Image of Covid-19 vaccination record card with vials and syringe.

A second booster shot lowers the risk of dying from COVID-19 illness by 78% in seniors. That’s according to a new study from Israel, which approved a second dose in January.

Investigators examined outcomes over 40 days for half a million adults aged 60 to 100 years old from the country’s Clalit Health Services system database. More than half of these patients (58%) had received a second booster dose of the Pfizer-BioNTech vaccine at least four months beforehand. The other half had received one booster dose only. The 40-day study period covered a time when Israel’s omicron infections were among the highest in the world, the researchers reported.

There were 232 deaths among patients who did not receive a second booster and 92 deaths among those who did, according to the results, which have yet to be peer-reviewed. The 78% lower rate of death among the twice-vaccinated group was notably lower than the rate of death found among the elderly population of Israel after a first dose (90%), the researchers noted.

The approval of a first booster dose in Israel significantly reduced infections and hospitalizations, the investigators wrote. But post-booster immunity waned within a few months, a finding echoed by federal research in the United States as well. An uptick in infections related to the omicron variant prompted Israeli health officials to approve a second dose for adults aged 60 and older, they said.

White House to greenlight 2nd shot this week

In the United States, meanwhile, the Biden administration has signaled that it will authorize second booster shots for anyone 50 years old or older as early as this week, according to various news outlets. The move is in response to concerns about an expected increase in COVID-19 cases due to the omicron BA.2 variant currently plaguing Asia and Europe, sources said.

The researchers hope the findings provide evidence for future policy decisions and will encourage more people to receive a second booster dose.

“The objective of the second booster, and the policy now, is to reduce hospitalizations and infections,” Ronen Arbel, Ph.D., of Clalit, told the Jerusalem Post. “Our objective is to reduce severe diseases and mortalities in people above the age of 60.”

Full findings were published on the public preprint repository Research Square.