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Tag: COVID-19

Published on Leave a comment on Winter Distractions

My soon-to-be daughter-in-law recently gave me a bird feeder - not just any bird feeder, but a smart one that has a camera connected to my wifi that takes photos and videos of any birds that show up. I had my first visitors this morning, a few days after I stocked it with birdseed.

In the meantime, winter is here.

WRIS

A lot going on with our Winter Respiratory Infection Season, including some new items.

CDC issued new (or actually old) guidance for use of the long-acting monoclonal antibody nirsevimab for preventing RSV infection in young infants. The change was prompted by the announcement of greater availability of nirsevimab because the manufacturer released an additional 230,000 doses this month. Previously the guidance had indicated that the product should be prioritized for just a subset of infants at higher risk, but now recommendations are to go back to the original plan to administer to all infants less than 8 months of age as well as to infants 8-19 months of age with high risk conditions:

  • Children who have chronic lung disease of prematurity who required medical support (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) any time during the 6-month period before the start of the second RSV season
  • Children with severe immunocompromise
  • Children with cystic fibrosis who have severe disease
  • American Indian and Alaska Native children

If supply is still limited in your particular area, then prioritization should be used as before. Still a bit vague but very important are all the nuances for ordering, administering, and being reimbursed for the product.

Along that same line, RSV may have peaked nationally.

Even with some good news about RSV slowing down, there's still plenty to go around. Also, influenza continues to drive a lot of healthcare usage for all ages around the country. Here is the percentage of emergency department visits due to the various respiratory infections:

Be aware that this site allows you to look just at your local jurisdiction - here is Maryland:

Covid

This week covid deserves a separate heading with a few new twists. Wastewater tracking once again has accurately predicted a surge in infections.

The JN.1 variant has increased rapidly and is projected to be the predominant covid strain in the US, but without any indication (yet) that it has increased virulence.

This might be a good time to review a bit about variants and also some recent covid findings. Variant nomenclature is confusing to me, I can only imagine how the general public sees this. Here is an evolutionary tree from the same CDC weblink as above.

The nomenclature is from the Pango system, but most people are more familiar with the WHO classification: the delta variant (remember those horrible days?) is B.1.617.2 near the left of the diagram. Omicron is represented in both BA.1 and BA.2. Now here's the important part when we consider new variants, immune-escape, and vaccines: JN.1 has developed on the BA.2 side, just like XBB but on a different branch of the tree. Remember that our current vaccines are based on XBB. As I've mentioned previously, XBB vaccine antibody seems to neutralize JN.1 pretty well in the test tube, but all vaccine (and natural infection) immunity declines significantly within a few months after vaccination or immunization. I would still expect the current vaccine to be pretty good for protecting against severe disease with JN.1 infection.

Although near and dear to my heart, I don't usually talk about old folks in this blog. However, a study of old folks in the Netherlands lends support to the idea that current vaccines are effective against new variants. Without going into details, you can see this study has very recent data and show excellent effectiveness for hospitalization and ICU admission for old folks. It's likely this benefit translates to the younger population that of course has lower rates of hospitalization overall.

Another recent study sheds some light on a question I've been wondering about for some time, namely how common asymptomatic covid infection might be in the omicron era. You might recall that one of the early surprises in 2020 was that asymptomatic infection was both common and very important for viral spread. That made the pandemic much more difficult to control. Now we have data from Hong Kong where rather unique epidemiologic circumstances prevailed. With a population of 7.5 million, Hong Kong officials had still had managed to prevent covid spread very effectively prior to the omicron era, with only about 0.5% of the population having been infected. That ended in early 2022, but it also offered researchers an opportunity to look at rates of asymptomatic infection during the omicron period because virtually none of the population had been infected previously. Using antibody testing, they estimated that 16% of the population was infected during the first 6 months of 2022 and that the percentage of asymptomatic cases was at least 42% (taken from those with reported SARS-CoV-2 infections) and possibly as high as 72% (looking at combined reported and unreported infections). Wow. That doesn't necessarily mean we would have those same rates of asymptomatic infection in the US where we've had a very different epidemiologic curve over the years, but I think it's likely we have a lot of asymptomatic covid surrounding us now.

Some good news about long covid, AKA PCC (post-COVID-19 condition) in children. This Canadian study looked at pediatric emergency department data and found that PCC was present in only 0.67% at the12-month follow-up periods in children testing positive for SARS-CoV-2. That's not the only good news part of this; the rate in a control group of children testing negative for covid was 0.16%, suggesting once again that other infections can trigger some of these long term symptoms. We have NIH-funded studies in the US ongoing now, with good control groups, that should go a long way in giving us guidance for managing PCC as well as other long-term conditions triggered by infections.

The Tipping Point

FDA officials, including Peter Marks who is the director of CBER, recently published a viewpoint article about a vaccination tipping point, i.e. the fact that vaccine hesitancy issues have resulted in a severe decrease in immunization coverage, opening us up to major outbreaks soon. I mention this both because it perfectly supports my views expressed in recent weeks but also it gives me a chance to give credit where credit is due. The term "tipping point," as applied here, often has been credited to Malcolm Gladwell. However, his popularization of the term in a sociologic context earlier this century should go to Morton Grodzins who first adapted this for use in explaining racial integration of neighborhoods in the middle of the 20th century. I'm hoping Gladwell credited him.

In Case You Missed These

Two other articles caught my eye this past week. First is a quality improvement article about shortening treatment duration for children with community acquired pneumonia and skin and soft tissue infections. If you're one of those practitioners who still treats these for 10 days (because we have 10 fingers), check it out.

Secondly, I was attracted to a report about variation in rates of how primary pediatric providers use pediatric subspecialty consultations. Although not the main focus of the report, I was most drawn to the mention that the top 2 conditions for using a pediatric infectious diseases specialist were positive tuberculin skin test and inactive tuberculosis. This jives with my personal experience and certainly points to opportunities to lessen use of subspecialty health care. Multiple resources exist for managing latent tuberculosis infection, including the AAP's Red Book, the CDC, and UCSF's Pediatric TB Resource Page.

For the Birds

My first video stars at the bird feeder were a white-breasted nuthatch, maybe a tufted titmouse (looks a lot like the nuthatch, I couldn't figure it out), and a house finch. When I received the bird feeder, I immediately wondered how best to avoid attracting squirrels and other rodents. I did a bit of web searching and then journeyed to my local bird authorities at the Woodend Nature Sanctuary who of course turned out to be the most helpful. I armed my feeder with capsaicin-treated safflower seeds, not a favorite of squirrels and the like, plus birds can't taste the hot pepper. So far the birds seem to like it.

As for me, it appears I've fallen down another rabbit hole, similar to my butterfly fascination. My wanderings have now included a look at how climate change is affecting our bird populations, as projected by the Audubon Society (apologies for using his name, now controversial, but the Society hasn't yet changed it) in their field guide.

Here is how things will change for the white-breasted nuthatch's winter range with a 1.5 C increase in temperature.

For the tufted titmouse

and the house finch

With more severe temperature increases, the ranges are altered more dramatically. I still hope for some action that will reverse these trends.

Published on Leave a comment on The Future is Bright

2023 wasn't exactly the best of years, but at least we didn't slip back into pandemic circumstances. I fear we will see some "old" infections become new again in 2024. General immunization rates are falling; even before that, we saw plenty of pertussis and even some tetanus, but now we may become reacquainted with measles and varicella, among other vaccine-preventable diseases. Time for some of those younger pediatric healthcare providers who have never seen children with these infections to hit the textbooks again - how's that for a New Year's resolution!

Still, we have lots of reasons to hope for improvements in 2024. Maybe AI won't take over the world but instead will help us practice more effectively.

Short Course Therapy for Febrile UTI in Children

The literature just got a bit muddier with regard to treatment duration for pediatric UTI with a new study from Italy. Investigators in 8 pediatric emergency departments randomized 142 children ages 3 months to 5 years with fever and UTI to receive either 5 or 10 days of oral amoxicillin/clavulanate. The study wasn't blinded, and the randomization occurred on day 4 of therapy when urine culture results were available. UTI was defined as a single organism growing at >100,000 cfu/ml in clean catch urine or > 10,000 cfu/ml in catheterized urine, and subjects were followed for 30 days after completion of antibiotic. After a planned interim analysis the study was stopped early due to finding of noninferiority of the short course therapy.

As you can see, the short course group had numerically lower rates of UTI recurrences during this time period. However, this study's results contradict another study, with a somewhat more reliable study design and definitions, that showed short course therapy to be inferior. I reviewed this earlier study in my July 2, 2023 post. The editorial accompanying the new study is an excellent discussion of weighing the relative merits of the 2 studies. Suffice to say, the jury is still out, and I would stick with 10 days of therapy for febrile UTI in most children.

More Evidence for Using Nirsevimab to Ameliorate Bad Outcomes from RSV

Investigators in 3 European countries conducted a randomized trial of the long-acting monoclonal antibody nirsevimab showing benefits in preventing RSV-associated hospitalization, especially in younger infants. Note that subjects for this study were not eligible for receiving nirsevimab currently in these countries; they were all healthy infants less than 12 months of age, born at > 29 weeks gestation, who were entering their first RSV season.

This was a pragmatic trial, meaning that it was carried out under more "real-world" practice situations rather than within the strict confines of "explanatory" trials used with most therapeutic research studies. It lends more evidence to benefits of nirsevimab for young children.

WRIS (Winter Respiratory Illness Season)

Most pediatric healthcare providers across the country know that we are in the midst of a busy WRIS. This also is a time when data are least reliable due to the extended holiday season - reporting lags a bit, so trends seen now are more likely to be revised in the next few weeks. Still, it's worth a look.

Researchers in Stockholm, Sweden, looked at pediatric hospitalization rates for the 3 "tripledemic" viruses during the period 8/1/21 to 9/15/22 and found that rates were higher for RSV than for omicron covid (the time period was entirely omicron in Sweden) or influenza; note especially the numbers for younger children. I'll be interested to see if this pattern is seen in the US this winter.

CDC has a new (to me) section charting epidemic growth status for covid and influenza, i.e. it depicts, by locale, the growth rates but not the absolute numbers of these pathogens. Another interesting tidbit.

Along the same lines is a monthly crystal ball page from CDC, a bit of sticking their necks out to predict what's in our future for respiratory illnesses. The last report is from November 29:

Lots of uncertainties here, but I appreciate the attempt.

Now for a look at our usual sources for data.

FLUVIEW

Circulating strains are still well-matched to this year's vaccine.

Covid wastewater is increasing, and several healthcare facilities across the country have reinstituted masking and other mitigation practices due to high rates in their communities.

RSV is the one "tripledemic" component that seems to be decreasing in most areas.

So, WRIS this year seems to be a double-whammy rather than a tripledemic, still more than enough to strain healthcare resources. I can only dream how much better people's health would be with widespread vaccine acceptance.

We're Still Safe from the AI Bots

I tried to use an AI program, Microsoft Copilot's Suno, to compose a song about this blog. Specifically, I asked it to create a song about the Pediatric Infection Connection blog using the blues genre. Here's what I got.

Their link doesn't exist, nor is there a pediatric infectious disease specialist Dr. Sarah Jones certified by the American Board of Pediatrics. I did find a Sarah Jones infectious diseases pharmacist at Boston Children's Hospital, but she doesn't appear to have a blog and I don't know if she has children.

I think, for the next year, we'll still be able to keep AI from fooling all of us.

Have a Happy and Safe New Year!

Published on Leave a comment on Happy Holidays

'Tis the season, both for holidays as well as for infectious diseases. Last week's publications featured a wide variety of articles of interest; I'll try to keep it short. As much as I focus on infectious diseases, now is prime time to spend with friends and family.

Multiplex Stool Testing in Gastroenteritis

Children with acute gastroenteritis presenting to one of five different children's hospitals' on site urgent care or emergency departments submitted stool specimens for multiplex PCR testing. The study plan was interesting. For the first approximately 100 subjects, stools were tested regardless of whether the test was ordered by their clinicians (after informed consent from parents, of course). Then there was an intervention period where clinicians received education about the test performance characteristics and clinical management of the infections that the PCR could detect. Regardless of whether or not you look at the article, you may find these educational materials of use in your practice. I did note that the study was funded by NIH but also by the company that manufactures the PCR tests, plus most of the authors were employees of or received outside funding from the manufacturer. This is important because of high risk of implicit bias affecting the report.

"Clinically relevant" pathogen detection rate rose from 2% in the pre-intervention period to 15% after intervention, and return visits decreased after the intervention. There was a trend towards appropriate treatment given post intervention, though not statistically significant.

Indiscriminate use of multiplex PCR assays in acute gastroenteritis has a great potential to cause unnecessary treatment, especially for C. difficile in young children where the carrier rate is so high. It's not surprising that targeted education would be helpful. Also, because the test cannot determine antibiotic resistance patterns, laboratories would be advised to provide reflex susceptibility testing for selected pathogens that might require antibiotic treatment and also have significant resistance rates.

Covid Morsels

A few tinsel-tinged tidbits about covid caught my eye this week. First of all, CDC had a couple reports both suggesting that rebound after Paxlovid treatment was not clinically significant and no different than after placebo treatment. The more substantial report was a closer look at viral RNA shedding from 2 randomized placebo-controlled trials, from both early and later in the pandemic, involving adults only. Rebound rates were about the same in the treatment and placebo groups, both around 6-8%.

We've seen a wide variety of reports about rebound after Paxlovid, but clearly the weight of evidence suggests that viral rebound after treatment does not result in severe disease and that rebound rates likely are not clinically significant from rebound rates in untreated patients. Rebound concerns should not be a factor in decision to treat with Paxlovid.

Also this past week, the WHO stated that antigen composition for covid vaccines should remain the same for now, i.e. based on the XBB lineage of omicron that continues to represent the vast majority of circulating strains worldwide. The BA.2.86 descendents, including JN.1, are rising but with no big concerns yet about greater virulence or significant lack of protection from the XBB.1.5 monovalent vaccines now in use. As I've stated in previous posts, I've not been commenting on emergence of new subvariants unless/until they are shown to have clinical relevance; so far JN.1 does not meet that threshold.

A multidisciplinary panel of infectious diseases, microbiology, and epidemiology experts published an exhaustive guideline for use of molecular diagnostic testing for covid 19. I struggled with how to summarize all the information, suffice to say that the methodology for guideline development and the evidence behind the recommendations are stated clearly. I'll just present the bottom line summary, but please dig into the article for details if you are interested. Note that, if you haven't already, it would be helpful to identify sites near you where nucleic acid amplification testing (NAAT) with quick turnaround of results is available.

A multinational group of investigators summarized reports of laboratory-acquired infections (LAIs) and accidental pathogen escape from laboratory settings (APELS) between 2000 and 2021. Sixteen APELS were reported and involved anthrax, SARS-CoV (the original), and polio (3 each); Brucella spp and foot and mouth disease virus (2 each); and single episodes of variola virus, Burkholderia pseudomallei, and influenza H5N1 virus escape. LAIs were much more common with a total of 94 reports involving over 300 infected individuals. LAIs more commonly involved Salmonella spp, Brucella spp, and vaccinia virus. Although the study doesn't answer the question of SARS-CoV-2 origin, it certainly can inform measures to prevent lab accidents in the future.

Winter Respiratory Illness Season

Cumulatively our winter respiratory illnesses are increasing. I'm interested to see what the holiday school breaks and travel will do to the epidemic curves. I've been trying very hard to streamline finding current data that also is broken down by location so I can see my own local trends; unfortunately I don't find a single best one-stop shopping site for this purpose.

For general virus surveillance besides covid and influenza, look at the CDC's National Respiratory and Enteric Virus Surveillance System (NREVSS). You can then click on links to 4 groups of respiratory viruses (including RSV) as well as to 2 enteric viruses, rotavirus and norovirus. Here's an example of the South Region's (which includes my area of DC, MD, and VA) most recent RSV detection activity:

The CDC's COVID Data Tracker provides an extensive view of various indicators of disease activity, though not of wastewater which is still available at the National Wastewater Surveillance System (see below). Here's a quick view of the Data Tracker's most recent headline:

Wastewater covid continues to rise nationally.

Last but not least, our old friend influenza continues to spread across the country:

Have Your Cake and Eat It Too

I did say at the start this was a time to balance my obsession with all things infectious and my desire to have fun times with family and friends during the holidays, and I'll mention one way to (almost) do both. The annual Christmas issue of the BMJ was released. It always contains a few tongue-in-cheek articles - real research but performed for silly premises. The only infectious diseases-related article this time around was a study of bacterial contamination of hospital coffee machines. Surprisingly to me, the level of true pathogens they found was pretty low. I'm helping with some baking today, fans of the Great British Bake Off will enjoy this article.

However you spend the holidays, please take time to enjoy friends and family.

4

Published on 4 Comments on Synbiotics?

I'm only mildly ashamed to admit that when I saw a recent publication of a randomized controlled trial of symbiotic therapy for post-acute COVID-19 syndrome (PACS), I had no idea what the term meant. Now I know more, and the study brings up some intriguing thoughts but no direct answers.

First, let's talk about a couple other issues.

Winter Respiratory Illness Season

I'm inventing a new acronym, WRIS, just because I can. CDC went so far as to issue a Health Alert Network posting reminding all of us about the low vaccination rates for covid, influenza, and RSV as well as the availability of treatments for the first 2 infections. So far, flu vaccine coverage in the pediatric age range (6 months to 17 years) is about 36%, pretty poor. The post has a lot of good information throughout, but if you're pressed for time please at least take a look at Table 2 with its links for suggestions for discussions with the unimmunized.

Looking at CDC's weekly viral report page, respiratory illnesses continue to increase. Nationally, emergency department visits for WRIS continue to rise, driven largely by influenza. RSV may be past its peak.

RSV hospitalizations might be coming down, though the data are preliminary:

Influenza-like illness remains high in many states in the South:

Lastly, covid is till out there with high levels in wastewater suggesting we'll see a bigger bump in illness soon.

Although I've presented the national picture, be aware that many of these sites have the ability to display findings by state and other jurisdictions, so you can see what's going on in your area.

Is Pediatric Omicron Infection More Contagious Than We Thought?

That's certainly the implication of a recent study looking at duration of viral shedding in infected children over a 90-day period in early 2022. It's important to note that the study looked only at duration of positivity of PCR at high levels thought to link to infectivity, and also at rapid antigen test (RAT) positivity over time. So, it wasn't a direct measure of whether these children actually transmitted infection at home or in school. With this caveat in mind, they found that 25% of children still had presumed infectious viral loads by day 7 of illness, a bit longer than guidelines recommend for isolation. RAT positivity was a mixed bag as usual (the watermark in the graph just denotes "accepted manuscript" as this paper was published for early online access).

This article shouldn't change practice per se. Looking back at publications of covid spread from children, the results are highly variable with some studies suggesting children have little role in spread. With this much variation in study results, likely the issue is multifactorial, making it difficult to come to any broad generalizations that apply across ages, settings, and time.

Meningococcal B Vaccine and Shared Clinical Decision Making

A few weeks ago I mentioned that healthcare providers don't have enough information at their fingertips to allow parents and patients to truly participate in decisions about vaccination. A new publication about meningococcal serogroup B disease rates helps inform the discussion for meningococcal B vaccine. As you may recall, the ACIP and AAP recently updated meningococcal B vaccination information with the approval of a new pentavalent vaccine. Meningococcal B disease in the US is relatively rare, making risks pretty low overall regardless of vaccination status.

The authors looked at rates of meningococcal disease in persons 18-24 years of age in the years 2014-2017, so not altered by any pandemic considerations. They found 229 confirmed or probable meningococcal disease reports, for an overall rate of 0.18 per 100,000 person years. 120 of the 226 cases for which they had college status were undergraduates, the group at highest risk of meningococcal B infection in the US and the main target for any vaccine intervention. Of those 120 students, 89 had infection with serogroup B.

Students attending 2-year colleges did not have an increased risk of infection compared to non-college students. Only 4-year college attendees had increased risk, and the risk was higher among first-year students and among "Greek life" participants, probably because those groups have a bit more crowding and sharing of beverages, etc.

The authors had some excellent advice in their discussion:

"These findings might be useful for patients, parents, and clinicians when discussing whether to vaccinate adolescents against serogroup B before they go to college. Adolescents planning to live on campus at a 4-year college, particularly ones planning to engage in Greek life or attend schools known for their social life, may benefit more from vaccination. Immunity from MenB vaccines is known to wane quickly, but concentration of risk among first year college students means there is an opportunity to prevent relatively more disease by vaccinating students shortly before they go to college so that the timing of maximum protection overlaps with the highest period of risk."

"Requiring or recommending vaccination against serogroup B disease might not be a tenable policy decision for all colleges, but our findings suggest that 4-year colleges with large numbers of students participating in Greek life or with a high party school ranking might be most likely to benefit from such policies, as these schools were significantly more likely to experience serogroup B cases or outbreaks."

Did you catch that party school mention? Another aid for parents referenced in the study was a ranking of party schools. Those with high rankings presumably represent higher risk for meningococcal B disease. No surprise to me, my undergraduate school didn't make the list.

What I really wanted to know was the Number Needed to Vaccinate (NNV), i.e. how many students would need to be vaccinated to prevent 1 additional case of meningococcal B disease. I knew it would be high because this is such a rare event. It took a little work because I needed a denominator - I knew the number of cases, but I didn't know how many were in the risk group. I had to go to a supplementary table in the article, then look at web links to try to choose a reasonable denominator. I settled on the number of full-time students in undergraduate schools in 2017; it included both 2-year and 4-year colleges. That number, from the National Center for Education Statistics, was 12,085,000. Let's assume the MenB vaccines are 100% effective (they are not, but all are pretty close and I got tired of calculations) and that none of those 89 students in the study were vaccinated (the authors couldn't determine precisely the vaccination rates in their study). NNV is the reciprocal of the absolute risk reduction, which is the rate of infection in the control group (89/12,085,000) minus the rate in the experimental (vaccine) group, which we are assuming to be zero. Crunching those numbers gives us an NNV of 135,786. That is to say, we would need to vaccinate that number of students entering full-time college with a meningococcal B vaccine to prevent 1 additional infection. That NNV number is astronomical and orders of magnitude above NNV for other recommended vaccines. If we were doing a cost-benefit analysis of meningococcal B vaccine, it wouldn't jive at all, but what isn't taken into account is the panic that develops when a case of meningococcal disease occurs on a college campus. Also, I made a lot of assumptions in coming to that number, so it's really just a very rough ballpark. Any decision would need to balance vaccine risks (virtually zero; anaphylaxis from vaccination found 33 cases in 25,173,965 vaccination events in one study, a similar ballpark to the rate of meningococcal B disease above.) This all goes to show that using absolute risk reduction can be more informative than looking at relative risks, which are ratios. For example, in the meningococcal B rates study, participation in Greek life carried a 9.8-fold increase in infection risk compared to other students - a high number that doesn't convey the extremely low infection rates. News stories invariably talk about relative risks rather than absolute risks - bigger numbers sell more papers/advertisements.

So, you can see why those quoted discussion points from the authors are so important. If a parent/potential college student asked me about meningococcal B vaccine, I'd start with saying meningococcal disease is very rare but also very dangerous, with a high fatality rate if one is infected. The risk of getting the infection is very low, about equal to risk of having a life-threatening allergic reaction to any vaccine, both being very rare. [The provider could insert in here if they've ever seen in case of anaphylaxis with a vaccine.] If the plan is to attend a 4-year college, live in a dormitory or fraternity/sorority, and have an active "party" life, the risks for infection are higher though still rare. Some people might value having some more piece of mind and choose to receive vaccination; others may not. Regardless, if at school one hears that you have been exposed to someone with meningococcal infection, you need to follow specific guidance from the local health department or student health team without delay - antibiotic and/or vaccination might be life-saving.

What I Learned About Synbiotics

I'm exhausted after too much number crunching, let's look at a new study that certainly is food (pun intended) for thought. A few definitions first:

Prebiotic - a nondigestible food ingredient that promotes the growth of beneficial microorganisms in the gut

Probiotic - live microorganisms ingested to improve the gut microbiome

Synbiotic - a combination of prebiotic and probiotic substances

The randomized, double-blind, placebo-controlled study looked at 463 adult patients in Hong Kong who were previously diagnosed with covid and fulfilled a standard definition of PACS. The experimental group received twice daily oral doses ("sachets") consisting of 3 probiotic bacteria and 3 prebiotic compounds; the control group received vitamin C with inert additives such that the packets of oral doses were identical in appearance, smell, and weight. The choice of synbiotic elements was based specifically on prior Hong Kong microbiome studies that suggested beneficial elements. The main outcome of interest was change in PACS symptoms at 6 months.

Although there was no difference in quality of life or physical activity between the 2 groups, the treatment did seem to have a beneficial effect on several symptoms and was correlated with favorable microbiome changes.

Maybe some progress, we'll need to see more studies on synbiotic therapy for long covid, hopefully expanded to many different populations. I think I'll go get some yogurt for lunch.

Published on Leave a comment on It’s Winter Respiratory Season, Complete with Hype

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.

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