Moderna vaccine works against variants but at modest level

Moderna’s Covid-19 vaccine formed neutralizing antibodies against all virus variants first identified in South Africa, India, Nigeria, Uganda, and Angola. However, the neutralizing titers were reduced 2.1 to 8.4 folds against the variants compared to the original strain, the company said.

On Tuesday, Moderna released a new study of sera from people vaccinated with the Moderna’s vaccine, which evaluated the activity of variants of the Covid-19 virus in BioRxiv, a preprint site for biology, before peer review.

Earlier, the company published the results of the analysis on its vaccine’s effect against the Alpha variant (B.1.1.7) first identified in the U.K. and the Beta variant (B.1.351) in South Africa in the letter to the editor in the New England Journal of Medicine on April 15.

Moderna’s Covid-19 vaccine formed neutralizing antibodies against all virus variants, but the neutralizing effect was weaker against variants compared to the ancestral strain, the company said.

The analysis was based on serum samples from eight participants obtained one week after their second dose of the Moderna vaccine in a phase-1 study.

The latest study results include serum neutralization analysis for two versions of the Beta variant (B.1.351) and three lineage variants of the Delta variant (B.1.617) first identified in India.

The results showed that people vaccinated with the Moderna vaccine developed neutralizing titers against all virus variants, including additional versions of the Beta variant (B.1.351) first identified in South Africa, three lineage variants of B.1.617 first identified in India, including the Kappa (B.1.617.1), the Delta variants, the Eta variant (B.1.525) first identified in Nigeria. The A.23.1 and A.VOI.V2 variants were first identified in Uganda and Angola, respectively.

However, the neutralizing titers against the Alpha variant and A.23.1 were minimal compared to those against the ancestral strain D614G.

Also, the neutralizing titers were reduced by 2.1 folds against the Delta variant, 3.2 folds against the Gamma variant, 3.3-3.4 folds against Kappa, and 4.2 folds against Eta. In particular, the researchers found a 7.3 or 8.4-fold reduction in neutralizing titers with the additional versions of the Beta variant, compared to the ancestral strain.

Neutralizing titers against the A.VOI.V2, the variant first identified in Angola, went down 8-fold relative to the ancestral strain. Still, the variant has not been designated as a variant of concern or interest, the company added.

“As we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves. We remain committed to studying emerging variants, generating data, and sharing it as it becomes available,” said Stéphane Bancel, CEO of Moderna. “These new data are encouraging and reinforce our belief that the Moderna vaccine should remain protective against newly detected variants.”

The latest findings show the importance of the vaccination with a vaccine proved as effective, he added.

Moderna said it worked on mRNA-1273.211, a multivalent booster candidate, to respond to evolving virus variants proactively.

The booster candidate, which combines a 50-50 mix of the authorized vaccine mRNA-1273 and mRNA-1273.351, aims to address the ancestral strains.