The US National Institutes of Health (NIH) has announced the launch of a study to evaluate the immune responses generated by COVID-19 vaccines in pregnant or postpartum women.

Pregnant women are at higher risk of complications from COVID-19 including premature birth, high blood pressure with organ failure risk, need for intensive care and possible death, according to the NIH.

A small study conducted in February in Israel showed that antibodies were detected in all 20 women administered with both doses of the Pfizer-BioNTech vaccine during their third trimester of pregnancy and also in their newborns.

Pfizer and BioNTech started a separate trial in February with 4000 international volunteers, evaluating safety and effectiveness of their COVID-19 vaccine in healthy pregnant women.