Seroprevalence
This study from 18 June 2021 found that at the end of the second wave, between 5 and 6% of Canadians had antibodies to COVID-19, up from 2% after the first wave.
Vaccines
This study (done in Ontario) says that Moderna scores best against all the variants, and that Moderna does well against Delta and Pfizer isn’t actually that bad:
| Moderna | Pfizer | AZ | |
| Alpha 1 dose | 83% | 66% | 64% |
| Alpha 2 doses | 92% | 89% | * |
| Beta/Gamma 1 dose | 77% | 60% | 48% |
| Beta/Gamma 2 doses | x | 84% | x |
| Delta 1 dose | 72% | 56% | 67% |
| Delta 2 doses | x | 87% | x |
| Moderna | Pfizer | AZ | |
| Alpha 1 dose | 79% | 80% | 85% |
| Alpha 2 doses | 94% | 95% | x |
| Beta/Gamma 1 dose | 89% | 77% | 83% |
| Beta/Gamma 2 doses | x | 95% | x |
| Delta 1 dose | 96% | 78% | 88% |
| Delta 2 doses | x | x | x |
Here is a screengrab of the original table.
This study from Israel says that Pfizer is only 64% effective against Delta in Israel, even with two doses. (This is different from the 88% efficiency which Pub Health England reports and the 78% which the above Canadian study reports.)
This article calls for using fractional doses to make the limited dose supply go farther, and this study says that using a one-fourth dose of Moderna gives immune responses in test tubes that look about the same as the responses in blood of people who have recovered from COVID-19. (Remember, though, that the mRNA vaccines give better protection than getting the disease.)
Recommended Reading
This article talks about the mental health crisis that did not materialize during the pandemic. While yes, it’s been devastating for some, mostly people… dealt with it. Note: I believe that by “mental health issues”, they mean clinical problems, not just “I feel bad/worn down”. There is obviously a lot of the latter, it just apparently didn’t rise to the level of a clinical issue.
This article talks about vaccine passports.
This is kind of fun: in Chennai, India, some folks decorated an autorickshaw used for mobile vaccinations as a “Vaccine Auto”. Probably awful for people who hate needles!