malaria – Pediatric Infection Connection

The Year in Review

Bud WiedermannDecember 29, 2024December 29, 2024Leave a comment

It's fashionable for this time of year to give some reflections on the events of the last 12 months; seemingly every pundit/publication does it in some form or another. I won't buck the trend. What follows is a bit of a "highlight reel," plus the 3 things I'm watching closely for next year.

The Unexplained Explained

Recently we all had the opportunity to watch as a mystery outbreak unfolded in the Democratic Republic of Congo. Was it a novel pathogen set to launch a new pandemic or simply a localized outbreak of a known pathogen, complicated by poor health resources delaying accurate diagnosis and treatment? It took a little longer than I predicted to unravel everything, but we now have an answer from WHO as of December 27. That's still pretty quick, the original alert from the Panzi health zone in the Kwango province was November 29. I'm reassured that our global public health system is working well for outbreak detection.

The case definition used for investigation was fairly broad: "any person living in the Panzi health zone from September 2024 to date, presenting with fever, cough, body weakness, runny nose, with or without one of the following symptoms and signs: chills, headache, difficulty breathing, malnutrition, body aches." Here's an excerpt from the report:

"As of 16 December, laboratory results from a total of 430 samples indicated positive results for malaria, common respiratory viruses (Influenza A (H1N1, pdm09), rhinoviruses, SARS-COV-2, Human coronaviruses, parainfluenza viruses, and Human Adenovirus). While further laboratory tests are ongoing, together these findings suggest that a combination of common and seasonal viral respiratory infections and falciparum malaria, compounded by acute malnutrition led to an increase in severe infections and deaths, disproportionally affecting children under five years of age."

In other words, it was a combination of known pathogens already present in the area, layered on a background of falciparum malaria and malnutrition: a perfect storm. Let's hope the added health resources will dampen the outbreak in this very rural, isolated region of the DRC. Nutritional support is particularly needed.

WHO 2024

The WHO published its look back at 2024, including "highlights, breakthroughs and challenges." Many countries achieved milestones in either elimination or significant decreases of a number of diseases, including human African trypanosomiasis, leprosy, lymphatic filariasis, trachoma, malaria, measles, and mother-to-child transmission of HIV, syphilis, and hepatitis B. Their Expanded Programme on Immunization celebrated its 50th anniversary this year, with an estimated 154 million deaths prevented, most of them infants.

WRIS

CDC took a bit of a holiday break this week, so the level of detail in reports is less. However, Winter Respiratory Infection Season is officially High nationally.

The big 3 (covid, influenza, and RSV) all are increasing at this point. I'm hoping they don't peak at the same time and cause big logjams in healthcare settings.

What I'm Watching For

Mpox

In spite of the few cases in North America, Asia, and Europe, mpox is still primarily an African problem. As we know, however, no communicable disease in one area is just a problem limited to that area - international spread is always a few contacts away. In that regard, I found a recent review/opinion article enlightening.

Of interest, smallpox (vaccinia virus) vaccine protects against mpox infection. Our success in eliminating smallpox and subsequent cessation of smallpox vaccination led to a new population susceptible to mpox infection. A major hurdle to control the outbreaks will be vaccinia virus vaccine testing and distribution to high risk populations.

Avian Influenza

The influenza A H5N1 viruses now circulating in birds (both domestic poultry and wild birds) and dairy cows is the most likely source of a new pandemic, but fortunately the risk is still very remote especially if the public health system can keep on top of tracking infections and characterizing variants.

In the past week we learned that feeding your cat raw pet food derived from poultry is not a good idea, it resulted in 1 cat death in Oregon. I think most of us could have predicted that. One thing for cat owners to keep in mind is that the current avian flu, while still causing some respiratory symptoms in felines, is noteworthy for neurologic symptoms.

Also this week we learned about the mutation found in the hemagluttinin gene segment in the Louisiana human patient with severe avian flu illness. This is the H1 part of the virus which is important for attachment to respiratory epithelial cells. Mutations in this area can increase the effectiveness of spread in humans. However, it is completely expected that a human infected with the virus and experiencing severe disease would develop these types of viral mutations. What would be more concerning is if an isolate from a bird or cow developed such mutations, because of the potential for wider spread.

The risk for widespread human A H5N1 infections is still extremely low. I'll be watching in 2025 for any evidence of human-to-human transmission as well as any significant changes in the virus circulating in the wild animal kingdom. Again, I'm reassured that surveillance is allowing for rapid sequencing of human isolates. I hope that resources continue to be available to track this virus in animal and human populations.

SARS-CoV-2

Covid remains a wild card. It has perhaps the highest mutation rate of any virus causing human disease, it has yet to develop a true seasonality like other coronaviruses making it difficult to plan vaccination recommendations, and infections are still relatively frequent plus underreported due to lack of resources for testing, public apathy, and misinformation/disinformation fueling political decision-making. In short, we're in big trouble if another new variant appears with significantly greater pathogenicity and infectivity.

WHO published another year in review on covid that included a big overview of what's happened since 2020. They do note that our tracking systems worldwide are diminished compared to earlier in the pandemic, so recent data are likely to be significant underestimates. In the post-pandemic phase, we all need to transition from the type of extensive pandemic case tracking into a more sustainable surveillance system similar to what we do for influenza.

I was surprised to see some areas blank for what's going on the US, perhaps due to delayed reporting, and I was also a bit overwhelmed trying to decide what graphs to display here; if you're interested I'd suggest perusing the document itself. First, I've copied a quick highlight summary:

While there are periodic waves of COVID-19 in some countries, SARS-CoV-2, the virus that causes COVID-19,
largely circulates without clear seasonality and continues to infect, cause severe acute disease and post
COVID-19 condition.
The impact of COVID-19 has varied by country depending on the circulating variants, national policies,
capacities to respond and access to countermeasures.
WHO’s ability to monitor circulation, severity, virus evolution and impact is challenged by reduced
surveillance, testing, sequencing, limited integration into longer term infectious disease prevention and
control programs, and reporting, as Member States adapt from crisis management to longer term prevention
and control of COVID-19.
Changes to COVID-19 surveillance over the past five years have been consistent and expected, adapting to
the changing landscape of the pandemic. Many Member States are transitioning from comprehensive case
reporting to integrating SARS-CoV-2 monitoring into existing respiratory disease and infectious diseases
surveillance systems. This is an important step towards sustainable infectious disease surveillance,
monitoring and risk assessment. At the present time, the integration of SARS-CoV-2 into existing influenza
surveillance systems is variable across regionsranging from 41% in countries from the Western Pacific Region
to 96% in countries in the European Region.

Here's a great overview of the past few years on a global level.

Even with more inaccuracies in tracking recently, it's nice to see how far we've come in lowering cases and deaths.

Here's a look at deaths by age group, but what isn't apparent in the graph is that mortality rates in infants are comparable to mortality in 20-45-year-olds. Another advertisement for vaccination of pregnant people, who themselves are in high risk group.

And here's the crazy lack of seasonality expressed as percentage of positive tests. I might be tempted to see a trend towards winter seasonality, but remember these data include the southern hemisphere and thus we should see a biphasic pattern if/when seasonality develops.

And lastly a look at how far our variants have drifted over time.

Auld Lang Syne

My apologies to Scotsman Robert Burns, but I must turn to Londoner (with Scottish heritage) Sir Rod Stewart for my favorite version of the song at Stirling Castle in Scotland, complete with bagpipes.

Wishing everyone a Safe and Happy New Year. See you next year.

Autumn Has Broken ….

Bud WiedermannOctober 27, 2024October 27, 2024Leave a comment

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.

Is There More to Life Than Infectious Diseases?

Bud WiedermannApril 28, 2024April 28, 2024Leave a comment

Well of course there is, that's why I try to sprinkle my weekly posts with comments on bird feeders, squirrels, novels I've been reading, and other escapades. This past week I happened upon a former colleague of mine who has taken this to new levels, much to my enjoyment.

We seem to be free of serious infectious diseases drama in the past week, unless you are a dairy cow.

Avian Flu

Initially only previewed in news reports and even now lacking details, one thing is clear: influenza A H5N1 infection in US dairy cows is much more widespread than previously revealed. We were surprised by this because asymptomatic infection is common and cow testing was only being performed in symptomatic animals. (This is reminiscent of the early days of covid!) The FDA and Department of Agriculture both report finding positive avian flu PCR tests in 1 out of 5 samples of pasteurized milk tested, although I can't find details about the total numbers and the geographic distribution of milk samples tested.

Of course, a positive PCR merely means that nucleic acid has been detected. It is highly likely that pasteurization inactivates H5N1 virus, and preliminary reports from FDA suggest this is true. Again, details are not available, but certainly no cause for panic about drinking pasteurized milk.

The take-home messages are clear: 1) H5N1 infection is highly prevalent in US dairy cow herds if 20% of all milk samples are PCR positive; 2) there is even more reason now to avoid ingestion of unpasteurized dairy products; and 3) USDA, FDA, and CDC are performing poorly in providing transparency and detailed evidence to the public. They say they are working on this, let's hope we see the fruits of that labor in the coming few weeks.

And, to give our federal agencies some credit, CDC has a spiffed-up web site for avian flu now, with weekly updates. Here's a quick view for the week ending April 20:

Note that this site deals only with human disease. If you want to get more on dairy cattle, you'll need to go to the USDA site. Here you can realize how geographically widespread the situation is.

USDA now has new guidelines for testing dairy cattle being transported interstate. Perhaps testing needs to be expanded beyond just interstate transport.

Covid Calm

Covid activity continues to fall, and weekly deaths now appear to be consistently less than 1000 even considering there is significant reporting delay for covid deaths. The vast majority are in the elderly.

Two new studies appeared highlighting covid vaccine side effects in children. One was a prospective cohort study utilizing insurance databases that likely carried some risk of classification errors because the authors did not perform any medical records review for verification. The study confirmed the known risks for myocarditis or pericarditis for ages 12 - 17 years with the Pfizer vaccine. Also, they found a possible safety signal for seizure occurring following both Pfizer and Moderna vaccination in 2 - 4 or 5 year-old children. This is pretty iffy; as they explained in the body of the text, it may simply be an artifact of how they defined the baseline seizure rate as a comparison number. This is worthy of further study, but in my opinion not something that should be put on the list of definite side effects yet.

The other study was a massive (3.9 million children) look at covid cases in California from 4/1/20 through 2/27/23, again using an administrative database. The article has too many explanatory graphs to show here, but the bottom line from the authors' predictive models suggests that vaccination prevented about 146,000 covid cases in 12 - 15 year-olds, 230,000 cases in 5 - 11 year-olds, and 168 hospitalizations in 6 - 59 month-olds. The authors did not find any association of vaccination with numbers of cases in the youngest age group, possibly because the numbers of vaccinated children were too small during the study period.

Our friends across the pond reported on various covid features from this past winter, November 2023 through March 2024. Results are based on self-reported data from a longitudinal survey study. Here are the main points:

An estimated 3.3% (2 million) of people living in private households in England and Scotland were experiencing self-reported long COVID (symptoms continuing for more than four weeks after a confirmed or suspected coronavirus (COVID-19) infection that were not explained by something else).
Long COVID symptoms adversely affected the day-to-day activities of 1.5 million people (74.7% of those with self-reported long COVID), with 381,000 (19.2% of those with self-reported long COVID) reporting that their ability to undertake their day-to-day activities had been "limited a lot".
Those in the youngest (aged 3 to 17 years) and oldest (65 years and over) age groups were the least likely to test positive for COVID-19 during the study period.
Those who have had a vaccination since September 2023 were less likely to test positive in the early waves of the study period (1 and 2); in later waves of the study period (3 and 4) there was no statistical difference.
Participants in the oldest and youngest age groups who did test positive in the study period were also less likely to report symptoms consistent with "influenza-like illness" compared with those in the middle age groups.

It's hard to find such recent data. I think this gives us a good peek at the future, assuming we don't have some major change in virus virulence or transmissibility.

Encouraging Progress in Malaria Prevention

I don't usually mention phase 2 trials because they are often much removed from clinical applicability and might change significantly once phase 3 trials are completed. This study is cause for optimism, so I'll break my custom here. Investigators in Mali performed the trial, part of which looked at 225 children randomized in equal numbers to a long-acting monoclonal antibody against Plasmodium falciparum with low dose, high dose, and placebo groups. Infection and clinical malaria was much less in the treatment groups.

The antibody is administered subcutaneously, a plus in resource-poor environments. If further studies confirm efficacy, this could save many lives.

Measles

No new cases were reported in the past week, good news though we know there will be more eventually. Also, I've been looking for more reliable assessments of worldwide activity and found another resource for Europe, the European Centre for Disease Control and Prevention. Updates appear only monthly. Here's what the most recent report, February, looked like:

Romania is the major hot spot, but note that many popular tourist destinations are represented. Here are current CDC recommendations that apply for all international travel:

Fiddlin' Will

By a happy occurrence in my web wanderings, I discovered a former colleague of mine was performing with his band, the Goldbug Revival, at a Salvadoran restaurant near my home. I crossed paths briefly with Will Sears when he was an infectious diseases fellow at NIH; he is now a medical officer at NIAID. However, in his "spare time," he is an accomplished musician. I was thrilled to see him on the fiddle and his wife Sarah singing lead at the band's first live performance and Sarah's first performance in front of a microphone ever. They were excellent!

See you next week. I'll be listening to some John Prine music in the meantime, waiting for Goldbug Revival's first album to drop. Prine was an early covid victim, dying in April 2020.

It’s Winter Respiratory Season, Complete with Hype

Bud WiedermannDecember 3, 2023December 3, 2023Leave a comment

Yes, the winter respiratory illness season has ramped up in the US. Predictably, so has the hype. I even saw a term, "white lung syndrome," tossed out. It's a completely inappropriate description especially when one considers the main lower respiratory disease agent circulating now is a mild one, Mycoplasma pneumoniae.

Before we dive into winter respiratory pathogens, let's touch on a few other noteworthy events from the past week.

Watch Out for Cantaloupes (and many other foods)

CDC announced a new Salmonella outbreak alert this past week, covering 34 states and resulting in over 60 hospitalizations so far. Be particularly cautious of pre-cut cantaloupe products. Perhaps more revealing, however, is the fact that we have 2 other Salmonella outbreaks being monitored now (dry dog food and fresh diced onions) plus 4 others that have ended recently (backyard poultry, raw cookie dough, ground beef, and small turtles). Salmonellosis can mostly be avoided by knowing about high risk situations (e.g. poultry, ground meats, reptiles, poorly washed raw foods) and practicing good handwashing, food washing, and cooking thoroughly, as well as by refrigerating leftovers promptly.

WHO World Malaria Report

WHO released its annual report, and it's no surprise we are behind schedule for decreasing malaria cases worldwide. It's a very long, detailed report even allowing for the fact that some details appear in a few different languages. Some key details:

Rapid detection assays have been very helpful in diagnosing Plasmodium falciparum infections in particular, but new mutations in the histidine-rich protein 2 gene may allow these organisms to escape detection.
As always, resistance to antimalarials is spreading, requiring ongoing monitoring.
Not to be outdone by the pathogen, the vectors (mosquitoes) are increasingly becoming resistant to insecticides. This has led to new recommendations for mosquito netting in malaria-endemic countries.
And last, but not least, climate change. Here's a direct quote: "WHO has declared climate change to be the single greatest threat facing humanity."

I liked this graphic for visualizing malaria case distribution geographically.

More Concern for Invasive Group A Streptococcus

The Pan American Health Organism just issued a new alert for iGAS infections in Argentina. This joins a growing list of reports in a number of countries, primarily in Europe. Research is pointing to new M1 mutations with toxin production that might confer increased virulence.

Winter Respiratory Illness Season

Clearly I need to switch from calling this a winter respiratory viral season to a winter respiratory illness season; not all the pathogens are viruses, and of particular note is M. pneumoniae, a free-living organism in the class called Mollicutes. Technically they are bacteria, but they lack a cell wall and I think it's a bit misleading to the general public to refer to them as bacteria. Nonetheless, they aren't viruses. The organism is very difficult to grow in culture, requiring special media and expertise as well as 1-3 weeks incubation, but now it is included in most multiplex respiratory pathogen panels so easier to diagnose. Serologic diagnosis is fraught with false positives, about the least useful serologic testing for human disease that I know of.

"Fried egg" image of M. pneumoniae in culture:

One important thing to know about mycoplasma disease is that it is endemic everywhere, but epidemics occur about every 3 to 7 years and last anywhere from 1 to 2.5 years. I've witnessed this myself several times in my practice in the DC area, and it appears that a new mycoplasma epidemic partially explains the larger numbers of respiratory diseases in Denmark (you may need Google translate) and the Netherlands.

Perhaps more importantly, it's been very difficult to show that antimicrobial treatment has any benefit for illness caused by M. pneumoniae, which is clearly a self-limited infection. Probably if treatment has a benefit it would need to be initiated very early in the disease course. Testing for the organism requires a relatively expensive multiplex PCR assay and probably isn't worthwhile to test for the usually mild "walking pneumonia" version of the infection.

By far the biggest hype in the lay press (and from some congressmen) is the surge in respiratory illness in China, especially in northern regions. However, we do have some reassurance from the WHO taken from review of Chinese reports (Google translate again helps somewhat here). It appears that what is going on is simply an increase in known respiratory pathogens, rather than a new pathogen that China is hiding from us. I can add anecdotally that, as I track reports in real time and compare to the December 2019/January 2020 tracking I was doing, this looks nothing like the new appearance we saw with SARS-CoV-2. That doesn't mean there isn't something new circulating at low levels, but certainly no cause for alarm or to call for travel restrictions.

Remember that China only emerged from their "zero covid" lockdown a year ago, so this is their first full winter respiratory season with most children having no experience with any of these respiratory pathogens the past 4 years. As we saw in the US last winter, this likely produces a temporary situation resulting in increased numbers of cases and increased disease severity.

On the sort of good news side of covid, CDC reported benefits of covid vaccination for children 6 months to 4 years of age from a very recent time period covering July 2022 through September 2023. Vaccine effectiveness (receipt of at least 2 vaccine doses) for preventing acute care visit or hospitalization was 40%, though with a large confidence interval due to the relatively small numbers of events. The somewhat downer side of the report was that only 10% of the 7400+ children in the study had actually received > 2 vaccine doses.

Moving on from covid, RSV activity in RSV-NET is taking off, it is now full-blown RSV season.

Flu is heating up in more parts of the country, but not widespread yet.

Covid also is increasing, and now CDC has a better display for wastewater tracking:

The above is current for the week ending November 25 and predicts we will see a winter increase in covid illness. This is supported by a slight increase in positivity rate in covid testing in CDC data. However, you can see most of the recent uptick in positivity rate is being driven by influenza and RSV. If wastewater is truly predictive, we'll see the covid curve start to rise more dramatically in the coming weeks.

A Chuckle to Share

I loved this brief blurb in the November 20 issue of The New Yorker (I'm way behind in my magazine reading, blame Thanksgiving holidays). Every parent (and grandparent) will identify with this fictional list of communications from a nursery school to parents, announcing outbreaks of lice, pink eye, smallpox, "pirate's gastroenteritis," and rinderpest.

I Didn't Forget Diego Rivera

Last week I challenged you to name the organisms depicted in various Diego Rivera murals as collected in a recent article. According to the authors, figure A represents Salmonella typhi, though that seems a stretch to me. Figure B is easier, it looks a lot like the Gram negative intracellular diplococci seen with gonorrhea. Figure C shows spirochetes, mostly likely syphilis, but D is vague again, some sort of Gram positive intracellular cocci. Take your pick.

A Week of Autochthony

Bud WiedermannAugust 20, 2023August 20, 2023Leave a comment

Last week I was struggling to come up with enough new items to fill the post; this week I'm wrestling to pare down the list of topics. We've had some more concerning news about autochthonous tropical infectious diseases cropping up, but before I turn to that....

Is Covid Coming Out of the Doldrums?

Lots of headlines about this in the past week, some more hysterical than others. Staying alert, not panic, is the appropriate response.

First to wastewater. Looking at the past 6 months in Biobot, every US region is trending up, notwithstanding a slight drop in the purple midwest region.

Now look at the same graph spread out over a longer time:

So yes, we've had an upward blip recently, but nothing as dramatic as what accompanied serious clinical outbreaks in the past.

The other hype is about newer variants. Fortunately, we're still talking about omicron and primarily from the XBB subvariant group. I'll turn to the UK's nice graphs to highlight; results are similar but not identical to the US.

This Sankey diagram gives you an idea of the relatedness of strains:

The key question is how well the proposed autumn covid vaccine, derived from XBB.1.5, works against these newer variants. The answer is based mostly on conjecture at this time, we have no peer-reviewed hard data yet. The best guess is that it will not protect much against infection itself, nor will prior natural immunity. However, for the more important protection against severe disease, hospitalization, or death, it is likely to have an impact. Jennifer Abassi, a medical news reporter for JAMA, published a nice discussion. CDC and IDSA recently posted a brief explanation. Also in the news the past few days has been a newer variant, BA.2.86, now seen in a few countries sporadically including the US. It's much too early to know if this will become prominent.

CDC published updated data about monovalent and bivalent vaccination in the 6-month to 4- or 5-year-old age groups that showed good effectiveness in protection against urgent and emergency care visits. Also important to note is that these are relatively uncommon events in this age group, which is why you see different recommendations for vaccination in the US versus the UK for example. Going from the last section of Table 2 in the article, rates of these care visits from 12/24/22 to 6/17/23 were 4.4% in the unvaccinated group versus 0.9% in those who had received at least one bivalent vaccine dose. With a little arithmetic, the number needed to vaccinate at this level to prevent one additional ED/urgent care visit is about 30.

Reason to Avoid Proton Pump Inhibitors

French investigators published a cohort study linking use of PPIs in children to higher risk of serious infections. It included over 600,000 children receiving PPIs and a similar number as a control group not receiving PPIs, followed for a few years. The risks for serious infections as well as a number of categories of infection types were significantly increased. Most of the children had significant comorbidities. This association has been known in adults for a long while and is likely based on a variety of PPI effects including elevated gastric pH and alteration of the GI microbiome. That's not to say PPIs shouldn't be used in children, but there is a clear risk that should be explained to parents.

RSV Already in Florida

Florida is now seeing RSV infections in some jurisdictions. This isn't too surprising; Florida has a very different seasonal epidemiology than does most of the US:

It remains to be seen how RSV seasonality will stabilize in the post-pandemic/isolation era. A group in the Netherlands recently reported a switch to year-round transmission during the pandemic.

Along similar lines, a US study showed that ICU admissions for RSV consisted primarily of infants without risk factors; the study does have significant limitations. Findings may reflect the lack of partial RSV immunity conferred by prior RSV exposure of both mothers and infants.

It's still time to plan for use of monoclonal antibody and, if approved, maternal RSV vaccination. AAP and ACIP have a nice discussion available. Lots of logistical hurdles remain.

Autochthonous Malaria and Dengue

I posted about autochthonous malaria in Florida and Texas on July 2 and 9, and on autochthonous dengue fever in Arizona on 11/20/22. See the July 2 post for more about the definition of autochthonous infections.

Now we have a report of 11 autochthonous dengue cases in Florida. Closer to home, we've had a report of 1 case of autochthonous P. falciparum in a Maryland resident in the National Capital Area region. Falciparum malaria is significantly more dangerous than the vivax forms reported in Florida and Texas. Very little information was provided, but the letter does have links to good clinical information sites.

Autochthonous infections are tricky to diagnose given the lack of travel history to an endemic area. Climate change has expanded the geographic range of many insect vectors of disease. All clinicians should be aware of these diseases when evaluating febrile patients.

As a final note, my web wanderings about autochthony taught me something new about the term. Sadly, it has been used in a negative political (and racist) sense. An "autochthonous" flag protest disrupted a 2014 soccer match between Serbia and Albania.

Tag: malaria