I forgot to factor in the politeness of my audience in not wanting to berate me for mistakes. (This is a more preferable explanation than the alternative that no one even read that post!)

Still not much going on with our summer respiratory season. The percentage of ED visits due to covid continues to fall nationally.

However, covid wastewater levels in the western US plateaued or even increased a little.

Measles Still Here

It looks like we have settled into a persistent trickle of cases in the US. I'm still holding my breath hoping we can avoid another major outbreak this year. The official tally for 2024 now is 251 cases from 30 states and DC.

Not included in the totals above is a new case occurring in an unvaccinated student at Western Kentucky University, probably acquired during international travel. It looks like that person attended several public events over a few days in late August; with an incubation period of around 2 weeks, we should be hearing soon if secondary cases resulted from this person.

Meanwhile, the UK has reported a measles death in a "young person who was known to have other medical conditions." With 2465 confirmed measles cases so far this year, the UK is much worse off than we are in the US. Still, it's unsettling to hear about measles deaths in high income countries. The UK has had 1-5 deaths per year since 2019 but hasn't had double-digit death figures since 1988. Best estimates are that, even with the best medical care, 1-3/1000 children with measles will die.

A Couple Vaccine Updates

Nothing really new here, but it's easy to overlook important guidance with the flood of emails and other reminders we receive. First is the official statement from ACIP about Hib vaccination for American Indian and Alaskan Native infants. It is the follow up from an ACIP meeting last June. For both socioeconomic and biologic reasons, it's been clear for decades that this population has a very high rate of Hib disease and also a less robust response to most Hib vaccines compared to the general US population. The best Hib vaccine for this group is a conjugate using the Hib polysaccharide PRP joined to an outer membrane protein from Neisseria meningitidis. The OMP is a carrier protein that helps infants form antibody to PRP, the real protective antibody here. This is the basis for all conjugate vaccines; it fools the infant immune system into thinking it is seeing a protein antigen rather than a polysaccharide antigen; PRP and other polysaccharide antigens are not well recognized by infant immune systems - normal infants even fail to form antibody to PRP with natural Hib disease. Conjugate vaccines fool infant immune systems.

At any rate, for a long while we've only had 1 Hib vaccine with the PRP-OMP combo: PedvaxHIB. This summer we saw FDA approval of Vaxelis, a hexavalent vaccine with DTaP, IPV, HepB, and Hib, the latter using the PRP-OMP product. Vaxelis is now officially recommended as an option for the AI/AN infant population, as well as for other infants. The recommendation for the AI/AN group was made on the basis of a phase IV randomized study of Vaxelis versus PedvaxHIB showing good antibody formation in both groups. No effectiveness study was performed because this population didn't have enough Hib disease present at a background rate to determine any significant differences with a new vaccine - PedvaxHIB has worked very well for these children in the past, another vaccine success and cause for celebration.

A second vaccine update is just the recommendation, again from CDC, for the next round of covid vaccines recommended for everyone 6 months of age and older. Again, nothing new, but it's a good resource to have all that information in one document. The tables serve as a quick reference for many different situations.

Mosquito Invasion

Any ID physician worth their salt will obtain an extensive travel history when seeing patients. We are mostly looking for clues to diseases seen mostly in international travelers, such as typhoid fever and the vector-borne infections that include dengue, chikungunya, malaria, and others. However, sometimes the travel history is negative but the patient ends up having one of those exotic diseases, acquired locally in the US (aka autochthonous infection). Such is the case recently with autochthonous dengue fever cases in Los Angeles County, CA. These cases appear when there is an existing reservoir of infected people plus a reservoir of the vector. For dengue virus, the vector is the Aedes mosquito, specifically A. albopictus and A. aegypti, plentiful in much of California.

The range of these mosquitoes have been increasing the past few decades at least, mostly due to warming of our climate. The last extensive study of Aedes presence in the US was in 2017, summarized by CDC.

As one of those people who seem to be particularly tasty for mosquitoes, I find it interesting (and depressing) that we have about 200 different species of mosquitoes in the US. I'm not terribly comforted by the fact that only about a dozen of these can transmit those infections we worry about. Besides the Aedes genus, we also need to worry about Anopheles and Culex mosquitoes.

Of these, it is Aedes that is the most versatile in transmitting disease to humans, implicated in Cache Valley virus disease, chikungunya, dengue, eastern equine encephalitis, La Crosse encephalitis, and zika infections. Anopholes can spread Cache Valley virus, and Culex are implicated in eastern equine encephalitis, St. Louis encephalitis, and Oropouche virus, though midges more commonly spread the Oropouche. Other viruses such as Jamestown Canyon virus can be spread by many different species of mosquitoes and vary with time of year and location.

As our global temperatures have warmed, the mosquito season has lengthened; in many locations mosquitoes are out and about throughout the year. Also, the idea that high altitudes are safer from mosquito-borne infections is becoming invalid in many parts of the world, including the US. It wasn't the altitude per se that mosquitoes didn't like, it was the cool weather which now is warming.

I realize that for many of you this is already too much mosquito information, but if you want more visit Arbonet.

More Invasion

Getting back to last week's post, I had mentioned that my wife was outside working hard to clear our back yard of poison ivy while I was indoors typing leisurely. It turned out she didn't find any poison ivy. The photo I placed at the end of the post wasn't poison ivy but rather a portion of the massive porcelain-berry plant she removed instead. While poison ivy is a native plant, not invasive but still hated, porcelain-berry is a horribly invasive vine deliberately introduced into the US for its attractiveness but quickly discovered to spread indiscriminately, eliminating native vegetation in its path. It is the plant world equivalent of pod people.

Tirade Time

Bud WiedermannSeptember 8, 2024September 8, 2024Leave a comment

It's unusually cool today in the Washington, DC, area, prompting my landscape designer wife to don her poison ivy hunting apparel and venture into the nether regions of our back yard to keep it safe for us.

We've had a lighter week in infectious diseases events. I'll take advantage of that to share a rare criticism of one of my favorite ID feeds. But first .....

Leptospirosis

This is a tough diagnosis most of the time; it's a relatively uncommon infection in the US, and the early stages don't have particularly novel signs and symptoms; it's just a nonspecific febrile illness. About 10% of cases can progress to a second and more severe stage, often called Weil's disease. It's important to remember that it can be a water-borne pathogen, as illustrated by these 2 recent reports.

First, this week's MMWR provides us with documentation of the leptospirosis outbreak in Puerto Rico following Hurricane Fiona in 2022. Leptospirosis is endemic in parts of Puerto Rico, and a disruption like flooding due to a hurricane increases its reach and can result in disease spikes. Look at these graphs of weekly rainfall and leptospirosis cases - it certainly fixes in my mind the tie between water and leptospirosis.

The MMWR article has a link to a nice clinician fact sheet.

Similarly, there's a new spike in leptospirosis infections in Thailand, so far just in news reports (you'll need Google translate again).

I first took a deep dive into leptospirosis as a medical student when I came upon a landmark article of detective work surrounding an outbreak in St. Louis. Two of the authors were mentors of mine, and they loved to regale me with (probably augmented) tales of tracking rats through the sewers of St. Louis. I'm sure this contributed to my choice of pediatric infectious diseases as a career, though not to the extent that I've chased sewer rats.

Mixed Messages About Vaccine Protection From Long Covid

A new article reached a different conclusion from several other reports showing that covid vaccination is somewhat protective against long covid, now better termed PASC (Post-Acute Sequelae of COVID-19). The new study is a retrospective cohort study mining an administrative database from a single (large) healthcare system. The bottom line is (of course!) towards the bottom of the table: no real differences in PASC rates based on vaccine status. Also note this was primarily a study of adults.

Is this a flawed study? Are the authors' conclusions wrong? Well, no to both. We will have differences in conclusions from such studies primarily when we are seeing retrospective studies that rely on administrative databases. The authors did a heroic job of attempting to adjust for various errors in how such data is recorded, but it's impossible to account for everything. Thus, we can have errors in diagnosis, diagnostic code assignment, and missing data, among other issues. Couple that with different definitions of PASC and the likely heterogenous pathogenesis of different forms of PASC, and it's a recipe for conflicting study results. I think we likely will have a clearer picture of PASC, including whether covid vaccination can offer some protection, but it will take prospective longitudinal studies which require more time for data collection and analysis. A longer discussion of the science of PASC is reviewed in Nature Medicine. In the meantime, studies like this one help us fine tune future studies.

Shame on CIDRAP

CIDRAP (Center for Infectious Disease and Research Policy at the University of Minnesota) is one of my favorite daily feeds. I think they blew it in mentioning FDA clearance of a new Lyme test; not only is it not newsworthy, but it could lead some individuals to chase harmful Lyme disease testing. I could be guilty of the same by even mentioning it here.

First of all, FDA clearance of diagnostic tests is a relatively low bar to clear. Although I couldn't find any FDA commentary on the test in question (I guess that would require a Freedom of Information Act request), I did link to the criteria that I think likely were used in this setting, because the particular methodology this test utilizes is nothing new. So, I believe the manufacturer would only need to show "substantial equivalence" to existing tests. This is not the same as showing the new test improved diagnostic accuracy or improved healthcare outcomes. Here's the summary of applicable FDA guidance:

"Studies to Demonstrate Substantial Equivalence

The types of studies typically used to demonstrate substantial equivalence may include the following:

In the majority of cases, analytical studies using clinical samples (sometimes supplemented by carefully selected artificial samples) are sufficient.
For some IVDs, the link between analytical performance and clinical performance is not well defined. In these circumstances, clinical information may be warranted.
FDA rarely requires prospective clinical studies for IVDs, but regularly requests clinical samples with sufficient laboratory and/or clinical characterization to allow an assessment of the clinical validity of a new device. This is usually expressed in terms of clinical sensitivity and clinical specificity or agreement."

This new Lyme test is simply an immunoblot, a very common type of test utilized in multiple settings but with the drawback that interpretation is somewhat subjective - a human needs to decide if a band is prominent enough to be considered present.

When I dug deeper to find supporting studies for this particular test, I became more alarmed. While there are some preliminary studies that I think might have used this new immunoblot method, they don't answer any clinical performance questions. More worrisome is that the test will be sold by a California lab called IGeneX, a company that offers many Lyme tests that, in my opinion, have falsely diagnosed many of my patients with Lyme disease. They often rely on their own interpretations of what constitutes a positive test and provide no reliable scientific evidence to suggest their methodology is valid. In fact, the press release for this new test stated that "Results interpretation is based upon new criteria and not CDC criteria."

Even now on their website they steer providers and patients away from the standardized two-tier testing preferred by CDC. Here's a quote from the IGeneX website: "Lyme disease is typically diagnosed by a two-tiered testing (TTT) approach involving an enzyme-linked immunosorbent assay (ELISA) followed by a Western blot test. However, the sensitivity of these commercially available tests is poor, meaning they can miss active infections. Experts advise against this testing technique due to the ambiguity of its results." It's easy to find a so-called expert to say anything. Again, in my opinion, this lab is to be avoided, and you'll notice I didn't provide a link to them. I'm disappointed CIDRAP gave them free publicity.

Lyme disease testing is far from ideal, and it's certainly possible this new test is an improvement, though I doubt it. CDC explains diagnostic testing for Lyme disease, including the recommended two-tiered testing options. I suspect IGeneX might try to claim that their new immunoblot can fulfill CDC recommendations, but I'm concerned that they will use unsubstantiated rules for interpretation of a positive immunoblot result, as they have for similar tests in their lab.

COVID Crystal Ball

Last week my wife and I got our new covid vaccines, more based on upcoming travel plans rather than any immediate concerns about getting covid. In fact, things seem to be winding down. According to the latest CDC clairvoyance, "we estimate that COVID-19 infections are growing or likely growing in 7 states, declining or likely declining in 16 states, and are stable or uncertain in 25 states." (Not a totally reassuring conviction if half the states could be uncertain!)

I couldn't find a separate precise definition of cutoffs for their categories, but from viewing the data it appears that the Stable or Uncertain category is defined as a probability that the epidemic is growing in those states as between 0.5 and 0.75. By comparison, all the Growing states had probabilities of 0.93 and above.

Curmudgeon-in-Residence

I think I've paid my dues long enough to be entitled to curmudgeon status. The new Lyme test thing reminded me of my dismay that some of the children I've seen in my practice over the years were harmed by use of misleading diagnostic tests resulting in prolonged and unnecessary antibiotic use. I wear my Statler and Waldorf credentials proudly. I think I bear more of a resemblance to Statler.

Now, to cool off a bit, I'll take a quick stroll in my (safer) back yard.

Seeing You in September

Bud WiedermannSeptember 1, 2024September 2, 2024Leave a comment

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.

West Nile Virus

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.

Dengue

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.

Oropouche Virus

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.

Eastern Equine Encephalitis

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."

Month: September 2024