measles vaccine – Pediatric Infection Connection

Readers of past postings know I try to avoid politics in this blog. Today's post represents a complete failure to achieve that goal. I have followed RFK Jr.'s statements and writings about vaccines and public health for many years. His brand of pseudo-science is incomprehensible to me and anyone who understands biology and scientific methodology. His confirmation as HHS Secretary last week marks a sea change in the American health system; although he spouts some worthwhile targets to improve public health, in his new position he poses a grave public health threat for infectious diseases in particular. Regardless of any specific vaccine or other policies he might introduce, his mere confirmation as HHS Secretary may serve to further normalize anti-vax sentiment and likely will increase rates of vaccine refusal. Welcome to the new Dark Ages, though I doubt it will last several centuries like the last one. More on this later.

The Global Watch

A number of things to be aware of globally, though none immediately troublesome for the US.

Marburg Outbreak in Tanzania

This outbreak of a viral hemorrhagic fever disease (similar to Ebola) was declared about a month ago. Ten cases (2 confirmed, 8 suspected) have been identified, all fatal. Now, the 281 contacts of those 10 cases have passed the 21-day incubation period and remain well, very reassuring. However, WHO still rates the risk at the national level as high, given that the locale, Kangera, is a major regional transportation hub to other countries. Risk for global spread is still low.

Ebola (Sudan virus) Outbreak in Uganda

AfricaCDC reports that the vaccine trial is underway now in 7 of the 8 planned sites. Disease activity seems relatively stable, though the weekly reports tend to lag with last update posted from February 10.

PPE for VHF

With every viral hemorrhagic fever outbreak, healthcare providers comprise a prominent number of infected individuals. This occurred even in the US when 2 American nurse providers were infected during the 2014 importation from travelers. It's a good time to remember precautions to prevent VHF spread in healthcare settings, also a bit confusing since different guidelines apply according to whether the suspected patient is clinically stable or unstable. Front line providers need to contact their friendly local ID or infection control practitioner for help as soon as a suspected VHF case is encountered. Remember to obtain a good travel history.

mpox

In WHO's February 13 situation report, clade Ib mpox remains primarily in the DRC, Rwanda, and Uganda. MMWR just reported confirmation of a case of Ib infection in California from November 2024, in a traveler returning from east Africa. More on MMWR later.

Measles Again!

No surprise, but we have new outbreaks in the US, presumptively heavily related to cases in unvaccinated persons who were old enough to have received 2 doses of MMR vaccine.

A February 14 update from the Texas Department of State Health Services lists a total of 48 cases in the South Plains region, with age distribution of 13 cases in 0-4 year-olds, 29 in school-aged children (5-17 yo), 5 18 and older, and 1 with age unknown. Digging through the data from their spreadsheet links, MMR coverage in 2023-24 in the Seminole ISD (apparently the epicenter of the outbreak) is an appallingly low 82%. In Gaines County, home of 42 of the outbreak cases, the rate of "Conscientious Exemptions" for vaccine administration for children rose from 7.45% in 2013-14 to 17.62% in 2023-24. Even the earlier rate is super-high. Gaines County is the red box below.

The CDC measles page is updated only monthly, perhaps not frequently enough given the current situation. And, speaking of the CDC ...

Interesting Week Ahead for the CDC

I'll be watching closely this week. MMWR seems to be back, but with fewer topics per issue. I looked at the 2024 content, and only about 10% of the weekly publications had less than 4 topics. Both issues following the "publication pause" had only 2 articles each.

More telling, the Advisory Council on Immunization Practices is scheduled to meet on February 26-28. The draft agenda was released on January 19, and I'll be interested to see if the topics change. Currently on the schedule are votes on meningococcal, chikungunya, and influenza vaccines plus further discussion on maternal and pediatric RSV vaccines on Wednesday. These are not particularly high profile targets for the anti-vaccination lobby or for anti-DEI issues. However, part of the discussion process for vaccines at ACIP meetings has been an "Evidence to Recommendations" portion that normally includes a section on equity. I wonder whether this will change. Thursday's draft agenda includes perhaps more controversial subjects of HPV and mpox vaccines, due the relationship of these infections to spread via sexual contact in different high risk groups. Thursday's discussion also touches on pneumococcal and adult RSV vaccines, plus a 5-minute blurb on Lyme disease vaccination that I'm wondering about. The meeting wraps up Friday morning with discussions on covid (!) and CMV vaccines. I hope to attend much of the meetings and I'll report back next week.

This week's New England Journal of Medicine included a Perspective written by 3 former editors-in-chief of MMWR plus a former director for one of CDC's Centers. It was entitled "The Consequences of Silencing the 'Voice of CDC.'" Clearly the authors carry some implicit bias in favor of the CDC, but the article was enlightening. They repeated the reports I heard that the February 6 issue suppressed a discussion on H5N1 influenza (may have related to spread between cats and humans), which is concerning. I was interested to learn a bit of history: MMWR first appeared in 1961, during my lifetime but in a period when my interests fell more along the lines of Tinkertoys and butterflies. Currently I am one of 147,000 electronic subscribers to MMWR. CDC shares titles and brief summaries of reports with the Office of the Assistant Secretary for Public Affairs at HHS to alert them of content, but the authors were not aware of any time the reports had been altered or censored by the executive branch.

The authors went on to mention how rapid publication in MMWR helped public health management, citing the initial descriptions of what was eventually AIDS, outbreaks of foodborne illness related to hamburger contaminated with E. coli O157:H7, and anthrax related to intentional distribution of anthrax spores. I was a practicing pediatric ID physician during all of these outbreaks and still remember reading MMWR and changing my practice to account for new disease situations.

In addition to the evolving VHF situation in Africa mentioned previously, we need ongoing high-level surveillance for avian flu and for the large outbreak of tuberculosis in Kansas. With regard to the former, we did hear some information in MMWR this week: new serologic evidence of H5N1 infection in veterinarians providing care for cattle but with no known link to infected herds, suggesting more widespread cow infection than has been detected so far.

As an aside, since I do most of the grocery shopping in my household, I discovered the USDA has egg market reports. If you need some distraction from hand-wringing, you can track how many 30-dozen egg cases are moving around in your region each weekday!

WRIS

I'm thinking I don't need to tell any front line healthcare provider that influenza season is in full swing and is the one prominent player in our winter respiratory infection season at the moment.

More concerning is that illness severity is quite high.

Virtually all circulating strains are influenza A, and avian flu is not contributing to this with still just a handful of human cases detected in the US. Not too late to vaccinate.

My Test Grade Was 3

Please pardon my error last week in inviting readers to take the "How Ignorant Am I?" online quiz, not realizing it required subscription access. The quiz itself is based on a 1950 publication by statistician and weather forecaster Glenn W. Brier, updated in the Nature article you probably can't access. Briefly, the new quiz consists of 5 questions covering percentage of water in human body parts, timing of publication of genetic theories, planet size, number of atoms in common molecules, and melting points of precious metals; in short, scientifically based but nothing recently discovered. The kicker to the quiz is that it's not just whether you provide the correct answer, but that you quantify your confidence in the answer you provided. The scoring system is weighted such that failure (getting the wrong answer but thinking you are correct) is punished more severely than rewarding success (just getting the right answer). Here's the scoring interpretation: "If you ended up with a negative total, you did worse than a complete ignoramus who just answered 5 to every question" [5 indicates you had no idea which answer was correct, resulting in a score of zero if you answered 5 for all questions]. "People who actually know a lot, or are extremely lucky, get higher scores." (The highest possible score, getting all answers correct and being absolute certain of your answers, is 125.). So, my score of 3 isn't great, with a consolation prize that "Those with an awareness of their own doubts ... might end up with a small positive score." The main point of the quiz was " ... to train forecasters to be less over-confident, and have insight into their own thought processes." Applies to weather forecasters and possibly to healthcare providers as well!

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.

Tag: measles vaccine

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