Laboratory trials of the Novavax vaccine in the UK

Novavax Inc. said Thursday that its COVID-19 vaccine appears 89% effective based on early findings from a British study and that it also seems to work - though not as well - against new mutated versions of the virus circulating in Britain and South Africa.

The announcement comes amid worry about whether a variety of vaccines being rolled out around the world will be strong enough to protect against worrisome new variants, as the world desperately needs new types of shots to boost scarce supplies.

The study of 15,000 people in Britain is still underway.

But an interim analysis found 62 participants so far have been diagnosed with COVID-19 – only six of them in the group that got the vaccine and the rest who received dummy shots.

Novavax said their data suggest the vaccine is nearly 96% effective against the older coronavirus and nearly 86% effective against the U.K. variant.

Scientists have been even more worried about a variant first discovered in South Africa that carries different mutations.

Results from a smaller Novavax study in that country suggests the vaccine does work but not nearly as well as it does against the variant from Britain.