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Fourth Pfizer Dose Slashed Risk of Catching Omicron in Study

  • Infections were reduced by two thirds after second booster
  • Extra shot can help avoid medical staff shortages, authors say

Hospital workers who got a fourth dose of Pfizer Inc.’s messenger RNA vaccine were far less likely to get Covid than triple-vaccinated peers in a study. 

The findings published Tuesday in the American Medical Association’s open access journal are the latest to confirm the benefits of a second booster against breakthrough infections caused by omicron. The study’s authors pointed to an extra dose as a tool to prevent medical staff shortages and spare health systems in times of strain.