You know things are slow in my world if I'm mentioning pestes des petits ruminants, aka goat plague, but it has been in the news lately and does have relevance to us. Spoiler alert, you don't need to break out the masks and gloves, the virus causing this disease has never been reported to infect humans.
We're talking primarily about covid and avian flu at the moment. Covid wastewater levels may be starting to level off, except in the southern US.
The clinical respiratory illness map is a beautiful sea of green (with a bit of light green in Alaska). I'm only showing this to remember fondly come next winter.
Not a lot to report on the avian flu front, with a continued sprinkling of new mild human illness in poultry/dairy workers and new outbreaks in flocks and herds. I was interested to see that CDC is making a $5 million investment to provide seasonal flu vaccine to at risk workers. Of course we want everyone eligible to vaccinate themselves against seasonal influenza, but the ulterior motive here is to lessen the chance that a human will be simultaneously infected with a seasonal flu strain along with the influenza A H5N1 avian strain. Such a situation could increase the likelihood of reassortment of the 2 strains to create a new virus that could cause more problems for us. This scenario is still a rare probability but worth preventive measures.
PPRV and Cousins
The virus that causes PPR is a morbillivirus, which should sound familiar to healthcare providers because that is the same genus as measles virus. You can learn more than you want to know about PPR from the article from which the figure below was lifted.
Morbilliviruses in general have the theoretical ability to be eradicated. In fact, one animal morbillivirus, rinderpest virus, already has been eradicated. PPR has been targeted for eradication by 2030, but a recent outbreak in Greece now threatens that with spread from Africa and the Middle East to the European Union. Infection has a very high fatality rate in goats, sheep, camels, and other ruminants that provide livelihoods to many. So, although PPRV doesn't infect humans, runinant infection is a major threat to livelihoods of those in these countries who depend on these animal industries. The World Organisation for Animal Health nicely summarizes eradication tools in place, let's hope the Greek outbreak doesn't set eradication plans back too far. (Also, if you're looking for a rabbit (only slight pun here) hole to fall down, check out WOAH's list of 207 animal diseases.)
The real reason I mention PPR is to draw attention to somewhat misleading measles pronouncements in the lay press this past week. NBC, among virtually every national news agency I could find, highlighted the CDC announcement that US measles cases have tripled this year compared to all of 2023. That's true but also misleading. I understand this helps get the message out that measles vaccination rates are low in many segments of society, but by using this relative increase in cases as a headline it overlooks the fact that the actual number of cases is still low, thank goodness. To its credit, the NBC link above did go on to give these details, but in our sound bite world that clarification is easily lost. Here's a bit more perspective from CDC.
From the same website, you can see how graphs can be used to stress a particular point - the perspective below would make us think everything is great. Just by expanding the date range, we can hardly see anything going on this year.
CDC regularly updates assessments of measles outbreak risk in the US. Currently they predict the most likely number of cases for 2024 will total 300, with a 4% risk of >1000 cases. Keep that in mind over the next 5 months.
Don't get me wrong, I'm all for increasing measles vaccination rates; however, I don't want to do this without presenting an accurate view of the data. I'd make a terrible salesperson or politician.
The one or two regular readers of this blog know that I'm a favorite companion at outdoor summer activities, not because of my scintillating conversational repartee but rather due to my fabulous mosquto/gnat magnet properties. No one near me needs to worry about bug bites; all those bloodsuckers are feasting on me. One morning this week I gathered a couple dozen bites in a very short time and have been scratching ever since. I've been waiting for symptoms of West Nile virus infection, nothing so far. Meanwhile, another vector-borne disease may have worse consequences than previously known.
But first, ...
Covid Summer Surge
In spite of many breathless news reports, this is still nothing to get worked up about, other than for high-risk individuals to consider returning to masking in crowded indoor spaces and employing other mitigation strategies. Some of the lay reports seem to forget that wastewater levels are not the same as actual infections. Wastewater covid detections might be decreasing, especially in the West.
Percentage of emergency department visits due to Covid, one rough measure of clinical illness, is increasing though still at low levels.
Meanwhile, we have a little more clarity on one aspect of long covid. In one study, myalgic encephalitis/chronic fatigue syndrome in adults was no more common following covid than following an acute infection-like illness that was negative for covid. I've long been concerned that case definitions and studies haven't been focused on the heterogeneity of long covid. Fortunately, some studies are geared to looking at the ME/CFS cases separately from post-covid symptoms that might be related to end-organ damage persisting after severe pulmonary or other infection.
Avian Flu
Similarly, the highly pathogenic avian flu A H5N1 continues to crop up in dairy and poultry workers but doesn't seem to represent a broad risk to others, with no known human-to-human transmission. I neglected to mention last week some preliminary results from the seroprevalence study in Michigan dairy workers: none of 35 tested workers had antibody to the virus, suggesting that asymptomatic infections aren't common. However, we need a sample size larger than 35 to get a better handle on this.
Last week's MMWR contained a report supporting the impression that this particular avian flu strain in humans is a very mild disease.
Wash Your Parsley
Did you know that the FDA performs regular microbiologic surveillance sampling of foods? Last week they reported results from sampling of basil, parsley, and cilantro, 3 of my favorite herbs. Below are numbers for the prevalence of various pathogens in different herbs; 95% CI are in parentheses.
Herb
Cyclospora cayatenensis
Salmonella spp
Escherichia coli
Cilantro
9.2% (4.4-16.5)
2.8% (1.1-5.7)
0% (0-1.5)
Parsley
1.3% (0.5-2.6)
0.9 (0.4-1.8)
0.1% (0.4-1.8)
Basil
0% (0-2.6)
0.7 (0.1-2.7)
0.7% (0-1.4)
For comparison, grocery store Salmonella spp. contamination rates for chicken vary from about 8 to 24%, depending on the study.
Want Some Listeria With Your Liverwurst?
CDC has been investigating a Listeria outbreak linked to deli counter sliced foods, and now one brand of liverwurst tested positive for Listeria. It's possible that a single product could have contaminated slicing devices, causing Listeria to end up in other deli foods. I hope your favorite deli counter practices good cleansing practices for their slicing machines. If not, you might get a side of Listeria with other deli products too.
Ever Heard of Oropouche?
Probably not, unless you are an infectious disease nerd or familiar with the island of Trinidad or the Amazon basin. Oropouche virus (OROV) is still known by the old practice of using a geographic term to name it Now we have new attention focused on this virus, previously thought to cause a relatively harmless though uncomfortable febrile illness. It was first discovered on Trinidad in 1955, in a forest worker from Vega de Oropouche, Trinidad. OROV is endemic to the Amazon basin, and Brazil is seeing a big upsurge in Oropouche fever this year.
With that have come some troubling new reports. OROV is an arbovirus related to dengue, and it mostly causes an acute febrile illness with sometimes very painful myalgias, similar to dengue, zika, chikungunya, malaria, and similar infections. It is transmitted primarily by Culicoides paraensis, a biting midge, but also can be transmitted by other biting insects including Culex mosquitoes.
Last week the Brazilian health ministry confirmed 2 deaths from Oropouche fever, both in healthy young women. The clinical descriptions resemble dengue hemorrhagic fever. Also, the Pan American Health Organization is investigating possible vertical transmission of the virus from 2 infected mothers. One pregnancy resulted in miscarriage, the other with intrauterine fetal death. PAHO has issued guidelines for evaluating possible vertical transmission of OROV. These studies should help us understand if OROV is similar to Zika virus's ability to cause fetal malformations and other severe outcomes. [Note that you may need to activate Google Translate to read these links.]
Meanwhile, I haven't seen any C. paraensis around my house.even though they do range into the northern US, including Maryland. They are pretty tiny, can be less than a millimeter, so good chance I would miss them. I'm somewhat curious to know if I'm also a midge magnet, but really I'd rather not find out.
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.
Now we can add a fourth case this year of avian flu in a human residing in the US, again a mild case with conjunctivitis in an individual in close contact with infected dairy cows. No surprise there, but I'm waiting to see what happens with all the summer state fairs that provide more opportunities for human exposure to infected poultry and mammals.
Summer Covid Watching
The bottom line in the US is that covid infections are likely still pretty low, and we don't really know if we'll see a significant surge in the next few months. Any prediction is harder these days because our monitoring systems are probably the worst they've been in the past 4 years. On a national public health level, post-pandemic reporting and tracking have been relaxed and made voluntary, which for many healthcare institutions and jurisdictions can mean no reporting at all. On an individual level, people are less likely to seek testing or treatment, probably due to a combination of numbness from years of being on the edge plus relatively lower disease severity.
I'm focusing on a few data sites.
First is the CDC's Respiratory Virus Weekly Snapshot. The percentage of positive tests sheds some light in disease activity, still cloaked in individual behaviors in seeking testing in the first place and lack of reporting from most home testing. The recent covid percentage is trending up, though not at the level of fall 2022.
Covid wastewater trending is helpful and perhaps the least altered by changes in practice over time. Unfortunately, vast areas of the country have no reporting. Activity levels are rising particularly in the western US, but still well below prior surges. I noted that wastewater updating took a holiday last week, so we're missing the most recent numbers.
Second, I'm keeping a watch on relative predominance of different variants, with an eye to how effective our next vaccines will be. The top 4 variants currently are KP.3, KP.2, LB.1, and KP.1.1. Any late summer or fall surge likely would include one or more of these. I'm waiting for more data on how well serum from recipients of the new vaccines will neutralize these variants in vitro.
Should I Change My Annual NJ Beach Trip?
A flurry of beach closings due to poor water quality last week. I couldn't find any national consortium on this, so you'll need to look at specific states to find out what's going on at your beach rental house this summer. In my browsing I particularly liked the Massachusetts interactive water quality dashboard; Massachusetts seems to be one of the harder-hit states.
The song I Ain't Worried was written for the beach football scene in the movie Top Gun: Maverick. It was conceived early in the pandemic (when we were worried!) and was an upbeat breather contrasting with the intensity in the rest of the movie. Not a bad antidote for your summer worries, whatever they may be.
My long-suffering (try putting up with me for 40+ years) wife, a retired general pediatrician, thought my posting about the FDA VRBPAC meeting was a bit too detailed for front-line healthcare providers. Reading it again, she's right, but of course I'll push back a little bit given that FDA has backtracked on the committee's recommendation. First, a few other updates.
Wild-type Polio Update
Thankfully we haven't had any recent polio appearances in the US, but it's a bit discouraging to see what's going on worldwide. The Global Polio Eradication Initiative reported 1 case of wild-type polio in each of 2 countries, Afghanistan and Pakistan. Here's the complete list for the week which includes vaccine-derived cases and environmental sampling as well:
Afghanistan: one WPV1 case
Pakistan: one WPV1 case and 20 positive environmental samples
Côte d’Ivoire: three cVDPV2-positive environmental samples
DR Congo: one cVDPV1 case
Ghana: one cVDPV2-positive environmental sample
Liberia: four cVDPV2-positive environmental samples
Niger: one cVDPV2-positive environmental sample
Sierra Leone: six cVDPV2-positive environmental samples
South Sudan: one cVDPV2 case
Yemen: three cVDPV2 cases
Remember that paralytic polio cases represent only the tip of the iceberg for polio infections; the vast majority of infections are asymptomatic, with a few percent manifesting as nonspecific febrile illnesses. Paralytic polio cases comprise less than 1% of infections. So, the appearance of 1 case can imply that at least 100 more infections were present in an area.
Can Infants Spread C diff in Households?
Asymptomatic Clostridioides difficile carriage is common in infants, and the organism seldom causes illness under 2 years of age. That's why you don't want to test for C diff in younger children. An interesting new study suggests, but by no means proves, that these asymptomatic carriers might be the source of household spread which could include spread to more vulnerable individuals.
Thirty families were recruited at their child's 4-month checkup to participate in this longitudinal study where participants mailed soiled infant diapers every 2 weeks to the study site, until the infants reached 8-9 months of age. Rectal swabs from mothers, and sometimes from fathers, were mailed at the same time but in separately sealed containers. (Sorry, but I couldn't help but wonder if the mail carriers had to put up with some unusual package odors!) The specimens were tested for C diff and positive samples were strain-typed and tested for toxin production.
Probably the researchers would have needed to perform more frequent sampling to prove the directionality of transmission, i.e. infant to adult or vice-versa, but they did note that the adults, compared to the infants, seldom were the initial positive carriers in these families. Sharing of C diff strains in the families was common and more often implicated infant to adult directionality. C diff prevalence in infants was 50.0-71.4%, including nontoxigenic strains, while maternal positivity was 20.0-40.0% and fathers were 20.0-37.5% positive. None of the infants or parents developed symptoms.
Something to keep in mind, but please don't start testing infants for C diff.
Misinformation Tracking
A recent article tried to look at patterns of misinformation and flagged content on Facebook. Unfortunately subscription is required for full article access, but the abstract is an accurate summary. Based on numbers of pageviews, the authors felt that unflagged content on Facebook was more likely to be influential.
The authors used a complicated (to me) combination of crowd-sourcing and machine learning to derive estimates of vaccine hesitancy and matching to pageviews. They concluded "...We estimate that the impact of unflagged content that nonetheless encouraged vaccine skepticism was 46-fold greater than that of misinformation flagged by fact-checkers." This unflagged content predominantly consisted of real facts, e.g. rare deaths following vaccination, that then were misinterpreted by viewers as the vaccine causing the death rather than within the expected death rate based on the general population, regardless of vaccination status. A classic misinterpretation due to lack of a control group!
Along the same lines, I noted with sadness that the Stanford Internet Observatory that tracks misinformation is shutting down, in large part due to lawsuits and online attacks received by staffers. Enough said.
The Flu Front
Not to be overly concerned, but a brief CDC report demonstrated spread of neuraminidase mutations in influenza A H1N1 strains in the US, showing reduced susceptibility to oseltamivir. We'll hope these don't become more common.
On the positive side, a NEJM article demonstrated that heat readily inactivates the current influenza A H5N1 strains showing up in cows' milk. I didn't see any earth-shattering news on H5N1 in the past week, but I happened upon the AAP Red Book's outbreak pages for the topic and really liked their bullet summary for current status in different populations:
People: 3 cases (in 2024) Person-to-person spread: None Current public health risk: Low Dairy Cows: Ongoing multi-state outbreak Wild Birds: Widespread Poultry Flocks: Sporadic outbreaks Mammals: Sporadic infections
Apparently these outbreak pages are free to the general public, so check it out. (IMHO every pediatric healthcare provider should have a Red Book subscription, included in AAP membership.)
Covid Vaccine Backtracking
Initially following the FDA VRBPAC meeting on June 5, FDA recommended that the JN.1 covid strain be utilized in the next iteration of covid vaccines. On June 13 they amended this, stating that "if feasible" the KP.2 subvariant should be used instead. What's going on?
After a day-long discussion, the VRBPAC members were asked to vote on whether or not to choose a monovalent JN.1-lineage strain to use in the next vaccine. The vote was unanimous in favor of this. As seen in the section of the lineage chart below, the JN.1 lineage includes that purple JN.1 strain at the left, as well as all the subvariants derived from it.
The VRBPAC vote didn't specify which of all those strains to pick. The discussion following the vote did address that, with the important concerns being whether newer subvariants like KP.2 and KP.3 might be dominant this fall and could evolve further to be more antigenically distinct than JN.1. In that scenario, a JN.1-based vaccine might be less effective. On the other hand, KP.2 might prove to be a worse choice if its derivatives became more antigenically distinct from other subvariants that might predominate in the fall. This is too tough to predict now. (I was also interested that CDC stated they aren't emphasizing research on using generative artificial intelligence as a predictive tool.)
I was monitoring the VRBPAC meeting in real time, and it was clear that Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, leaned more towards using the KP.2 subvariant, and I guess eventually this view prevailed. I'm not quite clear why the initial guidance didn't say that since I don't see any startling new information this past week. Here's the latest variant picture from the same link as above.
As always, the last 2 fortnight periods are only estimates; in the past, these estimates have been fairly accurate predictors. The 6/8/24 bar isn't that different from 5/25/24 in that KP.2, KP.3 and LB.1 seem to be trending towards dominance while JN.1 itself fades. It's important to remember that in general across the US covid activity is pretty low, with a few spots of minor uptick but nothing approaching a big surge so far.
Shifting towards the KP.2 variant as the vaccine component won't affect the Moderna and Pfizer planning, they were already working on both JN.1- and KP.2-based vaccines. However, Novavax won't be able to supply a KP.2 vaccine for another 6 months. They would however be able to have a JN.1 vaccine by fall. That "if feasible" phrase in the FDA announcement seems to leave the door open to allow Novavax to continue with JN.1 vaccine production; the company submitted an FDA application for authorization of this vaccine on June 14, the day after the new FDA announcement. I'll be interested to see how the discussion goes at the CDC ACIP meeting in a couple weeks.
The Eight Queens Puzzle
I was looking up the term backtracking to see where it came from (apparently it showed up in 1870), but instead found another use of the term in computer science, specifically computer algorithms. That led me to the eight queens puzzle.
Apparently there are 92 separate solutions to this puzzle, first published in 1848. Subsequently the puzzle was expanded to all natural numbers, the n queens puzzle, for which solutions exist for all of them except the numbers 2 and 3. The chessboard then has n rows and columns. This is a dangerous rabbit hole into which I hope I never fall.
Happy Father's Day to all you dads, granddads, step-dads, and every other iteration!
