On Tuesday, Pfizer Inc and BioNTech SE applied for emergency use authorization with U.S. regulators for a second booster dose of their COVID-19 vaccine for people aged 65 years and above.The companies said that a much lower rate of confirmed infections and severe disease was seen in an analysis of data from over a million adults, aged 60 years and older, who received an additional booster dose of the vaccine at least four months after the third dose compared to those who were given just one booster shot. The data also suggested that a fourth dose led to a considerable improvement in protection against the Omicron variant compared to the third dose after three-to-six months.

The submission to the U.S. Food and Drug Administration included data from Israel, where a second booster shot is authorized for many people over age 18 years. In late January, based on health ministry data, Israel said that a fourth dose enhanced the protection against infection 2 times, and 3-5 times against severe disease, compared to people who had received three shots.Pfizer was now designing its study on around 600 people to evaluate the efficacy of the fourth dose. (Reuters, March 16, 2022)