How Worried Should We Be About the Delta Variant?
The virus that causes COVID-19 has been a successful one from an evolutionary perspective, getting to see the world and expanding its little family tree. (Its been successful from its point of view; not so much from ours.) This means that variants of the virus have popped up in several different locations, and some are variants of concern that are more transmissible or potentially could be more harmful. Lets do a rundown of the ones you should know about. When we last wrote about the variants, they had hard-to-remember code names, and scientists often talked about the codes for the mutations they contained, which made for a lot of confusion as we tried to keep straight which was which. As a result, people often used geographical nicknames (eg, the South Africa variant,) which is problematic on many levels  not least because viruses travel, so any place name will be quickly out-of-date. COVID variants of concern  The variants have now been renamed after Greek letters, to make them easier to talk about and keep track of. The first four are considered variants of concern, which means they may be more transmissible, more virulent, or that they may be better at evading public health measures than the other versions of the virus. There are those four:  Alpha  The Alpha variant, B.1.1.7, was first detected in the U.K. in September 2020. It was among the first variants to make headlines, and its estimated to be 50% more transmissible than previous versions of the virus. It is currently the dominant strain in the US. Fortunately, people who are vaccinated with Pfizer or Moderna or who previously had another strain of COVID seem to be able to fight it off just fine. Tests with other vaccines have not yet been published, but the data we have is reassuring. For example, the study on the Pfizer vaccine found that it was 90% effective against this variant. Beta  The Beta variant, B.1.351, was first detected in South Africa in May 2020. It was associated with higher levels of hospitalisation and death than original COVID. The Pfizer vaccines efficacy against Beta is just 75%, but that jumps up to 97.4% when youre looking at severe or fatal cases, so the vaccine is still very helpful. Gamma  The Gamma variant, P.1, was first detected in Brazil in November 2020. Gamma is more transmissible than original COVID, but less so than Alpha. Previous infection with COVID may provide less protection from Gamma than from other strains. Fortunately, its not spreading as fast as other variants. Studies in areas with both Alpha and Gamma found that Alpha tended to become more prevalent over time, while Gamma did not. Delta  The Delta variant, B.1.617.2, was first detected in India in October 2020. In April of this year it was considered a variant of interest  more on that category below  and was upgraded to a variant of concern in May. This is the variant currently seen as the most concerning. Delta is more transmissible than the other variants (even compared to Alpha), and it may be more likely to cause severe illness. The Pfizer vaccine seems to be slightly less effective against Delta than Alpha, but its still strongly protective once youve gotten both doses. Variants of Interest  Variants of interest arent as big a deal as variants of concern  yet. They have mutations that are established or suspected to cause the virus to behave differently, and to be recognised, they also have to be spreading in the community or otherwise be judged to be of interest to scientists (so an isolated virus in the lab or in a handful of isolated cases may not qualify). So far, none of the variants are drastically different from original COVID; our vaccines and public health measures seem to work well against the variants, even if some may be slightly less effective. These arent game changers, just reasons to be a little extra cautious. Scientists are paying close attention to how these variants spread and how well protected we are against them. For now, its still best to get vaccinated if you can, and wear masks and observe other public health measures. Besides the variants of interest and variants of concern, there is another category, according to the CDC: variants of high consequence. This would be used for any variants that can dodge diagnostic tests, significantly reduce vaccine effectiveness, or result in much more serious disease. So far, none of the COVID variants qualify.