COVID-19
Long COVID
This preprint from USA (2026-10-16) reports that a subset of people with Long COVID have activated T cells targeted to COVID-19 which are activated — which before has always (or maybe almost always?) meant that there was some level of virus in the body that was activating it. In addition, their T cells weren’t working very well, a sign of “exhaustion”.
Finally, they found that T cells which target to the Epstein-Barr Virus were also disproportionately activated, suggesting that COVID-19 reactivated EBV.
There have been a lot of studies trying to find where SARS-CoV-2 might be hiding, or other ways of proving that Long COVID comes from reservoirs of virus, but those have all been inconclusive at best. For this study, they didn’t look for virus, but for T cells which were associated with the virus — sort of like looking for a burglar not by looking for a human, but by looking for footprints.
Pathology
This paper from Denmark (2026-10-20) reports that COVID-19 severity depends more on your environment than your genes. In what I think was a very clever study, they looked at twins, their spouses, and a matched cohort. They found that the risk of being hospitalized for a COVID-19 infection was much higher if your spouse was hospitalized than if your twin was hospitalized for an infection. (I presume that means hospitalized when infected. It would be pretty stupid if you expected someone who didn’t live with person X to get infected at the exact same time as person X.)
I assume that if spouses both get sick, they get sick with the same strain, so it is possible that we’re just seeing that people who get the same exact strain are going to respond the same. However, it seems more likely to me — given all I’ve seen about how important the gut biome is to disease outcome — that people who eat together have similar biomes and hence have similar gut biomes.
Influenza
Testing
This page says that FluWatchers is looking for more volunteers. Basically, every week, you fill out a questionnaire which asks if you (or anyone in your household) had a fever or cough that week. It’s part of the regular influenza surveillance and very valuable. I encourage you to sign up. (I did!)
Measles
Transmission
According to the Government of Canada Measles and Rubella Monitoring Report (updated 2026-10-19), in the week ending 10 October 2026, the following jurisdictions had the following number of new measles cases:
- Canada: 3;
- Ontario: 2;
- Quebec: 1.