To study the impact of the existing vaccine, called mRNA-1273, Moderna took blood samples from eight people who had received two doses of the vaccine, and two primates that had also been immunized.
Moderna said it is also working on a Covid-19 booster shot to protect against a new variant first identified in South Africa. In a news release, they said they will continue to monitor strains and will conduct studies to monitor how effective the vaccine is in the real world. Results from a smaller Novavax study in that country suggests the vaccine does work but not almost as well as it does against the variant from Britain.
But for the South African variant, B.1.351, there was a sixfold reduction in the neutralizing antibody level.
Neutralisation against the virus with the three key mutations present in the South African variant was slightly lower when compared to neutralisation of virus containing the other mutations that were evaluated, the results showed.
De Oliveira said at the moment it does seem like the variant is prevalent in the country.
But at least one of the tests suggested the new variant might be able to elude the body's immune system.
Sera of vaccinated individuates was found to neutralize all three SARS-CoV-2 strains studied, which included the variants that have emerged in the United Kingdom and South Africa.
Novavax said it needs some additional data before it can seek British authorization for the vaccine's use, sometime in the next month or so.
The preliminary findings may help Novavax win authorization for its vaccine in Britain, but the USA government is funding a far larger study that's still recruiting volunteers. Novavax said it's not clear if the Food and Drug Administration will need data from that study, too, before deciding whether to allow USA use.
One mutation in particular - known as E484K and found in the South Africa and Brazil strains but not the one in Britain - has experts particularly anxious about immunity "escape". But the Novavax candidate is made differently than the first shots being used. Scientists extract and purify the protein and then mix in an immune-boosting chemical.