Looking at vaccinated health care workers at two University of California campuses, researchers found a tiny number tested positive for the virus. This finding highlights the need to keep wearing a mask and to keep social distancing, the researchers said.
“Because of the compulsory daily symptom screening of health care personnel, patients and visitors, and the high testing capacity at both UC San Diego Health and UCLA Health, we were able to identify symptomatic and asymptomatic infections among health care workers at our institutions,” said researcher Dr. Jocelyn Keehner. She is an infectious disease fellow at University of California, San Diego (UCSD) School of Medicine.
“Moreover, we were able to describe the infection rates in a real-world scenario, where vaccine roll-out coincided with a surge of infections. We observed a low overall positivity rate among fully immunized health care workers, supporting the high protection rates of these vaccines,” she said in a school news release.
For the study, Keehner’s team pooled data from health care workers who received either the Pfizer or Moderna vaccines between December 16, 2020, and February 9, 2021. There were more than 36,600 first doses, and more than 28,000 were fully vaccinated (two doses).
Among those vaccinated, 379 tested positive on at least one day following vaccination, with the most (71%) testing positive within the first two weeks after the first dose of vaccine. However, 37 workers tested positive after receiving two doses, when they are supposed to have maximum protection.
The researchers estimated that the absolute risk of testing positive for COVID-19 after vaccination was about 1% for health care workers, which was higher than the risk seen in clinical trials, which were not limited to health care workers.
Source: UCSD & US World Report
