Moderna vax protects against variants but the drugmaker is working on a booster, just in case

Jan. 25, 2021

Moderna says its COVID-19 vaccine retains neutralizing activity against variants first identified in the U.K. and South Africa, but "out of an abundance of caution" the drugmaker is launching a clinical program to boost immunity to emerging variants.

According to results from in vitro neutralization studies, the vaccine produced neutralizing titers against all key emerging variants tested, including B.1.1.7 and B.1.351, first identified in the UK and Republic of South Africa, respectively. The study showed no significant impact on neutralizing titers against the British variant, B.1.1.7, relative to prior variants. But with the South African variant (B.1.351), there was a sixfold reduction in neutralizing titers. While this could mean the vaccine is less effective against the variant, according to Moderna, "neutralizing titer levels with B.1.351 remain above levels that are expected to be protective."

In order to proactively address the pandemic as the virus continues to evolve, Moderna has announced a new clinical strategy. First, the company will test an additional booster dose of its COVID-19 vaccine (mRNA-1273) to study the ability to further increase neutralizing titers against emerging strains beyond the existing primary vaccination series. Second, the drugmaker is advancing an emerging variant booster candidate (mRNA-1273.351) against the B.1.351 variant first identified in the Republic of South Africa.

Read the press release