One Bavarian Nordic Shot 58% Effective Against Mpox, Study Shows

  • Study was conducted in Canada for about four months in 2022
  • High vaccine coverage may blunt mpox rebound, scientists say

A health worker administers a dose of the Bavarian Nordic A/S Jynneos vaccine in West Hollywood, California, in 2022. 

Photographer: Jill Connelly/Bloomberg
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Bavarian Nordic A/S’s smallpox vaccine was moderately effective in preventing mpox infection after a single dose, according to a study in Ontario, Canada, where the shot probably helped curb a 2022 outbreak.

One vaccination provided about 58% protection against mpox infection, researchers found in the study. It was conducted from mid-June to late October 2022 among gay and bisexual men — the group most affected during a global outbreak sparked by the clade IIb strain of the monkeypox virus.