Moderna vaccine booster planned after mutant COVID-19 tests get ominous results

Chris Davies - Jan 25, 2021, 2:32pm CST
Moderna vaccine booster planned after mutant COVID-19 tests get ominous results

Moderna is preparing a booster jab for its COVID-19 vaccine, after more virulent strains of the coronavirus were identified in the UK and South Africa. The pharmaceutical company confirmed today that its research suggests the existing vaccine already being deployed around the world may not be as effective at handling all of the newly-emerged mutations of COVID-19.

So far, two of those mutations have been identified and studied. SARS-CoV-2 B.1.1.7 was first recorded in the UK in September 2020, while a B.1.351 variant was identified in South Africa. Both have proved to be fast-spreading, accelerating out of their initial countries of discovery, “and are associated with increased transmission and a higher viral burden after infection,” Moderna says.

The big question was whether the existing Moderna COVID-19 Vaccine (mRNA-1273) would be sufficient to give the same protection against these new types of virus as it was for the original. The pharma company’s study indicates that, while the variant identified in the UK shows similar results with the drug, the South African variant does not.

The research focused on what are known as neutralizing antibody titers. They’re left behind by the vaccination, and are what prevent infection from the actual COVID-19 virus. In the case of the B.1.1.7 variant, “the study showed no significant impact on neutralizing titers against the B.1.1.7 variant relative to prior variants,” Moderna says.

However, the B.1.351 variant was a different matter. Although the existing vaccination still produces titers that remain above the levels indicated to protect against COVID-19 infection, they were approximately 6x lower compared to prior variants.

“While the Company expects these levels of neutralizing antibodies to be protective … these lower titers may suggest a potential risk of earlier waning of immunity to the new B.1.351 strains,” Moderna cautions. In short, even if you’re immune by vaccination to the originally-identified COVID-19 virus, that doesn’t mean you’ll automatically be immune to future variants, or indeed immune for as long.

“Out of an abundance of caution and leveraging the flexibility of our mRNA platform,” Stéphane Bancel, CEO of Moderna said today, “we are advancing an emerging variant booster candidate against the variant first identified in the Republic of South Africa into the clinic to determine if it will be more effective to boost titers against this and potentially future variants.”

Moderna plans to test if a third dose beyond the standard two – administered one month apart – increases neutralizing titers against emerging strains. It’s also working on an emerging variant booster candidate (mRNA-1273.351) focused specifically on the B.1.351 mutation first identified in South Africa. Tests of that are being moved into preclinical studies and a Phase 1 study in the US.


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