A new study provides more evidence that a single dose of coronavirus vaccine might be enough to significantly reduce disease.
People who got a single dose of Pfizer/BioNTech coronavirus vaccine were increasingly less likely to develop Covid-19 symptoms as time passed -- and they were 85% less likely to get sick two to four weeks after getting their first shot, Israeli researchers report.
The findings, released as a letter to the Lancet medical journal, are likely to bolster calls for governments to move to a single-dose regimen to stretch out vaccine supply until manufacturers can make more.
How the study was conducted? The team at Israel’s Sheba Medical Center looked at the medical records of roughly 9,000 health care workers, more than 7,000 of whom were vaccinated starting in December.
“By Jan 24, 2021, of the 9,109 eligible staff, 7,214 (79%) had received a first dose and 6,037 (66%) had received the second dose,” they wrote.
More than 90% got their second dose on time, by 21 or 22 days after the first dose.
The team looked at the rate of infections during those crucial three weeks. They found a 47% reduction in symptomatic coronavirus infections among the health care workers during the first two weeks after the first shot and an 85% reduction over the following two weeks.
“Of the 170 healthcare workers who became infected, 89 (52%) were unvaccinated, 78 (46%) tested positive after the first dose, and three (2%) tested positive after the second dose,” they wrote.
It’s possible that asymptomatic cases were missed. The team only counted people who had symptoms and tested positive for coronavirus.