What We Know About the New Coronavirus Variant

There’s still plenty of unknowns, but here’s a few takeaways

Andy Slavitt
Medium Coronavirus Blog
4 min readJan 5, 2021


Credit: National Institute of Allergy and Infectious Diseases, NIH

Here’s the best we know about the impact of the South African strain, and the impact on the vaccine from lots of conversations I’ve had with experts.

To begin with, we are back to assuming a modest and humble position that there’s a lot we don’t know, just like we were early on. When we are in the “there’s a lot we don’t know” stage, I like to air on the side of caution. Risking being wrong is no reason not to act. Acting wisely with the best we know can save the most lives.

What we know about the most significant variances is that they are more infectious. That’s why we noticed them. Important and subtle point I keep hearing: The virus is mutating in less visible and measurable ways that we can’t see as easily and therefore can’t address.

As we vaccinate more people, these other evolutionary mutations are likely to become more visible. But we have to deal with the ones in front of us first. The one first spotted in South Africa has mutated several things at once and there is more nervousness about the vaccines here.

Because we don’t know how much of the virus we missed, we could be seeing a jump in cases compared to no mutations (lowest line) anywhere from the green (we haven’t missed much) to blue (there is a lot more than we know).

So if you look at the curve on the right, the space under the curve between the colored lines and the low lines represents excess deaths from the mutation. It’s a big range — anywhere from 20,000 to 260,000 additional deaths — assuming our current projected rate of vaccinations.

There are many simplifying assumptions here but the magnitude is worth understanding.

Next question — why? Isn’t this not supposed to be more deadly? Think of the virus as being easier to attach to a cell. One way to think about it is if today it normally requires 1,000 particles to cause infectiousness, the new strain requires about 60% fewer or 400 particles.