What is a virus variant, and why are scientists concerned about them? A variant is a small change in the genetic material within the virus, the ribonucleic acid (RNA), making it different than the original source virus. This happens with viruses all the time as they reproduce and move from host to host, gaining small, usually insignificant, differences. When a virus gains a variation that makes it more transmissible, causes more significant illness, or more resistant to vaccines, it becomes a variant of concern.
In the US there are five variants of the SARS-Cov2 virus (the virus that causes the disease COVID-19) that are being closely monitored:
B.1.1.7: This variant was first detected in the United States in December 2020. It was initially detected in the United Kingdom and is often referred to as the “UK variant”.
B.1.351: This variant was first detected in the United States at the end of January 2021. It was initially detected in South Africa in December 2020.
P.1: This variant was first detected in the United States in January 2021. P.1 was initially identified in travelers from Brazil, who were tested during routine screening at an airport in Japan, in early January.
B.1.427 and B.1.429: These two variants were first identified in California in February 2021.
These variants seem to spread more easily and quickly than other variants, with some showing increased severity of symptoms in younger populations. The reasons for the increased infection are not fully studied, but it likely takes a much smaller viral dose (number of viral particles) for infection, so less contact is needed to spread the virus. So far, studies have shown that current vaccinations in the US are effective against these variants, but should vaccines prove less effective against one or more variants the composition can be updated and delivered as a booster shot. Getting vaccinated is the most effective way to reach herd immunity and limit the opportunities for dangerous variants to emerge.
Reference:
https://www.cdc.gov/coronavirus/2019-ncov/variants/variant.html