Pfizer and BioNTech have started an international study with 4,000 volunteers to evaluate the safety and effectiveness of their COVID vaccine in healthy pregnant women, Report informs, referring to CNBC.
Pregnant women are at higher risk of developing severe COVID, and many public health officials have recommended some women in high-risk professions take coronavirus vaccines even without proof they are safe for them.
Pregnant women in the US have already received their first doses, the companies said.
The new study will test pregnant women aged 18 and older in the United States, Canada, Argentina, Brazil, Chile, Mozambique, South Africa, the UK, and Spain.
Women will receive the vaccine during weeks 24-34 of gestation, getting two shots 21 days apart - the same regimen used in the larger clinical trial.
Shortly after giving birth, participants who got a placebo in the trial will be given an opportunity to get the actual vaccine while remaining part of the study, the companies said.