2021-07-16 General


This preprint found that antibody levels wane over time, moreso for AZ than Pfizer, and less so in women. (BNT162b2 is Pfizer; ChAdOx1 is AZ.)

Reminder: antibodies are only one element of protection, and the body should be able make more if the B-cells are well-trained.

This article says that vaccines for kids 6 to 11 years old probably won’t come until midwinter.


There have been a few Delta case studies which have come out recently:

  • A wedding: Two fully-vaxxed people who had gotten vaxxed ten days earlier tested negative and went to a wedding with 90 other fully-vaxxed people. The first two later tested positive; one died. Of the other 90 people, four got sick and one died was hospitalized.
  • A pool party: Eleven health care workers who were at a pool party, eight of whom were fully vaccinated, tested positive afterwards. They all had mild symptoms, but fortunately (as health care workers) knew to take them seriously. It is not clear how many people were at the pool party and if it was indoors, outdoors, or mixed.
  • A quarantine hotel: In Australia, an outbreak has been traced (via whole-genome sequencing) to a man who was in quarantine. They cannot figure out how he passed the virus.
  • A Navy flotilla: UK sailors went partying in Cypress, then went back to their ships. At least 100 sailors on the aircraft carrier HMS Queen Elizabeth got sick. All the crew was fully vaccinated. Wikipedia says that it has a capacity of 1600, but it looks like normal operation is more like 930.

I want to reminder you that the vaccines are quite effective — 95% of the wedding guests and about 89% of the HMS Queen Elizabeth did not get sick. However, “highly effective” is not the same as “perfect”.

According to this article (in Dutch, use Google Translate) thousand people “proven negative” apparently got COVID at an outdoor music festival in the Netherlands. They had to be fully vaccinated, infected and recovered, or show a negative test. It is possible that they got infected in the 40 hours between their negative test and the start of the festival; it’s possible that they caught it outside the festival — presumably they went to restaurants and stayed at hotels or took trains back home; it’s possible that they forged their proof. Still, it is worrying.

Mitigation Measures

This article says that, if things keep going the way they are going:

  • Fully-vaccinated Americans will be allowed into Canada in mid-August for non-essential travel.
  • Fully-vaccinated people from anywhere will be allowed into Canada in early September for non-essential travel.

It isn’t clear if they will need to show a negative test at the border and take a test at the border, like returning Canadians now do. They also didn’t say anything about changes to the current policy for Canadians.