Moderna Inc. said Monday its Covid-19 vaccine appeared to be protective against emerging variants of the coronavirus in laboratory tests, but as a precaution it will start testing whether a booster shot improves immune responses and is developing a new vaccine targeting the strain first identified in South Africa.
The company said its vaccine produced immune-system agents known as neutralizing antibodies against emerging virus variants tested, including strains first identified in the U.K. and South Africa.
These new strains appear to spread more easily from person to person, and there are signs that the U.K. variant is more deadly than earlier forms of the virus.
Moderna said its vaccine induced antibody production against the strain first identified in the U.K., known as B.1.1.7, at levels comparable to prior variants. Yet antibodies decreased sixfold against the strain first identified in South Africa, known as B.1.351.
Even with the decrease, Moderna said, the vaccine-induced antibody response against the B.1.35 variant remained above levels that are expected to be protective. The company said it expects its standard, two-dose vaccine to be protective against the emerging strains to date.
