Month: September 2023

Yes, I know this blog always deals with bugs, but this time I'm referring to the slightly larger bug forms. I think I saw my first Phoebis sennae in Maryland on Friday. My wife and I had taken advantage of the unusually delightful weather to make a dash to the West River in Maryland for some kayaking. I wasn't expecting to see a butterfly haven but happened on a flutter of butterflies right beside a public boat launch area.

First I guess I should mention the other creatures you expect to hear about in these pages, recognizing that viruses aren't considered life forms so maybe are not analogous to butterflies.

Pediatric Mpox

A new article nicely describes Mpox in the pediatric population. Multiple investigators from the WHO focused on the 1.3% of Mpox cases globally that occurred in individuals under 18 years of age. Only 1 ICU admission and 0 deaths were reported. Mode of acquisition below shows that contact with infected individuals and contaminated material predominated in younger children, while sexual encounters were most common in adolescents. Some of the analysis was limited by lack of complete data such as sexual history and, to a lesser extent, clinical findings. I don't think this study included US patients, but they have been reported separately a year ago.

Vaccination Against Disease X

No, this isn't something Elon Musk (he of the bizarre fascination with the 24th letter of the alphabet) came up with. Here, Disease X refers to unknown pathogens with the potential to cause pandemics. The University of Oxford just announced US$80 million in funding to continue research on the ChAdOx technology used for the Oxford - AstraZeneca covid vaccine marketed as Novavax in the US. This vaccine was associated with rare thromboembolic events and is no longer available in the US and UK. Let's hope future pandemic preparation continues to receive funding.

COVID Variant Hand-Wringing

I still see a lot of attention to covid variants, which is appropriate, but it must be tempered by the observation that the numbers are very low. Of course, any interpretation of these numbers must be made with the recognition that cases, hospitalizations, and even deaths are not being tracked in the same way as at the height of the pandemic and thus difficult to compare to prior numbers.

The BA.2.86 variant is a major focus in spite of its very small numbers. As I've mentioned before, this attention is due to the large number of mutations that could improve its ability to escape immunity from vaccines and prior infection. The latest CDC assessment again states that there is no evidence it causes more severe disease, and the main question is still immune escape and "fitness" qualities, i.e. how well it can outcompete other variants to become predominant.

The UK has a more detailed analysis (I think I'm becoming favorably biased towards the UK reports). Here's a timeline of the current 27 BA.2.86 cases identified worldwide so far. Note that for a BA.2.86 case to be identified, the infected individual would first need to undergo testing and then have that sample sequenced, so just the tip of the iceberg here.

BA.2.86 also has been seen in wastewater samples all over the world for some time. Here is an assessment from the UK: "...the variant is present in multiple countries on multiple continents, detected at a low prevalence amongst clinical cases or in wastewater. Although an increasing number of countries are reporting detection, there is as yet no clear signal of growth within any of these individual countries...No conclusions can be drawn about the fitness of the variant based on this data, and a full range of options – from less fit than other circulating variants, to a large jump in fitness – are still possible, given the available data."

As always, stay tuned.

Number Needed to Vaccinate for Covid Vaccine

To continue in my Anglophilic vein, the UK also provided a wonderful analysis of NNV. I copied one of their tables here (IS denotes immunosuppression):

The NNV reflects the number of individuals in those categories that would need to be vaccinated to prevent one additional hospitalization. The NNV is lower in the immunosuppressed and elderly populations. The estimates don't go below age 15; as you may be aware, vaccination of children in the UK is less of a priority than in the US, so it's hard to get NNV in young children in the UK.

In general, if one looks at covid vaccination at the individual level, at every age the benefit/risk ratio of the vaccine outweigh those of natural covid infection. From a population health perspective, the cost of vaccination to society increases when younger age groups are included in the analysis.

Vibrio vulnificus

CDC issued a health alert advisory this past week. If you are unfamiliar with severe infection related to V. vulnificus, please read this. Most notable and perhaps underemphasized in the lay press are the risk factors for severe, life-threatening disease: diabetes, immunocompromised states, and liver disease. Make sure your patients with these risk factors are aware of steps to avoid this infection and what to do if early signs develop. The infection can move very rapidly in these high-risk patients.

Vladimir and Me

I'm speaking of Nabokov, the writer. He is most known (and in some misguided circles, despised) for his novel Lolita, published in 1955 (1958 in the US). Fewer people are aware that he was an accomplished lepidopterist. The September 4 issue of the New Yorker reprinted a 1948 essay where he extolls the delight of butterflies and related creatures. Who knew that a mixture of molasses, beer, and rum applied to tree trunks attracts hungry moths at night? Read the essay if you have a chance, I think limited free access is available to non-subscribers. You'll experience some incredible writing, even if you aren't convinced to love butterflies and moths.

Phoebis sennae courtesy of the US Forest Service.