Novavax Soars After Upbeat Results From Covid Vaccine Trial (4)

A new Covid-19 vaccine from Novavax Inc. was effective in big trials in the U.K. and South Africa, though its protective power appeared to be reduced in South Africa, where a worrisome mutation is prevalent.

The results indicated that another highly potent vaccine could soon be available to help ameliorate the pandemic, in addition to existing vaccines from Pfizer Inc., Moderna Inc., and AstraZeneca Plc that are authorized in various countries. But the South Africa results also suggested that the virus is starting to mutate in ways that could make vaccines less effective over time.

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