2021-08-18 General


There has been a lot of discussing recently about waning effectiveness of vaccines. I want to editorialize for a moment: you expect vaccine effectiveness against infection to appear worse in real life than in the studies, and to appear worse over time.

  • More time to get infected. If the vaccine is 95% effective over the course of a study, then given infinite time, every single person (vaccinated and unvaccinated) will get infected, leading to a VE of zero.
  • Vaccinated people are more likely to engage in risky behaviour than those who know there is only a 50-50 chance they are protected.
  • Unvaccinated people are much more likely to catch COVID-19, and some of those cases will be asymptomatic, so nobody will realize they will have gotten it. Those people will have some immunity, so it will look like the advantage vaccinated people have will go down.

The above are separate from antibody waning. This is well known and understood: levels of antibodies in your blood drop. They can be regenerated, but it takes a little time, so a vaccine might not keep you from getting infected. Note that the effectiveness against severe illness does not appear to be waning significantly, which is what you’d expect if a strong immune response shows up a few days later.

This US CDC report says that vaccine effectiveness in New York dropped from 91.7% to 79.8%.

This US CDC report says that vaccine effectiveness in nursing homes dropped from 74.7% in March/May to 53.1% in June/July (when Delta showed up).

This US CDC report (yes, three CDC reports dropped today) says that vaccine effectiveness against hospitalization only dropped a measly 2% in 24 weeks, from 86% to 84%.

There are multiple jurisdictions which say that you only get one dose if you also have an infection because a second dose doesn’t change much. This preprint says that if people who get infected after their first dose but before their bake-in time has finished have responses similar to people who have never been vaccinated, and should get a second dose.

This article says that people who got SARS and then COVID-19 vaccines have AWESOME antibodies.

This preprint says that vaccine effectiveness against infection is lower against Delta than previous variants, and decreases over time.


This tweet (from an Ontario doctor) says that the risk of hospitalization for kids under ten years old is 2.75 times higher than for other variants.


Why are kids more resistant to COVID-19? In addition people having or not having genes, there’s also something called “gene expression” which is basically how much the gene is turned on. This paper says that the sensor cells in kids are expressed at a higher level than adults. Think of it like their watchmen have been chugging Red Bulls while the adult watchmen have been drinking chamomile tea.


This is yet another article which shows that convalescent plasma doesn’t help people recover from COVID-19. It’s strange, you would think that it would, but there have been quite a few studies, all saying nope nope nope.

Recommended Reading

This article talks about vaccine effectiveness waning.

This article is about lipid nanoparticles, which envelop the mRNAs to smuggle it past the body’s immune system. (And it has Canadian content! And drama!)