2021-07-07 General


A few days ago, there was a Israeli Ministry of Health report saying that Pfizer was only 64% effective against the Delta strain, which was far lower than other studies had found. It looks like the study in Israel was against all infection, including asymptomatic infection, while the others were against symptomatic infection.

That aligns with this article, which says that a study in Singapore found that Pfizer was 69% effective against all infection and “between 80 and 90 per cent” for symptomatic infection.

There has been speculation that the AZ clotting issues are a result of AZ getting into the bloodstream. (Injections into the muscle drain into the lymph system, not the bloodstream.) One theory is that very rarely, the needle aimed at the deltoid hits a blood vessel. Another theory is that the spliceosome in the nucleus makes a copying error which eliminates the membrane anchor, allowing the spike protein to get into the cell.

Today, this study was released. It looked at what happens if you inject mice with AZ intravenously instead of intramuscularly, and found antibodies which bound to platelets.


This study found that 77% of COVID-19 patients had zero symptoms after one year. (Ed: This seems out of line with other studies — my gut is that it’s about 30%.)

On the other hand, this study said that 50% of COVID-19 patients had symptoms after 12 weeks.


Statistics Canada did a seroprevalence study, collecting data from November 2020 to April 2021.

Note that because the study collected samples over a long period, at a time when case counts were increasing (sometimes rapidly), they are a little hard to interpret. You can’t give a specific date when these numbers held, so you can’t compare these numbers to the number of confirmed cases on any given date.

We also don’t know if the samples for each category were taken at the same time. If all the BC samples were taken in November 2020 and all the samples from Alberta were taken in April 2021, then obviously the BC numbers will be lower.

Hopefully the samples were taken at more-or-less the same time for all the categories, so hopefully it is reasonable to compare BC to Alberta (for example).

It’s also useful to get a ballpark idea. We can be pretty sure that as of April, at least, less than 10% of Canadians had gotten COVID-19.

totalfrom infectionfrom vax
Atlantic provinces1.3%0.5%0.8%
Under 20 y/o~3.4%3.4%~0.0%
20-59 y/o4.5%2.9%1.6%
Over 592.1%1.4%0.7%
Visible minorities4.8%4.3%0.5%


A preprint which I missed on 29 June 2021 said that after vaccination, IgG and antibody levels in the blood are waaay higher in blood than saliva. This newsletter wonders if that’s why vaccination does keep you from getting badly sick from Delta, but doesn’t do nearly as good a job at keeping you from getting infected at all.

This article reports on a study into perceptions of risk. It turns out that people think that activities they consider moral (e.g. going to church) are safer than activities they consider less moral (e.g. going to the beach). This helps to explain why people got bent about throngs of people at the beach (which were probably quite safe, actually).


This study looked at data collected from wearables and found that the heart rates were very different during recovery from COVID-19 than from recovery from other respiratory illnesses:


This case study of three people with AZ-related blood clotting suggests that exchanging their blood plasma with donor plasma can help a lot.

Unintended Consequences

I have seen a number of articles which have said that the mental health impact of the pandemic has been lower than expected. For example, there hasn’t been a rush of adult suicides.

However, apparently people are drinking more. This study says that Alcohol-Associated Liver Disease went up by 62%.

Recommended Reading

This article is interviews we three people giving retrospectives on the pandemic: what did we learn, what should we do better next time? It was more interesting and provocative than I expected: Zoom bad, one-size-fits-all-mitigation bad, closing schools bad, etc.

This article talks about COVID-19 and schools.

There is a neat interactive graph showing how Treatment A compares to Treatment B. It’s not actually very informative at the moment (except to say that there aren’t very many good treatments), but they say that they will keep it updated as more results come in.

This essay talks about vaccinating kids. One thing it points out is that the age structure in low-income countries can be vastly different from in high-income countries. In wealthy countries, the average share of the population which is under 15 is 16%, but in low-income countries the average is 42%.