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!
The 33rd edition of the American Academy of Pediatrics' 2024-2027 Report of the Committee on Infectious Diseases, aka Red Book, arrived online (and on my doorstep) recently. This latest edition adds about 100 pages to the 32nd edition, even as many sections were combined or shortened. More than annual spring cleaning, this is a renewal effort for me that has become an enjoyable triennial task for me. Although the early pages provide a brief summary of changes (total 222) from the previous edition, I operationalize this by having the new Red Book at my side always, looking up every clinical situation I encounter in reading or in patient care. Not surprisingly, even after doing this for maybe the next year, I still won't remember everything, but I'll know when and where to look. Remember also that the Red Book advice is in many instances a set of consensus opinions that are subject to author bias, even with extensive review and editing. Nothing is etched in stone, and individual patient circumstances may require deviation from general recommendations.
In the meantime, let's look at what's been going on in pediatric infectious diseases recently; this isn't in the Red Book.
A New Look CDC Website
Our friends at CDC announced a new look to their website with a focus on reducing clutter and making access easier. After my first series of run-throughs, I think they are well on their way to that goal. It's worth your while to view their 2-minute YouTube video describing the changes.
Bird Flu News
Still no reason to increase fears of the next human pandemic, but plenty going on. The US Department of Agriculture (they should talk to their CDC colleagues about reducing website clutter and improving navigation!) updated beef safety with some new studies. First, USDA tested ground beef samples from stores in states known to have influenza A H5N1 present in cattle; all were negative by PCR, although they don't mention how many samples were tested. Second, they performed studies on cooking ground beef spiked with Highly Pathogenic Avian Influenza "surrogate" virus (they don't specify details or numbers). Cooking the burgers to medium (145 F) or well done (160 F) eliminated all live virus. Rare (120 F) cooking "substantially inactivated" the virus, whatever that means. I'm looking forward to results of another ongoing study of PCR testing of muscle samples from cows who were culled due to "systemic pathologies" which should go a long way in helping understand if there is any reasonable risk of transmission of H5N1 in raw beef.
Meanwhile, in the latest update there have been no new state detections in domestic livestock since April 24. Bird infections remain a major problem as judged from USDA's main avian influenza website.
FDA provided a little more detailed information than did USDA. They found no viable virus in 297 pasteurized dairy products tested and confirmed by egg inoculation studies which should be highly sensitive.
Things are improving, but more proactive testing, especially of asymptomatic wild and domestic animals and high-risk humans such as poultry and dairy workers, is needed to stay ahead of any epidemic trends.
MMWR Trifecta
I'm not a big horse-racing fan, though I did watch the Preakness this weekend. This week's (May 16) MMWR hit a trifecta for me in that 3 topics are worth mentioning, so here's a quick look.
Measles: We have a detailed report of the outbreak associated with the migrant shelter in Chicago, spread over February through April 2024. Here's the quick overview:
The key take-home points: 1) Most of the 57 cases occurred in unvaccinated individuals; 2) active case-finding and a mass vaccination campaign (882 residents were vaccinated) likely averted a larger disaster.
I wish we had similar reporting from the Florida public school outbreak, apparently managed very differently but we know nothing about what was done. I can still find only a March 8 update that sounds mostly like a political statement.
Clade I Mpox: This clade I outbreak continues in the Democratic Republic of Congo and, compared to the clade II strain that caused the global outbreak in 2022, this clade I seems more virulent, with higher morbidity and mortality than seen with clade II (this was known prior to this outbreak). Again, here's the big picture:
While the numbers appear to be trending downward in the latter dates on this graph, this could be due to delays in reporting.
Age distributions are alarming for pediatric healthcare providers though clearly are influenced by social factors present in the DRC and might not apply to any US cases if we do see global spread.
The Jynneos mpox vaccine is effective against both clades, and high-risk individuals in the US should be vaccinated. The newly revamped CDC mpox site is a good example of how they've improved the look and ease of navigation. Providers should access this again to be sure they have offered vaccine to those at risk.
Polio: This was an update on progress towards polio eradication and is a good news/bad news report. The good news is that wild-type polio infections appear to be decreasing over the period January 2022 to December 2023. Wild type polioviruses types 2 and 3 (WPV2 and WPV3) have been eradicated, and only WPV1 continues to circulate but just in Afghanistan and Pakistan. In 2023 there were only 12 cases of WPV1 identified, compared to 22 in 2022, a decrease even with more extensive sewage screening in 2023. The bad news is that circulating vaccine-derived polio (cVDPV) cases, from live polio vaccine, continues to be a problem. The number of cases decreased (881 in 2022 to 524 in 2023) but the number of countries affected increased from 24 to 32. The vast majority of these are cVDPV1 and cVDPV2. WHO has newer and more effective vaccination strategies to eliminate both wild and vaccine-derived strain infections, but implementation is difficult.
Books - Red and Other Colors
Regular readers of this blog know that I'm an avid reader. I'm not an avid book collector, however. I try to keep a relatively static number of books in the house, requiring donating old books to my neighborhood public library's used bookstore as I acquire new ones (my last trip to a used bookstore resulted in 11 additions to my sagging bookshelves). However, I'm now reminded that I have 3 collections that I don't recycle from my shelves.
First is the Red Book. I own all editions dating back to 1961, the 13th edition, plus the 6th edition of 1944. I've been unable to find the remaining 11 editions, probably because I'm not as adept at used bookstore searches as I am at PubMed searches. I'll keep trying. Three pediatric infectious diseases giants, Drs. Larry Pickering, Georges Peter, and Stan Shulman, wrote a nice review of Red Book history in 2013.
My other 2 non-recyclable book collections are very different. One is the Audrey/Maturin series of nautical novels by Patrick O'Brian. I also own several of his lesser works. I'm not sure why I hang on to all of those; perhaps it's because my initial attempt at reading one was quickly abandoned due to boredom. Years later I picked it up again and was hooked. My other collector fascination is the Parker noir series by Richard Stark, a pseudonym of Donald Westlake. I lack many in the series which I could easily buy as newly issued printings, but I prefer to prowl used bookstores for older copies. I haven't happened upon an old one in years, but hope springs eternal.
Well, not really horror stories, but it was a slow week for epidemics that allowed me to finish two somewhat disturbing pieces of literature. First, the news.
I'm pleased to report nothing particularly new on the measles front, so I won't bother with the recitation of statistics and graphs. Based on the measles incubation period, it appears we are out of the woods from the Chicago clusters thanks to excellent public health interventions. The Florida school issue hasn't surfaced again though we are still lacking accurate descriptions of how it was managed - did un-immunized children isolate at home, were catch-up immunizations administered?
A Few Covid Updates
This past week the World Health Organization Technical Advisory Group on COVID-19 Vaccine Composition (TAG-CO-VAC if you're attracted to cumbersome acronyms) advised use of a monovalent JN.1 variant vaccine for the next iteration. Although the WHO TAG-CO-VAC doesn't make official recommendations for the US, none of these discussions occur in a vacuum and I expect the FDA VRBPAC to come to the same conclusion when they meet on the subject on May 16. The CDC/ACIP likely will rule on this in late June, in time for potential fall booster recommendations.
Here's the latest family tree in the US showing the.relationships of the currently circulating variants.
Also noteworthy is a change in hospital covid reporting. As of May 1, hospitals no longer are required to report covid hospitalizations. Although efforts are underway to go back to mandatory reporting, for now all hospital reporting is voluntary which will likely mean no reporting for many institutions. So, don't try to compare future covid hospitalization rates to prior data. It would be another apples and oranges comparison.
Lessons From Quality Improvement
This month's issue of Pediatrics contained some QI articles. They are worthwhile reading for the QI aspects, but I think many front-line pediatric healthcare providers might want to compare their own practices to the standards used in two of the studies concerning infectious diseases.
The first of the studies involved standards for management of well-appearing febrile infants ages 8 to 60 days in emergency departments. Parenthetically, I'm in awe of the authors for pulling off a multi-institutional research study in the midst of the pandemic. I barely had time to breath during some of those months.
The authors looked at multiple outcomes, and I won't go into the actual QI processes themselves. Here are the primary measures they sought to improve (remember these are all well-appearing infants):
90% of infants 29–60 d with normal inflammatory markers (and either a negative UA or a positive UA) DO NOT have CSF obtained
90% of infants 29–60 d with normal inflammatory markers and negative UA discharged from the ED
90% of infants 29–60 d with normal inflammatory markers and negative UA DO NOT receive antibiotics
90% of infants 8–60 d with negative cultures have appropriate discharge from the hospital within 36 h from the time blood cultures were received by the laboratory
How does your local ED or practice compare?
The second article also was hospital-focused and carried out during pandemic peaks. It dealt with minimizing unnecessary antibiotic use in common pediatric infections for children above 60 days of age. Again, many outcomes were examined, but think about these in your own practice:
Antibiotic duration for community-acquired pneumonia < 10 days
Antibiotic duration for UTI < 10 days
Antibiotic duration for skin and soft tissue infections < 5 days
The above durations for CAP and UTI probably are too long. It would be difficult to justify therapy beyond 7 days for these entities assuming good clinical response, and courses as short as 5 days have been suggested.
There's a lot more to these studies that I haven't mentioned. Please look at them if you manage these types of patients in your practice.
Of Cows and Cats
Bird flu, primarily influenza A H5N1, continues to surprise us. Let me state up front, however, there is no reason to be overly concerned about consumption of pasteurized dairy products or getting rid of your pet cat. People who ingest unpasteurized dairy or have close contact with cows or chickens (including those backyard coops) need to be cautious.
Genetic testing of dairy cow milk samples and of 2 cats who died at the dairy farm strongly suggests transmission of influenza A H5N1 from cows to cats. The cats had ingested unpasteurized milk at the farm. The cows were only mildly ill, but the cats had severe neurologic symptoms due to the virus. This report concerns only a few animals but at the least suggests that humans could be at risk for infection from unpasteurized dairy products.
We still have only one known human infection related to dairy cows in the US, but now we have more details about that case. As reported earlier, this dairy farm worker had mild symptoms consisting of pain and redness of the right eye. Especially given the perhaps mild and atypical presentation of influenza in this instance, more testing of asymptomatic dairy workers and other high risk individuals is needed.
I had mentioned in previous posts I'm trying to monitor USDA updates on this situation, but so far most have just clogged my inbox with irrelevant notices. I did receive one relevant alert that at least told me someone is watching out for us. Due to concerns about bird flu in the Chiba prefecture in Japan, imports of live birds as well as bird products and byproducts are prohibited. In case you are thinking about bringing back some bird souvenirs from Chiba, please be aware:
"Processed avian products and byproducts, including eggs and egg products, for personal use originating from or transiting a restricted prefecture and entering in passenger baggage must:
have a thoroughly cooked appearance; or
be shelf-stable as a result of APHIS-approved packaging and cooking (i.e., packaged in a hermetically sealed container and cooked by a commercial method after such packing to produce an article that is shelf stable without refrigeration); or
be accompanied by an APHIS import permit and/or government certification confirming that the products or byproducts were treated in accordance with APHIS requirements.
Unprocessed avian products and byproducts for personal use or in passenger baggage originating from or transiting a restricted prefecture will not be permitted to enter the United States. This includes hunter harvested, non-fully finished avian trophies and meat."
Reliable information on bird flu is increasing. It seems very likely that pasteurization effectively inactivates live H5N1 from dairy products and that these influenza strains remain susceptible to commonly available antiviral agents used for influenza. But, I still have questions:
What is the range of symptoms of avian flu infection in a wide range of animals, including humans?
How common is asymptomatic infection in various species?
What is the specificity and sensitivity of commonly-used influenza detection methods for influenza A H5N1?
For now, even though we are beyond our winter flu season, anyone with flu-like illness should be tested for influenza and also asked about exposure risks involving domestic or wild animals or ingestion of unpasteurized dairy products. Look to the CDC website for guidance.
My Disturbing Week
My wife abandoned reading Ian McEwan's latest novel, Lessons, due to its unsettling content in its early pages. Nonetheless, I decided to slog through this nearly 500-page tome and found I couldn't put it down. It was truly disturbing, including depictions of abuse of the young male protagonist that were hard to read. Ultimately, though, I found the novel very thought-provoking in spite of the fact that the protagonist wasn't very likable and seemed to respond passively to much of his life events. These events were shaped by a series of historical occurrences that also were meaningful to me: World War II (before my time, but still significant) the Cuban missile crisis in the 1960s, the fall of the Berlin wall, the September 11 attack, and more recently the January 6 attack, among others.
About a week ago I happened to watch Apocalypse Now Redux, the longer version of the 1979 movie about the Vietnam War which itself was a take on Joseph Conrad's Heart of Darkness. The longer movie version added more uncomfortable scenes to the already unsettling original. As a boy I had read at least 3 of Conrad's novels plus maybe a few short stories, but never Heart of Darkness. It's really a novella, just under 150 pages, and I felt compelled to read it this week. I loved it, as I do most of Contrad's works. More than that, I was astounded at how deftly the novella was transplanted from the late 19th century into late 1960s Vietnam. How did it not win the academy award for best adapted screenplay? (That was Kramer vs. Kramer.) I found myself waiting to see if the 19th century Kurtz would have the same *final utterance as in the movie version. You'll need to read the book to find out!
My Respite Week
Given the slow times in infectious diseases (now I've jinxed myself) and a busy week of other activities in front of me, I'm planning to skip a Sunday post for Mother's Day. Barring any major events, I'll see you next on May 19.
Even though Maryland wasn't in the full eclipse path, I miraculously located my eclipse glasses and enjoyed Monday's event. It easily overshadowed last week's relatively quiet collection of infections.
Newer Covid Publications
CDC gave us more reassurance that cardiac events associated with covid vaccination are mild. For the period June 2021 - December 2022, investigators looked at Oregon death certificate data in adolescents and young adults (16 - 30 year-olds). They found 40 deaths, 3 of which occurred < 100 days following receipt of covid vaccine, a time period when vaccine-associated myocarditis/pericarditis occurs. Of those 3, 2 individuals had underlying disease (one had mitral stenosis associated with chronic respiratory failure, the other congestive heart failure due to hypertension, with comorbidities of morbid obesity, type 2 diabetes, and obstructive sleep apnea). The other person died of "undetermined natural cause" 45 days after vaccination; toxicology results showed aripiprazole, ritalinic acid, and trazodone, presumably medications the individual was receiving but apparently not definitively explaining a cause for death. To most scientists this is further good news, but I'm sure anti-vaxxers will somehow spin this as a negative. Below is the big picture:
German investigators reported success of a program using pooled SARS-CoV-2 PCR testing to allow children to remain in day care versus quarantining after covid exposure, which they termed a "test-to-stay" approach.
The investigators estimated that. over a 30-week period, they avoided between 7 and 20 days of quarantine per eligible child. The study was performed from March 2021 to April 2022, at a different state of immunity and variants than we are experiencing today but still helpful to strategize when we hit the next big outbreak.
More on Bird Flu/HPAI
Highly pathogenic avian influenza news has calmed down a bit, but the viruses are still out there. We are up to 21 dairy herds with outbreaks according to USDA:
As of April 10, CDC reports widespread detections in wild birds with sporadic outbreaks in poultry flocks, sporadic infections in mammals, and still just the 2 human infections.
Measles
Not as many new cases now, with Illinois and Florida retaining the dubious distinction as leading all states this year. The national total stands at 121.
CDC reported that most US measles outbreaks from 1/1/20 through 3/28/24 were triggered by unvaccinated US residents returning from foreign travel. This is a good reminder for frontline clinicians to advise people planning foreign travel this summer to ensure their families have not only up-to-date immunizations but also early measles immunization for infants and toddlers who otherwise have not received 2 doses of MMR.
I also happened upon a link for assessing measles outbreak risk in US communities. I resisted the temptation to copy the entire page here, please check out the link. Here's a few highlights:
So, about 29% of US communities are at risk for small or medium outbreaks, with 1% at risk for a large outbreak. Even within communities with the same vaccination coverage, outbreak risk can vary if they have pockets of unvaccinated people.
And a look at outbreak modeling risks for measles outbreaks after one measles case is introduced in a school, according to vaccine coverage rates. (Note these numbers apply for situations where no post-exposure preventive measures are instituted. Risks go down if established interventions are applied.)
Here's the latest (2022-23) geographic measles vaccine coverage data.
Fingers crossed for measles to continue to slow down, though I'm predicting another blip around travel season.
