Pfizer’s fourth shot reduces risk of contracting COVID: study

COVID-19 Vaccine – Canva/File
  • After the second COVID booster, infections dropped by two-thirds.
  • The authors say the extra shot could help prevent medical staff shortages.
  • The study was conducted in Israel.

Healthcare workers who received a fourth shot of Pfizer Inc.’s messenger RNA vaccine were significantly less likely to contract COVID than their triple-vaccinated peers, according to a study.

According to BloombergThe findings, published Tuesday in the Open Access Journal of the American Medical Association, are the latest to indicate the benefits of another booster against Omicron breakthrough infections. The study’s authors suggested that the supplement could be used to alleviate medical staff shortages and protect health care systems in times of crisis.

The study was conducted in Israel, where a rapid vaccine rollout provided researchers with real-world data on vaccine efficacy. In January, the country began providing a second booster to the elderly, health workers, and people with weakened immune systems.

With the emergence of the BA.5 Omicron variant, the US is now evaluating whether to add eligibility for other booster shots.

Doctors, nurses, and other health care workers who received the fourth mRNA shot in January had a 7 percent chance of developing a new infection. Those who received three doses, the third of which was delivered by the end of September, had a 20 percent infection rate.

According to experts, many Israeli health officials skipped the fourth dose in January, thinking it wouldn’t make much of a difference.

“The general consensus was that the combination of the reduction in virulence of the Omicron variant and the protection afforded by the first three vaccine doses did not create any additional value for the fourth vaccine,” they wrote. But for medical staff, he argued such a difference because “quarantine and isolation of large numbers of health care workers can affect the ability of the health system to function.”