Covid-19 vaccines may have prevented thousands of premature births, study suggests

Covid-19 vaccinations may have prevented thousands of premature births, new research suggests.

Mothers infected with the Covid virus were significantly more at risk of delivering early in the beginning stages of the pandemic, prior to the rollout of vaccines, according to the study, published in the Proceedings of the National Academy of Sciences.

The research analysed millions of California birth records from 2014-2023, which are reflective of global pregnancy trends prior to, during and after the Covid pandemic,scientists said.

Covid-19 can endanger pregnancies by causing inflammatory responses, which in turn risks the deterioration of the placenta and an early birth.

From July to November 2020, the risk of a mother delivering at least three weeks before her due date increased by 78 per cent for those infected with Covid-19, and increased by 58 per cent by the autumn of 2021. 

‘This is still an evolving epidemic’

However, the risk of a premature birth in mothers infected with Covid-19 returned to pre-pandemic levels by 2022 – attributed in large part to the vaccine rollout. 

This reduction was recorded almost a year earlier in areas of California with higher vaccine uptake.

“In ZIP codes with the highest vaccination rates, the excess risk of preterm birth declines much faster,” said Jenna Nobles, a professor at the University of Wisconsin-Madison and co-author of the study. 

“By the summer of 2021, having Covid-19 in pregnancy had no effect on preterm birth risk in these communities. It takes almost a year longer for that to happen in the ZIP codes with the lowest vaccine uptake.

“That highlights how protective Covid vaccines have been. By increasing immunity faster, early vaccination uptake likely prevented thousands of preterm births in the US.”

However, researchers warned the risk posed by Covid-19 to pregnant women has not completely disappeared. 

“This is still an evolving epidemic, and the rate of vaccine boosters among pregnant people right now is very low,” Ms Nobles said.

“The question is: how many more iterations of viral evolution does this need to escape the immunity that we have? It’s miraculous and incredible that we’re now down to essentially zero additional preterm births, but it does not indicate that it’s going to be that way in perpetuity.”

Premature birth can cause a host of short and long-term health conditions, including cerebral palsy, learning difficulties, visual and hearing problems, and behavioural issues. Globally, complications from being born prematurely are the leading cause of death among children under five. 

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