With the rise in breakthrough COVID cases amid the surge of the Delta variant nationwide, even vaccinated workers at UC San Diego health weren’t spared. The hospital system saw a significant increase in infections from June to July this year, even though more than 80% of its employees are fully vaccinated.
According to data from UCSD recently published in the New England Journal of Medicine, from March through July, a total of 227 workers tested positive. Of those, 57% were vaccinated.
Dr. Francesca Torriani is a UCSD Professor of Clinical Medicine. She is also the Program Director of Infection Prevention and Clinical Epidemiology and one of the researchers on this study.
Torriani said the total number of symptomatic COVID-19 cases went up from 15 cases in June to 125 in July, with 75% of the cases occurring in fully vaccinated employees. “This is a very healthy population and quite young. The median age was 39,” she said.
While the number of cases represented a small percentage of UCSD Health’s overall workforce of 19,000 people, 87% of whom are vaccinated, the growing number of infections points to a drop in the effectiveness of the vaccines. This, argues Dr. Torriani, means people will need a booster dose and to continue to wear masks.
“We believe that there is some evidence that the vaccine is waning. We believe it might suggest that boosters are needed very soon,” she said.
During this study period, which was March through July, one unvaccinated UCSD hospital worker was hospitalized and there were no reported deaths.
Dr. Torriani and other medical experts say breakthrough infections -- infections in vaccinated people -- tend to be mild, and vaccines are still highly effective against severe disease and death from the Delta variant.