Washington, Jun 24 (IANS): US researchers have started a new observational study to evaluate the immune responses generated by Covid-19 vaccines administered to pregnant or postpartum women, the National Institutes of Health (NIH) announced.

In its announcement on Wednesday, the NIH said that researchers will measure the development and durability of antibodies against SARS-CoV-2 in women vaccinated during pregnancy or the first two postpartum months, reports Xinhua news agency.

They also will assess vaccine safety and evaluate the transfer of vaccine-induced antibodies to infants across the placenta and through breast milk, according to the NIH.

The study will enrol up to 750 pregnant women and 250 postpartum individuals within two months of delivery who have received or will receive a Covid-19 vaccine authorised by the US Food and Drug Administration.

Their infants also will be enrolled in the study.

Participants and their infants will be followed through the first year after delivery.

To assess the development and durability of vaccine-induced antibodies overall and by vaccine type and vaccine platform, researchers will analyse blood samples collected from pregnant and postpartum participants, according to the NIH.

"Tens of thousands of pregnant and breastfeeding people in the US have chosen to receive the Covid-19 vaccines available under emergency use authorisation. However, we lack robust, prospective clinical data on vaccination in these populations," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

"The results of this study will fill gaps in our knowledge and help inform policy recommendations and personal decision-making on Covid-19 vaccination during pregnancy and in the postpartum period," he said.