The Latest about Variants

The CDC recently released new information about the variants of SARS-CoV-2, updating information previously released.

Although SARS-CoV-2 mutates frequently, about once every two weeks, most mutations do not result in a clinically different virus.  However, three variants have emerged which are being watched closely.

B.1.1.7 is the first variant of concern which emerged in the UK last December and is now present in at least 70 countries, including the United States.  This variant is associated with a fifty percent higher transmission rate, which means it may soon be the dominant form of the virus.  There is emerging data that suggests this form of the virus is also associated with a higher death rate.

B.1.351 emerged in South Africa and has spread to other countries, including the United States.  There is data that suggests that the Moderna mRNA-1273 vaccine currently used in the US may be less effective against this variant.

P.1 has been found in Japan and Brazil.  As of late January, this variant is known to exist in the United States.  There is data suggesting this variant may be less susceptible to immunity acquired either by previous infection or by vaccination.

All three variants are concerning because of mutations in the spike proteins in the virus.  These proteins are significant because they are responsible for the binding of virus to cells in the back of the nose, the first step in infection.  They are also significant because antibodies in the human immune system work by recognizing these spike proteins.  Whether these antibodies come from natural immunity (i.e., previous infection), induced immunity (i.e., vaccination) or convalescent plasma, altered spike proteins may allow viral particles to slip past this line of protection.

Since we’ve talked a lot about vaccination recently, now may be the time to discuss how COVID vaccines work.  We will pick up there next time.