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Pfizer and Moderna vaccines ‘safe and effective’ in pregnant women


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The Pfizer/BioNTech and Moderna Covid vaccines are ‘safe’ for pregnant and lactating women, and offer strong immunity against the virus, a study published in the American Journal of Obstetrics and Gynecology has found. 

The US study analysed the effects of the two vaccines on 84 pregnant, 31 lactating, and 16 non-pregnant women, with samples collected between 17 December and 2 March.

The researchers found that the Covid-19 mRNA vaccines generated ‘robust’ protection in pregnant and lactating women, with the immunity levels and side effects ‘similar to that observed in non-pregnant women’, adding that immunity also transferred via placenta and breastmilk.  

Although the report said the research data does not ‘elucidate potential risks [of the vaccine] to the fetus’, senior co-author of the study Professor Galit Alter told Pulse out of 10 babies that were born to date, none were adversely affected.

She also added: ‘We did see transfer of antibodies in the cord and the breast milk, suggesting that vaccines also deliver antibodies to the babies to empower them to fight the infection, should they come into contact with the virus after birth.’

The study highlights the vaccines are ‘safe’ for the pregnant mothers themselves, she added.

The US study said the immune response from the vaccine proved to be ‘significantly greater’ than that achieved through natural infection.

Pregnant and lactating women were excluded from the initial Covid-19 vaccine trials, meaning ‘data to guide vaccine decision-making are lacking’, the study said. 

In a statement, Professor Alter said: ‘We now have clear evidence the Covid vaccines can induce immunity that will protect infants’. 

‘We hope this study will catalyze vaccine developers to recognize the importance of studying pregnant and lactating individuals, and include them in trials. We look forward to studying all vaccine platforms in pregnancy as they become available.’ 

The MHRA authorised the Moderna vaccine for use in the UK in January, with doses set to become available from the spring, while Pfizer has been in use since December.

In January, the JCVI updated its guidance to state that women who are pregnant should be offered a Covid vaccination, adding this should be considered where the risk of exposure to [Covid] is high or where the patient has underlying conditions that places them at very high risk. 

Vaccination has been deemed safe when breastfeeding, and the JCVI has stressed the reason for caution in pregnant women is only due to a lack of data rather than any evidence of adverse effects.