Last time we learned that a new strain of the SARS-CoV-2 virus has emerged in London and southeast England. This variant strain, called “VOC 202012/01” or “B.1.1.7” is more infectious than the standard SARS-CoV-2. It has quickly spread to other parts of Europe, and its presence is now reported in Canada and the United States. At least two other distinct variants are reported in South Africa and Nigeria. How do we keep track of these variants, and what does their rapid spread mean?
The variants are named by adding suffixes of letters and numbers to help keep the many cataloged mutations straight. Two different systems may be used. For example, the South African variant is labeled “501Y.V2”, but it is also known as “B.1.351”. The Nigerian variant is called as “B.1.207”. Neither of these has been labeled a “variant of concern”.
A “variant of concern” is a strain is associated with differing clinical features such as greater disease severity or faster spread. “Variants of concern” will have the letters “VOC” in their name. So far, the first and only “variant of concern” is VOC 202012/01, the variant identified in London which has now spread into Europe, Canada, and the United States.
While none of the variants identified so far seem to evade detection by the PCR tests generally available to the public, these tests will not tell you whether a detected virus is one of the variants. Specialized sequencing is required to identify a virus as a variant. This testing is conducted on a regular but limited basis by the CDC, state and local health departments, and various universities.
The CDC is watching the evolution of variants closely. The concern is that increasing numbers of variants may change the way the virus spreads, may reduce detection by current tests, may create resistance to drugs such as monoclonal antibodies, or may produce a strain that evades immunity caused by vaccine or previous infection. We will watch too. As the “variant of concern” spreads into the United States, remember what keeps us safe: mask up, keep apart, and isolate when exposed.
