Variant Roulette (Evolution and Immunity Escape)

Mito · Jul 22, 2021

”The reason public health authorities did not talk about evolutionary escape of variants six or ten or fifteen months ago is that, generally speaking, that conversation does not favor the logic of a mass vaccination program in the middle of a pandemic.

To make this point more clear, let us examine the specifics of the variants that have spread and caused trouble.

The Alpha variant emerged in the UK in October, which was when Oxford-AstraZeneca was holding vaccine trials there.
The Beta variant emerged in South Africa, and was first detected in December, 2020, at the tail end of trial periods for both Oxford-AstraZeneca and Pfizer vaccines. This variant carries three mutations in the spike protein.
The Gamma variant was first detected in Japan, but soon after in Brazil, making the origin a little harder to determine. But since Japan has had far lower viral spread than Brazil, it makes the most sense that Brazil was the source. Both Oxford-AstraZeneca and Pfizer trialed their vaccines in Brazil.
The Delta variant was first detected in India in October, 2020. India hosted numerous vaccine trials including one for Oxford-AstraZeneca and one for Covishield.

It is noteworthy that variants of interest did not emerge during the early stages of the pandemic, despite mass spread of SARS-CoV-2 around the globe. That's a pretty huge sample size of unvaccinated people. But those that have emerged did so in geographies where vaccine trials were held---that is several variants from a far smaller genetic pool.”