Covid vaccine developers are set to begin trials in pregnant women, seeking to provide reassurance that shots for expectant mothers are safe.
According to the US online clinical trial registry, Pfizer Inc. and German partner, BioNTech SE is beginning trials for their messenger RNA vaccine in 4,000 women in the latter stages of pregnancy.
In order to confirm safety before moving into advanced trials for women between 24 and 34 weeks pregnant, the companies will conduct a mid-stage study for 350 volunteers between 27 and 34 weeks of gestation.
AstraZeneca Plc. and Johnson & Johnson are planning to run trials in the coming months. It’s good news for pregnant people, who until now have faced a difficult dilemma: excluded from vaccine studies, yet more vulnerable to severe Covid-19. Some studies have also linked the disease to premature birth.
“While it’s good news that vaccine trials in pregnant women are finally beginning, the results from these trials are unlikely to be available before the autumn,” said Marian Knight, professor of maternal and child population health at the University of Oxford.
Due to a lack of safety information and a potentially higher risk of adverse events, pregnant women were kept out of vaccine studies, despite calls from many scientists and physicians for their inclusion. As a result, unless they are at high risks, such as front-line health care workers, the US, UK and the World Health Organization have advised against vaccinating pregnant women.
The Pfizer-BioNTech study will be run in the US, Europe, South America and Africa and focuses on the third trimester of pregnancy to minimize risk to unborn children, BioNTech said in an e-mailed statement. The companies aren’t planning to evaluate whether the vaccine could have a preventative effect on babies after birth.
Trials begin in a bid to fill the global data void
Many companies have also set up registers to track respondents who were conceived after taking part in vaccine trials. In January, Astra and partner Oxford told a US panel that 21 women in the studies became pregnant after vaccination, while 23 women in the Pfizer-BioNTech studies reported that they were expecting it last year.
Andrew Pollard, the lead investigator on the Oxford-Astra UK trials, said that once all babies conceived in its study population have been followed up, the university will report results.
Current UK guidance recommends that if a low-risk woman becomes pregnant after the first shot, the second vaccine dose should be delayed.
Children’s vaccine trials have also only begun in recent months, with the first data expected by summer. While children generally do not suffer from severe Covid, they may be key to preventing transmission to vulnerable individuals, including at-home pregnant women.
“It is a gap and it’s one that we’re looking to see how we can address,” June Raine, chief executive officer of the UK Medicines & Healthcare Products Regulatory Agency, said at a board meeting Tuesday. “We do appreciate there’s a need for some more robust data.”
The US National Institutes of Health said Wednesday it’s beginning a study on the effects of Covid-19 treatment remdesivir in pregnant women. The antiviral drug from Gilead Sciences Inc. has been shown to accelerate recovery from severe disease and was approved by the US for use in Covid-19 patients last year.