E. coli O157:H7 – Pediatric Infection Connection

U.S. Representative Tip O'Neill popularized this phrase in the early 1980s, but perhaps it lost its meaning in later years. Has that changed? Infectious diseases, on the other hand, are most certainly not local.

Infectious Diseases Abroad

Any ripple in communicable infectious diseases in one locale inevitably affects others in far-away locations. Last week saw a number of ripples.

(Not) Measles in American Samoa

Yes, I'm aware that American is a US territory, but it certainly qualifies as far-away.

In 2023, health authorities in American Samoa went on a wild goose chase based on non-recommended testing practices of a suspected case, resulting in a large expenditure of time and money with no benefit. I'm not faulting Samoan practitioners, they had to deal with a lack of available testing resources in the setting of an island rocked by a deadly measles outbreak a few years ago; that outbreak had been fueled in part by prominent anti-vaccination proponents. This recent episode should serve to remind us of proper use of measles diagnostic testing which relies most prominently on use only for individuals who fulfill proper case definitions.

The above report was in last week's MMWR which also contained a WHO measles update. Here's a comparison of 2000 and 2023 measles cases and deaths (note North America is not included in these numbers.)

Severe Avian Influenza in Canada?

Last week Canadian officials confirmed that a critically ill teenager is infected with influenza A H5N1. The source is still unknown, and no close contacts are known to be infected. It's been very tough to get details about the patient's illness, but after going through a transcript of a British Columbia health official's briefing on November 12, it seems that the previously healthy child presented with typical H5N1 symptoms of conjunctivitis, cough, and fever, but then several days later had deterioration. That sequence of events, a sort of biphasic illness, is classic for secondary bacterial complications of influenza. Influenza virus infection of any type can be complicated by secondary bacterial processes, including sepsis and toxic shock syndrome, usually several days after initial flu symptoms begin. Canadian authorities haven't provided any more details, but I wouldn't be surprised if this is what's going on. I'm hoping it was recognized quickly and his healthcare team can return this person to normal health.

Along these lines, NASEM just issued a new publication detailing research priorities for avian influenza A H5N1 readiness. Some of this is already happening, and I hope funding priorities will continue to support planning.

Mpox Update

Last week WHO updated the status of the mpox outbreaks across Africa, a mixture of good news and bad news. Priorities are delivering vaccine to those at risk and implementing newer PCR testing for mpox just approved by the AfricaCDC. Also this past week we learned of the first mpox clade 1 case in the US, occurring in a traveler returning from Africa.

Number Needed to Vaccinate for Covid in the UK

I've mentioned in previous posts that the UK recommends many fewer groups for covid vaccination than we do in the US, primarily because of cost considerations. Last week the UK's Joint Commission on Vaccination and Immunization gave us a bit of a closer look at how those decisions are made with some NNV calculations. NNV (along with its cousin Number Needed to Treat for medication) are a good way to explain "bang for the buck." NNV simply refers to the number of individuals needed to vaccinate to prevent one additional case of the infection, compared to no vaccination. It depends on many variables including the rate of the disease and the number of susceptible individuals in the community and the vaccine effectiveness. Also, NNVs vary with the outcome of interest, such as infection versus hospitalization versus death. It's increasingly harder to calculate NNVs for covid vaccine because of asymptomatic infections and less widespread testing being performed.

The JCVI didn't give us NNVs for all age groups, but they did provide a close look at pregnant people and infants under 3 months of age, the latter group of course not eligible for vaccination and dependent on maternal immunity passed to them transplacentally. I had to dig into attachments to the reports, but here's the bottom line: NNV to prevent hospitalization of a pregnant person is "just under 2000" and "around 300,000" to prevent severe hospitalization. I couldn't find a definition of severe hospitalization but from the context it appears to be something more than overnight observation but less than ICU admission.

For infants < 3 months of age, NNVs (for maternal vaccination) were "under 500" for any hospitalization, "just over 13,000" for severe hospitalization, "almost 190,000" for ICU admission, and ranged from 380,000 to 1.5 million for mortality, the latter extremely hard to calculate due to rarity of the outcome. (But we're all thankful that it is rare.)

Just for comparison, NNV for flu vaccine to prevent 1 additional outpatient visit or 1additional hospitalization in children 6 - 59 months of age ranged from 12 - 42 and about 1000 - 7000, respectively, in one study.

Novavax Combination Covid-Flu Vaccine Study Allowed to Resume

I mention this item mostly to show how well our vaccine safety oversight is working. This study was paused when 1 phase 2 study participant developed what was initially diagnosed as motor neuropathy (with concern for Guillain-Barre syndrome) but then turned out to be amyotrophic lateral sclerosis, not an inflammatory disorder plausibly related to vaccination. This is one of many mechanisms for detecting evaluating rare events after vaccination. Novavax now can proceed with phase 3 studies.

E. coli O157:H7 Outbreak Numbers Grow ...

... but not related to ongoing infection, simply reflecting a delay in case reporting/verification. CDC and FDA report we are now up to 104 cases spread over 14 states. Of the 98 persons with more detailed information available, 34 were hospitalized and 4 developed hemolytic-uremic syndrome. "Of the 81 people interviewed, 80 (99%) report eating at McDonald's. Seventy-five people were able to remember specific menu items they ate at McDonald's. 63 of 75 people (84%) reported a menu item containing fresh slivered onions."

The case map strongly resembles the distribution map for the suspected onions which are now out of the food chain.

In the meantime, we have another E. coli O157:H7 outbreak, this time associated with carrots. [Correction added 11/18/24: this outbreak is due to E. coli O121, not O157:H7 as originally stated.]

I have a feeling I'm going to be washing my salad items more carefully for a while!

WRIS

The winter season still hasn't started, so I'm reduced to browsing the wastewater maps, all updated through November 14 and current through November 9. Here is maybe a look at things to come. First, here's covid:

Now flu (wastewater only tracks influenza A):

Last but not least, RSV:

I'm a Throwback

When I started practicing medicine, implicit in my professional obligations was the duty to do my best to treat anyone who presented to me, without regard to their backgrounds including race, gender, sex, legal status, and, I guess must be said in today's world, political affiliation. Having practiced in Washington, DC for over 40 years, that last category came up frequently as I encountered parents who were elected officials and/or involved in jobs in the political realm. In keeping with that sentiment, I'll still be keeping politics out of this blog and restrict my pontification to infectious diseases. I'll also avoid commenting on various conspiracy theories and other wild ideas emanating from individuals with no scientific basis for their claims. I will, however, comment on any proposed policies related to pediatric infectious diseases where scientific analysis can enlighten the discussion. Nuff said for now.

Leaves are everywhere, including still attached to trees and waiting to further increase my workload. I'm starting to plan my leaf management strategy; when to clear the gutters, waiting for the county to post its leaf collection dates, reflecting on my love/hate relationship with my garden rakes.

... But Still Waiting on WRIS

Covid is as quiescent as it ever gets, flu and RSV still low but hints of increase. I'll enjoy it while I can. As always, CDC has resources to look specifically at activity in your region.

Potpourri

In spite of the relative calm in infectious diseases, I found plenty of tidbits last week. I'll start with some good news.

WHO Declares Egypt Malaria-Free

The news release commented that this is the culmination of 100 years worth of effort. Forty-four countries and one territory have achieved this certification worldwide, which requires demonstration that malaria transmission from local Anopheles mosquitoes has been stopped for 3 consecutive years. In the WHO Eastern Mediterranean region, only 2 other countries, UAE and Morocco, have achieved this landmark. Given that some of our earliest evidence of malaria in humans comes from studies of ancient Egyptian mummies, it's pretty amazing to see a 6-thousand-plus year trend ended.

Mpox Age Distribution

A recent study from Burundi highlights a trend in recent mpox cases in the region, now seeming to cluster in children disproportionately. Here's the breakdown:

The authors state they could not identify reasons for this unusual age distribution, and I expect we'll hear more about that. They also noted that cases were more severe in individuals 15 years of age and older.

Community Acquired Pneumonia Due to Avian Chlamydia abortus in the Netherlands

One more cause of zoonotic pneumonia to add to our lists, based on this new report. Dutch investigators provide a convincing story for an infection cluster in 1 family, including 1 person with severe pneumonia, occurring in late 2022. This novel avian strain was first reported in 2021, and I suspect we'll be seeing more reports of this organism now with perhaps evidence that human infections have been occurring for some time. I'm especially anxious to hear more about the spectrum of clinical disease, hoping that this is mostly a mild pneumonia.

Iquitos Virus

Just as I was starting to get a feel for Oropouche virus (OROV) disease, now I need to learn about a close cousin (IQTV) that was found to cause infection in a traveler returning from Ecuador. Under the category of more than I needed to know, these viruses are part of the Simbu group of about 20 bunyaviruses including the amazingly named Madre de Dios virus. The traveler in the case report returned after a 10-day trip to Ecuador where he experienced many insect bites and presented with fever, chills, sweats, headache, pain with eye movement, and rash. He was thought to have OROV infection, but he fortuitously presented for care in Atlanta where his samples landed at the CDC and further testing revealed the true culprit to be IQTV. The traveler did not require hospitalization and recovered uneventfully.

Hold the Onions

The only way to have avoided hearing about this month's E. coli O157:H7 outbreak linked to Big Macs is to be completely cut off from all news and social media sources. It is centered in Colorado but also present in several neighboring and nearby states. As of the latest update on October 25, the case total is 75 with 22 hospitalizations and 1 death spread over 13 states.

CDC hasn't yet provided any detail about range of symptoms in this outbreak, but presumably the more severe cases represent instances of hemolytic-uremic syndrome. Although O157:H7 and HUS is classically associated with contaminated ground meat, that source didn't seem to make sense in this outbreak. All of these fast food chains have automated cooking methods that would reliably kill bacterial pathogens; it is conceivable the equipment could break down in one restaurant, but not particularly plausible for so many sites occurring at once. The hunt changed to uncooked foods with raw onions now the presumptive culprit.

These circumstances reminded me of a child with no travel history that I diagnosed with typhoid fever decades ago. It was eventually traced to the shrimp salad at a local McDonald's restaurant, prepared by a modern-day Typhoid Mary.

ACIP Meeting

I'd be totally remiss if I didn't mention the regular meeting of CDC's Advisory Council on Immunization Practices last week. However, most of the newsworthy items concerned adult vaccinations (e.g. lowering the recommended age for pneumococcal vaccines). They did approve the 2025 child and adult immunization schedules The final version is not yet available, but you can look at the drafts. Note that a second dose of covid vaccine will be recommended for immunocompromised and high risk children adults 6 months after the fall vaccination. Also see ongoing tweaks to the meningococcal vaccine recommendations appearing on slide 27.

While we wait for official pronouncements, you can find a summary of all the meeting recommendations here.

Tag: E. coli O157:H7

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