ACovid-19 vaccine from Novavax proved nearly 90% effective in preliminary results from a key clinical trial in the United Kingdom, the company said, but in a separate trial appeared far less effective against a new variant of the coronavirus that was first identified in South Africa. In its 15,000-volunteer U.K. trial, Novavax said, the vaccine prevented nine in 10 cases, including against a new strain of the virus that is circulating there. But in a 4,400-volunteer study in South Africa, the vaccine proved only 49% effective. In the 94% of the study population that did not have HIV, the efficacy was 60%. In the U.K. trial, Novavax observed 62 cases of symptomatic Covid-19, with 56 in the placebo group and six among volunteers who got the vaccine. One patient on placebo developed severe Covid-19, compared with zero in the vaccine group. The company provided few details on the vaccine’s safety, saying only that the serious side effects were rare and balanced between the studies’ vaccine and placebo groups.

 

Maksim Tkachenko

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