Cambridge:
Moderna says its COVID-19 vaccine protects against worrisome emerging variants of the coronavirus but it's taking the precaution of testing a possible booster dose against the strain discovered in South Africa.
In Monday's announcement, Moderna CEO Stephane Bancel said the move was out of "an abundance of caution" after preliminary lab tests suggested its shot produced a weaker immune response to that variant.
Vaccine manufacturers have been testing their shots against the mutated strains including two that first emerged in Britain and South Africa. In a study conducted with the National Institutes of Health, Moderna used blood samples from eight vaccine recipients, and some immunized monkeys, in laboratory tests against the mutated viruses.
The vaccine was effective against both variants but researchers found a six-fold drop in levels of "neutralizing antibodies" against the strain from South Africa. Moderna said while the levels still were protective, it has begun developing a booster vaccine targeted to that new strain, called the B.1.351 variant. In addition, Moderna will test if simply giving an extra dose of the original vaccine could be helpful.
Pfizer Inc said on Tuesday that along with partner BioNTech Se it was developing a booster shot to protect against COVID-19 variants.
"We are already laying the groundwork to respond quickly if a variant of SARS-CoV-2 shows evidence of escaping immunity by our vaccine," Pfizer said in an email to Reuters.
However, the company added that studies needed to evaluate the booster shot are yet to be determined in agreement with regulato
Pfizer, which makes a similar COVID-19 vaccine, has previously reported that its shot also appears effective against the strain from Britain. But other research has raised questions about the variant from South Africa.
Meanwhile,a World Health Organization (WHO) panel of experts recommended on Tuesday that the Moderna Covid-19 vaccine be given in two doses at an interval of 28 days, which could be extended under exceptional circumstances to 42 days.
The WHO's Strategic Advisory Group of Experts on Immunization, known as SAGE, advised in a series of recommendations issued after reviewing data that the vaccine not be used on pregnant women unless they are health workers or have conditions putting them at high risk.