What is a Sarbecovirus and How Can it Help Protect Us Against Variants?

September 14, 2021

SARS-CoV-2 is a subspecies of virus within the subgenus of sarbecovirus, which are all respiratory viruses. The easiest way to picture the lineage is by thinking of a family tree with a grandparent, parent, and kids.

Here we can see that the “grandparent” is the overarching genus of beta coronaviruses (one of four types of coronaviruses, which include alpha-, gamma-, and delta-). Following the family tree, we can think of the sarbecoviruses as being the “parent” and under that we have the group of “kids” which are the types of coronaviruses we have been battling in recent years (SARS in early 2000, MERS in the mid-2010s, and now COVID-19). They may all be in the same family tree and share a good amount of their genetic material, but as we have learned through the evolution of SARS-CoV-2 variants, they are not all identical. We know this because having COVID-19 does not mean you are protected against SARS or MERS, just as having a SARS or MERS infection does not protect you against COVID-19.

In a recent Nature article, researchers gave a COVID vaccine to a group of individuals who had previously experienced a MERS and SARS infection. They found that the subjects were not only able to develop antibodies against those viruses, but also another 8-10 of the virus’ variants. This led the team to explore the idea of developing a vaccine at the “parent” level as opposed to creating multiple vaccines against all the “kids” and their variants. The authors concluded their study by stating “we anticipate [this] data will guide future efforts to develop vaccines that overcome the emergence of SARS-CoV-2 variants and that are effective against all sarbecoviruses”. This means that if we focus on developing antibodies and creating vaccines one level up, they may provide protection against all the subtypes of coronaviruses that we are seeing now and may see in the future.