There are at least three emerging variants of SARS-CoV-2 coronavirus that are worth paying close attention to (1). These are commonly referred to as “the UK variant”, “the South African variant”, and “the Brazilian variant” after their countries of origin. Some of the residents of the UK, South Africa, and Brazil aren’t too happy with those names, but they’re easier to remember and far more descriptive than B.1.1.7, B.1.351, and P.1. Each of these variants has accumulated several mutations that distinguish it in important ways from the original virus that arose in China.

The UK variant (B.1.1.7) is probably the most concerning of the three. Not only is it 35%-45% more transmissible (2), but early reports suggest that it may also be more lethal. It is expected that this strain will be the most dominant one in the US by early summer. This has led to some epidemiologists pushing for a ramped-up goal of herd immunity through vaccination by May. On the bright side, the currently approved vaccines don’t appear to have reduced efficacy to the UK variant.

That cannot be said of the South African variant (B.1.351), which has multiple key mutations to the infamous “spike protein” that change its structure. The reason that’s a problem is that the spike protein is the target of antibodies produced in response to the virus or vaccine. Because the spike proteins look so different, the immune system of a vaccinated or previously infected person is less likely to recognize it. The AstraZeneca vaccine doesn’t appear to be very effective at reducing mild to moderate cases of COVID-19 for this variant, causing South Africa (where this variant is 90% of new cases) to put the rollout of this vaccine on hold (3). It does, however, appear to be effective at preventing severe cases of COVID-19, so even with this strain the vaccine is an important tool.

South America has seen a recent surge in coronavirus cases corresponding with the spread of the Brazilian variant (P.1). Like the South African variant, there are several mutations to the spike protein that may reduce the effectiveness of the immune response, since antigens may not recognize the variant. There is concern that some of the current Amazonian surge in cases may be due to increased transmissibility and/or reinfection with the Brazilian variant (4).

With these new variants spreading in the US, it is more important than ever to follow CDC guidelines in building more robust mitigation layers including masks, hygiene, social distancing, ventilation, sanitation, and testing.

1Emerging SARS-CoV-2 Variants

2UK coronavirus variant spreading ‘rapidly’ through US, study finds

3Covid: South Africa halts AstraZeneca vaccine rollout over new variant

4Spike E484K mutation in the first SARS-CoV-2 reinfection case confirmed in Brazil, 2020

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