Johnson & Johnson single-dose COVID vaccine is 66% effective, company says

The company plans to file for emergency use authorization in the US in early February.

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Johnson & Johnson on Friday said its single-dose vaccine was 66% effective overall in preventing COVID-19 in its global clinical trial, and 85% effective in preventing severe disease. The trial included nearly 44,000 participants across the US, Latin America and South Africa, and the level of protection varied by region.

"The level of protection against moderate to severe COVID-19 infection was 72% in the United States, 66% in Latin America and 57% in South Africa, 28 days post-vaccination," the company said, adding that the "onset of protection was observed as early as day 14."

Johnson & Johnson said it plans to file for emergency use authorization in the US in early February. It'll likely join the Pfizer and Moderna vaccines, which trials showed to be more than 90% effective, already being given in the US. 

Unlike the Pfizer and Moderna vaccines, the Johnson & Johnson vaccine only requires a single shot. It can also be stored at normal refrigeration temperatures of 35 to 46 degrees Fahrenheit for up to three months, significantly longer than the Pfizer and Moderna vaccines

"Changing the trajectory of the pandemic will require mass vaccination to create herd immunity, and a single-dose regimen with fast onset of protection and ease of delivery and storage provides a potential solution to reaching as many people as possible," said Dr. Mathai Mammen, head of Janssen Research & Development, in a release on Friday.