omicron variant – Page 2 – Pediatric Infection Connection

Backtracking

Bud WiedermannJune 16, 2024June 16, 2024Leave a comment

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!

Belated Eloquence of the Inarticulate

Bud WiedermannJune 9, 2024June 9, 2024Leave a comment

The title above is one of several great turns of phrase in the book I just finished reading, Edith Wharton's Age of Innocence. It refers to an episode where the protagonist was at a loss for words during a poignant encounter and presumably only later thought of something better to have said. I've been there.

Next Round for Covid Vaccine

The FDA's Vaccine and Related Biological Products Advisory Committee finally had their meeting last week; it had been postponed to give a little more time to see which way the new SARS-CoV-2 variants were headed. I was able to listen in on most of the meeting and have reviewed all the documents. The vote was unanimous to choose a monovalent JN.1-based vaccine for the next iteration, no surprise and in agreement with the recent WHO decision I discussed recently. (For those interested, there is quite a bit of international collaboration on these types of decisions. See the ICMRA posting about covid vaccines.) Still, there were some interesting updates on covid in general. I'll try to distill this down into the main takeaways.

The Latest on Epidemiology (from Thornburg FDA presentation)

Current circulation of SARS-CoV-2 is relatively low. Although our reporting is not as reliable these days, looking just at percentage of positive covid tests in orange you can see we are in a lull now, though perhaps with a hint of an uptick. This is pretty similar to last summer when we saw a bit of a surge in summer into fall and winter. SARS-CoV-2 still has not come around to a winter seasonality seen with other coronaviruses of with influenza, making predictions for surges and vaccine composition very tough.

JN.1 lineages replaced XBB.1.5 lineages during winter 2023-2024. I like the depiction below because it's looking at normalized numbers of positive tests rather than a percentage of positive tests due to different variants. This gives a better appreciation of numbers of cases and shows that we are still talking about relatively low numbers compared to 2022.

Here's a closeup of the most recent part of the above slide showing that KP.2-like, KP.3, and other JN.1 derivatives are starting to take over, though still all at very low numbers.

The recent subvariants have very few differences from other JN.1-derived strains and antigenically are very similar. This has important meaning for vaccine choice - should it be the original JN.1 variant or one of these newer KP.2 or KP.3 type subvariants, currently at extremely low numbers? Look at the last 2 rows in the table below, showing that these newer subvariants have very few mutation differences from the earlier JN.1-like variants.

In a totally new and as yet unpublished CDC analysis, severity of JN.1 infections does not appear to be worse than earlier lineages. The trend was towards milder illness, though not statistically significantly different. Note these numbers are just for adults.

Vaccine Effectiveness in Children (from Link-Gelles FDA presentation)

This it tough to estimate because children generally have milder disease, plus so few children are vaccinated. Adult data is pretty favorable for VE; SGT failure is a faster method of testing and correlates will with JN.1 lineage strains. 2023-2024 VE drops a little with these strains compared to effectiveness against XBB lineage strains.

On the pediatric side, it's important to remember that the vast majority of US children have been infected with SARS-CoV-2 at some time in their lives - this has been apparent since late 2022.

So, it's important to determine any VE now in light of prior infection and vaccination. We can't rely on older estimates. Here's the best and latest estimates for VE in children who received vaccine in the past year. Confidence intervals are relatively wide, reflecting the small numbers able to be studied, but do show benefit in prevention of ED or urgent care use. VE wanes with time after vaccination as it does with all age groups, but there is clear benefit for covid vaccination of children.

David Wentworth, representing WHO, delivered a wonderful explanation of the complexities in choosing among current subvariants for vaccine inclusion. He had this great quote: "... antigenic evolution just speeds up waning immunity." The variant evolution we're seeing now is parallel, i.e. lots of different subvariants evolving on their own, in parallel, rather than one subvariant evolving into another, and then into another, etc. Parallel evolution is what XBB lineages did previously, and we're seeing it now in the JN.1 groups. The slide below demonstrates this process with a timeline on the X axis.

The dilemma in choosing composition of the next vaccine is that no one knows which way the very new subvariants will evolve in terms of antigenic similarity to earlier JN.1 strains. Currently, KP.2, KP.3, and JN.1.23 are within what is thought to be close proximity to JN.1 in terms of antigenic similarity and therefore a vaccine based on any of those likely will have cross-reactivity with one another, enough to provide protection. However, as illustrated by the arrows, it just isn't known how the offspring of the newer subvariants will evolve - will it be farther away from JN.1 and each other, or will it remain relatively stable?

No one can predict what next fall's or winter's subvariants will look like. Once they appear, new lab testing would need to be done, ideally using human serum containing antibody to the newer strains, which Wentworth stated would take about a month to produce. So, it's not something that can be turned around quickly.

Also, it bears mentioning that virtually all of the immunity studies involve neutralizing antibody. Antibody does correlate well with VE, but T-cell immunity also is important. We don't see as much data about this arm of the immune system because the studies are more difficult.

All 3 US vaccine manufacturers, Moderna, Pfizer, and Novavax, presented their new data at the meeting. They are developing and testing new vaccines "at risk," meaning the companies are making vaccines without funding currently, risking their own research and development dollars, hoping whatever they are working on will be recommended for the next covid vaccine rounds and allow them to recoup their investment. Moderna and Pfizer have both developed JN.1- and KP.2-based mRNA vaccines. Novavax, the adjuvanted protein-based vaccine, only developed a JN.1-based vaccine. The protein vaccine takes much longer to construct than do mRNA vaccines, about 6 months to get good data in all. So, if a KP.2 or other vaccine were recommended, Novavax would need to start over and wouldn't be ready until about December.

I don't usually like to use pharma slides to illustrate points, but this one from Pfizer isn't biased in favor of their product and I think nicely shows the current situation, including how closely related the newer subvariants are to JN.1.

In the discussion after the vote to have a monovalent JN.1-based vaccine, which could mean one based on KP.2, the majority of the group felt that using the JN.1 variant rather than KP.2 or another subvariant was the best route, both to allow Novavax to be ready this fall but also not to take a chance that fall and winter predominant subvariants might be more antigenically removed from KP.2 antigenically. All in all I felt this was the right choice, though I probably wouldn't have let Novavax's problems affect the decision; very few US residents have received Novavax in the past, though it is nice to have an alternative to mRNA vaccines available.

On June 7 the FDA formally recommended sticking with the JN.1 strain for this next vaccine round. Next step with be the CDC's Advisory Council on Immunization Practices meeting the end of this month, where the official seal of approval will be issued. I'm sure Moderna, Pfizer, and Novavax already are ramping up production.

NASEM Long Covid Report Available

Long covid remains a quagmire, lots of different symptoms, many of which are vague, and still no definite light shed on diagnosis and treatment of what is likely a heterogenous group of conditions requiring different approaches. The National Academies of Science, Engineering, and Medicine published their full report, available free online. I haven't gotten through all of it, it's pretty long, but it is of interest to those practitioners who see these patients. Most of the evidence is from adults, but it appears that pediatric patients tend to have a better prognosis, especially if improvements are occurring in the first year after onset. Note that a positive covid test is not required for diagnosis testing may not have been done at the time of the triggering infection and antigen or PCR tests will have reverted to negative by the time a long covid diagnosis is considered.

Doxycycline for Post-Exposure Prophylaxis of STIs

The official guidelines appeared this past week, although the gist of the recommendations had been floated previously. Particularly high risk groups are gay, bisexual, and other men who have sex with men and transgender women. The summary is very helpful for practitioners who may want to print out and post Box 1 and Box 2 in their workspaces. Note that the recommendations apply just to those high risk groups.

Summer Bugs!

Bugs in the sense of both insects and microbes. We now have more details about a new rickettsial agent, termed species C6269, that caused a Rocky Mountain Spotted Fever-like illness in 2 individuals in northern California last summer. Both had severe disease, were hospitalized and treated with doxycycline, and survived. As always, keep RMSF and other tick-borne diseases in mind during our warm months.

Speaking of bugs, our dog came down with a skin abscess, expertly debrided by her veterinarian. She is now enjoying chewable amoxicillin/clavulanate but is less thrilled with her "cone of shame." The vet had another bug concern, however. She didn't want the dog to spend much time outside - apparently it is also maggot season, and they love open dog wounds. The vet doesn't know I'm an ID doctor, and I was trying to come up with some clever comment on maggots but failed at that moment - belated eloquence of the inarticulate!

Courtesy of Wikipedia. Hope you aren't eating as you read this.

Less Illness, More Chatter 2

Bud WiedermannMay 26, 2024May 26, 20242 Comments

We've had a slow week of infectious diseases events, but that hasn't slowed down the chatter and noise. I've tried to distill out the more important topics this week.

The Covid Front

Even though US tracking systems have been greatly dismantled in many states, I can still safely say we are in a lull. Naturally, thoughts turn to predicting the next surge and how to mitigate it.

I mentioned in my May 5 post that the FDA's Vaccines and Related Biological Products Advisory Committee meeting to decide on composition of the next iteration of covid vaccine would be held on May 16 and likely would make the same decision as the WHO already has, using the JN.1 variant. However, they suddenly postponed this meeting to June 5. FDA didn't offer an explanation for the postponement, but the last-minute change leads me to suspect that they wanted a little more time to think about newer variants with possible significant differences in immune-escape properties. Here's a deeper dive into that.

As you can see in this latest CDC variant report, the dark purple JN.1 proportion is decreasing, with KP.1 and KP.2 starting to expand. Both of those are in the JN. 1 lineage:

All of the JN and KP variants are informally called FLiRT variants, an easier shorthand than trying to remember all the letters and numbers. It stands for amino acid substitutions, in this case phenylalanine (F) substituted for leucine (L) in the 456 position (F456L) and arginine (R) to threonine (T) in the 346 position (R346T) in the spike protein genomic code. These 2 mutations are in antibody binding sites that neutralize the virus, and the mutations make SARS-CoV-2 less vulnerable to vaccine- and infection-acquired antibodies. A JN.1-derived vaccine likely would offer some protection, but perhaps by the June meeting we'll know a bit more about all of this. If they do recommend using KP.2 instead of JN.1 for example, I don't think there would be a significant delay in mRNA vaccine production by Pfizer and Moderna, but it might cause problems for other vaccine platforms such as the one used by Novavax, the other approved vaccine in the US which is an adjuvanted protein subunit vaccine. I'll be watching as much of the June 5 meeting as I can.

HPAI

Now we have a grand total of 2 people in the US infected this year with Highly Pathogenic Avian Influenza, along with a lot of cattle and other animals; a recent MMWR provides details. The new, improved CDC website has lots of helpful links. The second case, in Michigan, was similar to the first human case of A H5N1 infection in Texas - very mild illness with conjunctivitis as the primary symptom. This strikes me as very unusual for evolving epidemics in that usually the more severe cases are identified first because they are more likely to come to medical attention. Both of these cases were identified through surveillance of dairy workers which suggests to me that currently HPAI in humans is a very mild infection, possibly with high rates of asymptomatic infection. This is a good thing generally, but also problematic for tracking infection rates. The MMWR reports only 350 exposed dairy workers are being followed, a very small number. Ideally we'd have more tracking of cattle and dairy workers, regardless of illness or exposure to infected animals. Getting cooperation from dairy farms will be difficult, we're talking about livelihoods in an industry where a shutdown for a cow outbreak could send someone into bankruptcy.

I'm watching multiple feeds to keep up with all of this. A report in NEJM last week was encouraging - heat inactivation of spiked milk samples significantly lowered infectivity in mice fed the milk.

Also in the good news department, USDA reported preliminary findings on HPAI detection in muscle tissue of culled dairy cows. 95 of 96 samples tested so far were negative by PCR. Note that these were condemned animals, none of the meat entered the food supply.

On the somewhat negative side, more cattle herds have been hit with the virus, according to USDA.

Poultry outbreaks also continue with Minnesota registering more detections last week. Note that backyard flocks are not immune to HPAI.

On a slightly related topic, I was disappointed but not surprised to learn that the World Health Assembly, the decision body for the WHO, removed a pandemic preparedness treaty that was to be discussed at their meeting starting May 27. It appears that political considerations caused the cancellation; much misinformation is circulating, especially in the US. The treaty would help countries design programs for pandemic preparedness and in no way allows the WHO to control countries' own public health programs as claimed by some sources.

Potpourri

A scattering of reports might be interesting for readers. First, beware of undercooked bear meat. Six out of eight people who consumed undercooked, previously frozen black bear meat developed trichinellosis. Freezing doesn't kill Trichinella parasites. Beware the (undercooked) bear.

CDC released a Health Advisory Network alert for meningococcal disease in Saudi Arabia, although this is pretty much routine for this time of year during religious pilgrimage season. Travelers to the region should be immunized for meningococcal disease, which is more easily transmitted in the crowded situations during Islamic pilgrimages to Mecca.

Speaking of Noise

I'm pretty sure I've never mentioned this in the blog, probably because I'm so embarrassed, but I'm a 2-time harmonica school dropout. This last exit was due to a combination of my inability to master bending notes on the diatonic harmonica and the fact that my dog runs away from me every time when she hears my mellifluous tones. I've now solved the second problem by clearing a practice space in my trash-heap of a basement where the dog can't hear me, but bending will still be a challenge. It's a technique to hit notes that are in between standard notes; there are maybe hundreds of online instruction sites for how to form your mouth to do this, but basically it's just trial and error and takes several months for most people.

Graphic courtesy of Luke.

Maybe by announcing my intentions I'll be shamed into pulling it together this time and can return to harmonica school. I can't promise to report on my progress, especially if I have none!

Obstinacy or Ignorance or Fear

Bud WiedermannMarch 24, 2024March 24, 2024Leave a comment

Those words written by a famous children's author in 1988 remain relevant today; details to follow after a few mentions of other pediatric infectious disease news from the past week.

Covid Serology Update

The Infectious Disease Society of American updated their guidelines for use of covid serology testing. It is the 4th update since the pandemic began, but there isn't much new here. Currently over 95% of the US population has evidence of immunity either from natural infection, vaccination, or both. Serologic testing of individuals mostly is discouraged because it won't provide any useful clinical information to manage an individual's situation. About the only use might be to check immunity in immunocompromised individuals to help decide if immunotherapy could be warranted for prophylaxis or for treatment of active infection.

Covid in Young Infants

Early in the pandemic, most very young infants diagnosed with SARS-CoV-2 infection were hospitalized. This was due to a combination of the usual practice for febrile infants less than 1 month of age as well as the uncertainty of infection outcomes in this age group. I recall from my clinical experiences that it appeared that most young infants actually did well, though there were exceptions. Finally we have a study that gives us some more detailed data about young infants early in the pandemic. It is a secondary analysis of a prospective global study that recruited children presenting to pediatric emergency departments with illness and tested for covid. The study design allows for much more detail (and presumably more validity) than the other designs such as review of administrative data. The study (actually 2 studies combined) enrolled between March 2020 and February 2022. They ended up with 432 children testing positive for covid to compare with 616 testing negative. Clinical outcomes were generally more severe in the SARS-CoV-2-negative infants:

So, at least early in the pandemic, young infants with SARS-CoV-2 infection fared pretty well.

A Colorful Variant Update

Nothing new about this, but I admit to a strange attraction to colorful covid variant charts. I thought it was interesting to look back to see how the JN.1 variant progressed in the US.

The JN.1 shade of purple has been called "indigo purple" (hex #660999).

Varicella Misdiagnosis

A new CDC report suggests clinicians aren't too skilled in diagnosing varicella infections, perhaps because it is now much less common due to effective vaccination. The Minnesota Department of Health looked at suspected varicella cases from 2016 to 2023, a time when they implemented a new system for processing PCR testing of lesions. Of 208 suspected varicella cases, only 45% had positive tests; in vaccinated patients, the number dropped to 22%. They attributed this to unreliability of clinical diagnosis of varicella, especially in vaccinated patients, but I suspect other factors (improper specimen collection technique, testing unlikely varicella patients "just to be sure") may be contributory as well. Anecdotally I've certainly noticed how difficult the diagnosis varicella-zoster virus infection can be for younger clinicians who don't have the experience of seeing multiple cases in the pre-vaccine era.

Speaking of Misdiagnosis ...

I'm in my broken record mode again here. In case you've been hibernating or torporing, we're in the midst of a global measles surge. I read with alarm of a measles vaccine shortage in Canada. There are no signs of a similar shortage in the US; you can always check on US vaccine shortages at this CDC site. With spring break upon us now, and summer travels coming up, all of us need to brush up on measles diagnosis. Thankfully we have a lot of help.

Last Sunday, the CDC issued a Health Alert Network post with a number of useful links. The American Academy of Pediatrics provides a one-pager with great advice as well as a 5-minute video. Another source I've found very useful for years is from a now out-of-print textbook, Krugman's Infectious Diseases of Children. When I discovered libraries no longer carried it, I tracked down a used copy of the 10th edition (1998) released by a university library and have made continued good use of their black and white diagrams. Here's the clinical progression of illness, the key highlight here is the prodrome of a few days before the rash appears. This is very helpful in suspecting a measles diagnosis because the prolonged prodrome is very unusual in pediatric infectious exanthems.

Also useful is the development and distribution of the rash:

I failed to find a current global measles map so return to the CDC website to at least give a current view of US measles cases. For this calendar year we are now up to 64 cases spread over 17 jurisdictions.

Many clinicians may not remember that, though the first measles vaccine was approved for use in the US in 1961, it wasn't until 30 years later that a second dose was recommended. That was spurred by cases in the late 1980s appearing in vaccinated school children, the first major sign that a single dose wasn't sufficient to prevent outbreaks. That second dose was first recommended for 11-12 year olds by the AAP, subsequently dropped to the 4-6 year age group in 1997 to come into agreement with the CDC. Importantly, the interval between the 2 doses can be as short as 28 days for MMR and 90 days for MMRV vaccines, and early vaccination down to 6 months of age is indicated in special circumstances, such as for children who will be traveling internationally. Frontline pediatric providers need to be proactive in alerting parents planning international travel to ensure that their children ages 6 months and older are protected. Scroll down to the Special Situations section on the CDC immunization schedule notes.

Roald Dahl

I learned just recently that this famed children's book author lost a daughter to measles in 1962. He wrote 25 years later, "Olivia, my eldest daughter, caught measles when she was seven years old. As the illness took its usual course I can remember reading to her often in bed and not feeling particularly alarmed about it. Then one morning, when she was well on the road to recovery, I was sitting on her bed showing her how to fashion little animals out of coloured pipe-cleaners, and when it came to her turn to make one herself, I noticed that her fingers and her mind were not working together and she couldn’t do anything. 'Are you feeling all right?' I asked her. 'I feel all sleepy,' she said. In an hour, she was unconscious. In twelve hours she was dead.”

She had developed measles encephalitis. He wrote this in the late 1980s to encourage parents in the United Kingdom to accept a new MMR vaccine for their children (monovalent measles vaccine had been introduced in 1968 in the UK). He also wrote, “In my opinion parents who now refuse to have their children immunised are putting the lives of those children at risk. In America, where measles immunisation is compulsory, measles, like smallpox, has been virtually wiped out. Here in Britain, because so many parents refuse, either out of obstinacy or ignorance or fear, to allow their children to be immunised, we still have a hundred thousand cases of measles every year.”

Much has been written about Dahl's dark side (e.g. "an equal-opportunity bigot"), but I give him credit for trying to help children and their parents avoid the misfortune he and his family experienced.

Measles in My Backyard

Bud WiedermannFebruary 4, 2024February 4, 2024Leave a comment

Well, not exactly, and directionally it's more like my front yard. On February 1 the Maryland Department of Health issued a press release of a measles case in a recent international traveler who resides in my Maryland county, listing an apartment complex with my same home zip code as a site of potential exposure. Details are lacking, and I do note the DOH still hasn't sent a notice to Maryland licensed physicians. Keeping my fingers crossed there are no secondary cases.

Last Summer's Vibrio vulnificus Flurry

CDC reported on last summer's burst of V. vulnificus infections across 3 states, a total of 11 severe cases occurring during heat waves in residents of Connecticut, New York, and North Carolina. Median age was 70, and 5 people died. Of the 10 with available information, all had at least 1 underlying risk factor for severe Vibrio infection, including diabetes (3), cancer (3), heart disease (3), history of alcoholism (3), and hematologic disease (2). While the clusters can't be blamed definitely on the heat, Vibrio growth is augmented in warm water; we may see an increase in Vibrio infections associated with climate change.

An impaired reticuloendothelial system (including liver disease from any cause) is a big risk factor; high risk individuals should be warned about avoiding contact with brackish water, salt water, and raw seafood (2 cases last summer had raw oysters as only known exposure).

Late Treatment for Congenital CMV

A new report from the Collaborative Antiviral Study Group reported on a phase 2 randomized, double-blind, placebo-controlled trial of 6 weeks of oral valganciclovir for infants 1 month to 3 years of age with congenital CMV infection and sensorineural hearing loss. Although the treatment group had much lower urine and salivary viral loads during treatment, there was no difference in hearing outcomes compared to the placebo group. Back to the drawing board.

Diphtheria in Africa

It looks like diphtheria is going to be a big problem for some time to come. WHO lists major diphtheria outbreaks in Nigeria (the most cases), Guinea, Niger, Mauritania, and South Africa. The cumulative total of suspected cases is 27,991 with 828 deaths. For those of you needing a little help with African geography, here's what it looks like:

So, this is not just clusters related geographically, but rather scattered throughout the continent. Cases were more prominent in the pediatric ages, and about a quarter of the cases were fully immunized. The numbers could be much higher given the difficulties in diagnosing diphtheria in resource-poor settings.

Bad E. coli in China

Although I'm never happy to hear about new virulent and resistant organisms, I was particularly unhappy about this news for a few reasons. First, it is a hypervirulent strain, apparently more likely to cause severe invasive infections. Second, it carries carbapenem resistance, often our last relatively safe resource in the antibiotic armamentarium for multiply resistant Gram negative bacteria. Worse is that 13% of these carbapenem-resistant organisms did not express a known carbapenem resistance gene, suggesting other perhaps new resistance mechanisms might be present. Lastly, these organisms caused a prolonged outbreak in a children's hospital.

You can see this outbreak occurred a few years ago, but I don't think we've heard the last of this.

WRIS

I'm looking forward to the week when I can retire a regular update on Winter Respiratory Infection Season. For now we have some encouragement but still too early to tell which way we're headed, especially with covid since our data sources are less reliable/predictive.

We seem to be over the hump with RSV season, still plenty out there but we tend not to see late rebounds with RSV.

Flu is a mixed bag depending on locale, but seems to be headed downward overall.

The covid wastewater report doesn't look too bad, either.

JN.1 is the predominant variant in most places now. I include a graph from the UK just because it's pretty.

We also have some other good news on the covid front: the fall vaccine seems to have high effectiveness (54%; 95% CI 46-60%) against development of symptomatic infection in immunocompetent adults. The study covered the time period September 2023 - January 2024 so is very recent and includes the time of JN.1 variant predominance.

Squirrel Wars 2.0

Speaking of my front yard, it is the new site of my war to keep squirrels away from my bird feeder, first mentioned in these pages on January 14. You recall that the capsaicin-laced safflower seeds, advertised as obnoxious to squirrels, turned out to be a delightful snack for those obnoxious rodents here. I tried to access research proven methods for preventing squirrels from eating all the bird food, but sadly there doesn't appear to be a trove of studies to guide me; in other words, no such thing as evidence-based squirrel medicine.

However, many sites mentioned trying to choose a site for a feeder that is beyond the reach of a typical squirrel's jumping prowess of 5 feet upward from the ground, 7 feet across, and 9 feet downward. After much thought, we selected a site in a large front yard tree. Armed with my long-suffering wife's long tree branch cutters and her assistance, 2 rickety ladders, slippery wire, packaging tape, and an autographed baseball from my youngest son's youth baseball team (circa 1990's, I was the official scorekeeper since I was too uncoordinated to be a coach), I succeeded in placing it in the perfect place with only minimal self-injury. Passersby seemed alternately amused and alarmed. If this works, I should get a MacArthur genius grant.

Tag: omicron variant