Multiple studies now confirm B.1.1.7 is significantly more infectious.

I was pretty skeptical when the UK announced that they thought that the B.1.1.7 variant was more contagious. They did not have any data showing increased transmission rates. But now multiple countries have done the experiment, showing that people living with someone who has this variant are more likely to catch it, as compared to other variants in the country at the time.

For comparison, we also have similar studies done earlier in the pandemic, that showed that if someone you live with got covid, you have about a 20% chance of catching it from them.

In Norway, 42% of those living with someone who had the B.1.1.7 variant caught it. By comparison, 27% of those living with someone with another variant caught it.

In Denmark, 38% of those living with someone who had B.1.1.7 and 27% of those living with someone who had a different variant caught it.

A study done in San Francisco compared "West coast" variants to all others and found 36% of those in households with west coast variants vs 29% with other variants caught them. These are not exactly the same as the B.1.1.7, but include some of the same mutations.

So it's clear at this point that the virus is becoming more contagious. That's bad because a faster spread rate means more people get exposed in a given amount of time, and there are a lot of people out there with a false sense of security because they haven't gotten it yet. It also means that we will need a greater percentage of the population to have immunity in order to get to herd immunity in the background of normal life.

Remember, though, that the vaccines do work against the B.1.1.7 variant, and at this point vaccination is going well enough in the US that this variant shouldn't pose a massive problem. In other countries, though, it definitely could. Worldwide, I wouldn't be surprised if there were more covid deaths in 2021 than 2020, just because of how quickly the variants can move through the population.

A bit of a silver lining is that a virus with a faster spread rate is more likely to get the population to a point where almost everyone has immunity at the same time. The older variant moved slow enough that we might have ended up with a situation where one person gets immunity, then four months later that immunity has worn off, but the virus is still slowly circulating, so that they get it again. Still, the extra deaths in places where the variants are arriving before the vaccines are a pretty high price to pay for that.

Link to study in Denmark:
https://www.medrxiv.org/content/10.1101/2021.04.16.21255459v1

Link to study in Sweden:
https://www.medrxiv.org/content/10.1101/2021.03.29.21254122v1.full.pdf

Link to study in SF:
https://www.medrxiv.org/content/10.1101/2021.03.01.21252705v1.full.pdf

*Usually by mutation they mean a point mutation like E484K. The variants are different lineages that are accumulating mutations and as they do, they get different names. The Brazil P.1 is called that because they didn't want to write out B.1.1.28.1, because it would be too many digits. But all of the variants of concern have a lot of overlap in what mutations they actually have.

The significance is that it appears to reduce the ability of antibodies from the older variants to neutralize the virus in the lab. Although the Pfizer vaccine seems to work fine in SA, it might wear off faster for the variants with that mutation.