COVID-19
This is going to be really short because I am travelling today.
Long COVID
This paper using Quebecois electronic records data (2022-10-21) found that patients who got dehydrated during hospitalization were more likely to get physical Long COVID. They were no more likely to get mental Long COVID, though.
This paper from USA (2024-07-17) reports that the rate of Long COVID in veterans has fallen from pre-Delta to Omicron, but about 72% of the effect is due to vaccination. Even with the decline, Long COVID is still affecting 7.76% of unvaccinated people who get COVID-19 and 3.5% of the vaccinated people.
Two caveats:
- This was a US Veterans’ Administration study, so overwhelmingly older and male.
- They only looked at first recorded infections.
COVID-Related Excess Sickness and Death
This Research Letter from Germany (2024-07-15) reports that children with presymptomatic diabetes had a 63% higher risk of converting to full-on diabetes if they tested positive for COVID-19.
H5N1
Pathology
This paper from USA (2016-11-11) reports that the first influenza virus that you are ever exposed to gives much stronger protection than later exposures. This type of heavier weighting to the first exposure is called “imprinting”, and it’s usually a bad thing — it sometimes means that later vaccines aren’t as useful as your first vaccine. With H5N1, this turns out to be a good thing for older people and less good for younger people (right now).
Before 1968, H2N2 influenza strains were dominant, and H5 is closely related to H2 — meaning that anybody born before 1968 probably got imprinted with something close to H5N1.
In 1968, the H3N2 strain showed up with the the Hong Kong flu H3 is not as closely related to H5 as H2 is, so people born after 1968 are less likely to get imprinting protection against H5N1. The good news is that H3 is closely related to H7, so people born after 1968 will probably have better immunity to H7N9 — a different nasty bird flu.
Transmission
This paper from Hong Kong (2022-12-18) reports that H1N1 (that nasty one which started (re)circulating in 2009) exposure also gives some cross-protection against H5N1.
This preprint from USA (2024-07-13) reports that they were able to show airborne transmission between an infected cow and heifers and mammary transmission between an infected cow and other cows. The cows who got infected via mammary transmission got very sick; the heifers had mild cases. (This could just be because the heifers were young?)
This article from USA (2024-07-16) reports that now five poultry workers from a farm in Colorado have tested positive for H5N1, bringing the total number of infected humans in the US to nine.