Covid Protection Wanes Months After Second Shot, Booster Needed: Study

Covid Protection Wanes Months After Second Shot, Booster Needed: Study The antibody levels fell first at a sharp pace and later at a more moderate one.

Immunity provided by the Covid-19 vaccine from partners Pfizer Inc. and BioNTech SE weakens significantly within months, with men having less protection than women, according to research that supports the use of booster doses.
Protective antibodies decreased continuously during the six months after the administration of the second dose of the vaccine, according to a study of about 5,000 Israeli health workers, published Wednesday in the New England Journal of Medicine. The levels fell first at a sharp pace and later at a more moderate one.

Researchers worldwide are trying to identify the critical threshold of antibodies needed to prevent coronavirus infection, severe illness and death, said Gili Regev-Yochay, one of the authors of the study. Such studies will help assess risk levels for various groups and the measures needed to protect them, the researcher said.

Antibody levels were found to be lower in older people than in younger, and in immunosuppressed individuals compared to the healthy population, according to the study from Sheba Medical Center in Ramat Gan. Men’s antibody counts were lower than those of women both at their peak and at the end of the study.

The research shows why there are breakthrough infections in individuals who have had two vaccine doses, Regev-Yochay said in an online press briefing. The U.S., which has restricted its booster recommendation to older people and other vulnerable groups, will likely follow Israel’s decision to offer a third dose to the entire population, she said.