Yonatan Oster, M.D., from the Hebrew University of Jerusalem in Israel, and colleagues compared all vaccinated HCWs who had positive test results for SARS-CoV-2 at least two weeks after receiving the second BNT162b2 vaccine dose to nonvaccinated workers who had positive test results and a sample of vaccinated workers who were tested for SARS-CoV-2 but had negative results (vaccinated-positive versus nonvaccinated-positive and vaccinated-negative [27, 63, and 81 HCWs, respectively]).

The researchers found that exposure to a positive household member was significantly more common among HCWs in the vaccinated-positive group versus the nonvaccinated-positive group and vaccinated-negative group (56 percent versus 38 and 9 percent, respectively). Among vaccinated-positive HCWs, the odds ratio for exposure to positive household members was 2.03 (95 percent confidence interval, 0.74 to 5.62) compared with nonvaccinated-positive HCWs and 12.5 (95 percent confidence interval, 3.70 to 43.23) compared with vaccinated-negative HCWs.

"The findings of this case-control study suggest reconsideration of quarantining vaccinated people who have had significant exposure to household members who are positive for SARS-CoV-2 infection," the authors write.

One author disclosed financial ties to the biopharmaceutical industry.

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