Publish date: 21 May 2021

The study aims to improve understanding of the safety, tolerability and immune response generated by the Pfizer-BioNTech Covid-19 vaccine in healthy pregnant women, with approximately 235 volunteers involved throughout the UK.

Following updated guidance from the Joint Committee on Vaccination and Immunisation (JCVI) released in April, pregnant women are now offered approved Covid-19 vaccines at the same time as the rest of the UK population, based on their age and clinical risk group. Real-world data from the United States has been collected, in which over 100,000 pregnant women have been vaccinated (mainly with mRNA vaccines including Pfizer-BioNTech), without any safety concerns raised.

The role of this placebo-controlled study (Covid-19 Vacc Maternal Immunisation) is to provide more robust information on the vaccine immune response in pregnancy, as well as safety reporting and the potential transfer of maternal antibodies to infants.

Each participant enrolled in the study will initially receive either two doses of the vaccine or a placebo 21 days apart. All participants will be unblinded one month post pregnancy, and those who were given the placebo jab (a saltwater solution that does not contain any active ingredients) will receive the Pfizer-BioNTech COVID-19 vaccine.

Dr Eleni Nastouli, Principal Investigator of the trial at UCLH, said: “This study will give us important information enabling us to better understand the immune response induced by the Pfizer-BioNTech vaccine in pregnant women, as well as its safety – importantly in a clinical trial setting with long follow up. It will also provide very helpful information on the transfer of antibodies from mother to baby.”

Recruitment will begin this week at the UK sites involved. The study has already been running in the US since February 2021. Research participants will answer questionnaires about their health, provide blood samples, complete an e-diary and will receive extra monitoring while on the study, compared to those who receive a vaccine through the rollout.

All volunteers will need to visit their site for four planned visits before their baby is born and then two more follow up appointments after the baby is born.

Image: Marina Demidiuk / Adobe Stock