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Covid-19 Vaccine Shown Active Against Variants



25 Jan. 2021. Moderna Inc., developer of a vaccine to prevent Covid-19 disease, says lab test results show antibodies from the vaccine neutralize two recently found viral mutations. The Moderna vaccine, code-named mRNA-1273, is one of two vaccines with an emergency use authorization from the Food and Drug Administration for protecting against Covid-19 disease symptoms.

Moderna tested blood samples from people already vaccinated with mRNA-1273 against analogs of two variations from the original SARS-CoV-2 virus found in the United Kingdom and South Africa, known respectively as B.1.1.7 and B.1.351. The biotechnology company, in Cambridge, Massachusetts posted the findings on its web site and in a manuscript on the pre-publication server bioRxiv. The reports are not peer-reviewed.

Appearance of these two mutations led to recent concerns about the ability of currently authorized vaccines to protect against new infections, since the vaccines produce antibodies that target the protein chemistry of the spike on the coronavirus that penetrates cells and begins the infection process. Adding to the concerns is the reported higher transmissibility of these variations, making it easier to get infected, as well as higher viral loads they produce.

Moderna conducted its lab tests with the Vaccine Research Center at National Institute of Allergy and Infectious diseases, or NIAID, part of National Institutes of Health. The mRNA-1273 vaccine is administered in two doses, given 28 days apart. Blood serum samples from eight people and two monkeys receiving both doses contain antibodies in concentrations that neutralize the U.K. variation, B.1.1.7, at a similar rate as the the original virus.

New vaccine booster candidate

For the South African variant B.1.351, however, antibody concentrations produced by the vaccine are about 1/6th less effective at neutralizing the virus. Nonetheless, says Moderna, the reduced concentrations or titers still appear sufficient for protecting against the disease.

The company says it started work on additional steps to protect against these emerging threats. Moderna plans to test an mRNA-1273 booster dose to produce higher antibody concentrations to combat new SARS-CoV-2 strains. And the company is developing a variation of its vaccine code-named mRNA-1273.351 specifically addressing the South African mutation. Preclinical work on mRNA-1273.351 is expected to begin soon, followed by an early-stage clinical trial.

“We are encouraged by these new data, which reinforce our confidence that the Moderna Covid-19 vaccine should be protective against these newly detected variants,” says Stéphane Bancel, CEO of Moderna in a company statement. “Out of an abundance of caution and leveraging the flexibility of our mRNA platform, 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.”

As reported by Science & Enterprise earlier this month, antibodies produced by the vaccine brand-named Comirnaty, made by BioNTech and drug maker Pfizer, also emergency-authorized by FDA, generates antibodies that in lab tests appear to act against the U.K. and South African variants. In those tests, antibodies from 20 participants receiving two doses of the vaccine from a late-stage clinical trial produced antibodies that neutralize synthetic viruses with a genetic property found in both mutations, at the same rate as the original virus.

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Disclosure: The author owns shares in Pfizer.

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