close up hand of doctor put label covid-19 vaccine sticker on vaccination certificate card and passport

A new study from Israel has found lower rates of SARS-CoV-2 infection among healthcare workers who received booster shots of the Pfizer vaccine.

Investigators followed outcomes in approximately 1,900 workers at a tertiary medical center in Tel Aviv. All were previously vaccinated with a two-dose series of the Pfizer vaccine. During 39 days of follow-up, receipt of a booster dose was significantly associated with lower risk of infection when compared with not receiving one, they reported.

The study took place in August and September 2021. Notably, about 70% of the breakthrough infections seen were symptomatic, “similar to the proportion observed in other studies of vaccine breakthrough infection,” the authors wrote.

The findings support those of an earlier nationwide study of adults aged 60 years and older, the researchers said. That study also found a lower rate of infections in boosted participants. The results also are in line with a reduction in hospitalizations found across multiple age groups in a large observational study, the researchers said.

Israel has been quick to release evidence-based data on vaccine efficacy and has been a trusted data source for other countries including the United States. 

Full findings were published in JAMA.