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Pregnant women called upon for COVID-19 vaccine study to shape future guidance

Preg Cov COVID 19 Vaccine Study Banner

A national COVID-19 vaccine study is urging pregnant women across England to step forward and help researchers discover the most effective use of vaccines during pregnancy to protect women and their babies against COVID-19. To identify the best interval between vaccine doses, during and following pregnancy, more volunteers are urgently needed to join the Preg-CoV study.

Led by researchers at St George’s, University of London, the study compares vaccines currently being used for the UK vaccination programme (Pfizer/BioNTech and Moderna) as well as new vaccines as they are approved. The NIHR-supported study will provide vital clinical trial data on the immune response to vaccination at different dose intervals - either four to six weeks or eight to 10 weeks.

The current UK guidance is that COVID-19 vaccination should be offered to pregnant women at the same time as the rest of the population. COVID-19 vaccines are safe and effective for pregnant women, and there is a clinical consensus that it is the best way to protect you and your baby from COVID.

Recent data shows 1 in 5 of the most critically ill COVID-19 patients are pregnant women who have not been vaccinated.


Data from UK Health Security Agency showed that over 84,600 pregnant women have received the first dose of the life-saving COVID-19 jab, and around 80,700 have received their second dose. However, further pregnancy-specific research is currently happening in the UK to provide more data around the most effective vaccines, and the best gap between vaccine doses for pregnant women.

Hundreds of women are needed in order to help provide further findings key to protecting more women and shaping future vaccine guidelines. The study launched in August 2021, and will involve 600 pregnant women, across 14 NIHR-supported sites across England. Volunteers will be closely monitored by health professionals throughout their pregnancy and following the birth.

Chief Investigator and Professor of Paediatric Infectious Diseases at St George's, University of London, Professor Paul Heath said: 

“Over two hundred and fifty thousand pregnant women have now been vaccinated with COVID-19 vaccines in both the US and the UK, with no major safety concerns reported. But we do not yet know the best schedule to use to provide the maximal protection for pregnant women against COVID-19 and this is what we are addressing in this study. 

“We need even more pregnant women across the country to join the study. Not only will they receive special monitoring and support around their vaccines, but they will help shape future guidelines and protect pregnant women in the future. It is a really worthwhile, helpful thing to do.”

Pregnant women in the study will receive monitoring and additional support through study visits, compared to those who receive their vaccine outside of the study. They will also be provided a 24 hour phone line should they have any questions for the trial team and an electronic diary to record any symptoms. They will also be reimbursed for travel to their study appointments.

Debbie, 36, lives in Cornwall and volunteered to take part in the study at the Royal Cornwall Hospital.

“Becoming pregnant during the pandemic, my main concern was will my baby be okay. So in fact, it was only after joining the study that I slowly began to relax and begin to enjoy my pregnancy with less stress and fear around COVID," she explained.

“I couldn’t wait for the study to start and felt more confident and comfortable about having the vaccine this way than heading to a local drop in centre. It gave me the confidence that I was going to be looked after during my vaccination journey. It provided everything I needed, which was health professionals such as a midwife, doctors and nurses who had the knowledge and experience around the vaccinations and the effects of COVID during pregnancy.

“I had so many questions and concerns as I joined the study which were all addressed by the study team. I even got to hear my baby's heartbeat and the thorough assessment I underwent before receiving my first vaccination gave me the comfort and confidence that myself and my baby were in safe hands.

“I feel more pregnant women who are on the fence or concerned about what is best to do about getting vaccinated should definitely join the study. It changed my whole pregnancy experience being pregnant during a pandemic to a more positive experience and I have felt much safer as a pregnant woman since joining.”

Once successfully enrolled, most participants will be randomised to receive two doses of an approved COVID-19 vaccine with either a short-time interval (4-6 weeks) or a long-time interval (8-10 weeks) between doses, with the majority of volunteers blinded to which vaccine they receive. For some participants this means they will receive their second dose after delivery. Participants will receive a single dose if they have already received their first dose or if they just need a booster (3rd) dose). All participants and their babies will be followed up until one year after delivery.

The study is seeking low-risk, carrying a single baby, pregnant women aged 18-45 years-old and between 13-34 weeks gestation. It is also recruiting participants who have already had two doses of a COVID-19 vaccine in the community.

Ruth Bowen, a Research Midwife working on the study at the Royal Cornwall Hospital, explained: “There’s a misunderstanding of receiving COVID-19 vaccines during pregnancy, which has probably put some pregnant women off getting vaccinated. It has been really hard seeing pregnant women receiving care in hospital due to COVID-19, especially because it could have been prevented by getting the COVID-19 vaccine. By joining the Preg-CoV study, pregnant women not only receive extra monitoring and support while getting their vaccines,
but also help us to gather important data to better protect expecting mothers more effectively in the future.

“The findings from vaccine studies will help supply information and provide more confidence to pregnant women now and moving forward.”

Georgina, another participant in the study explained: It is both interesting and rewarding to take part in this study. I wanted to get involved because I wanted to give something back.

“When the trial came about it seemed like the perfect opportunity to help medical research, while also getting vaccinated and extra care in my pregnancy.”

The study will collect blood samples from participants, with a cord blood sample taken after delivery for some participants. For all participants, a baby blood sample will be taken between 4 and 12 weeks of age. Breastmilk samples will also be collected for a sub-group of participants.

If you are interested in the study, or know someone who could be eligible, you can find out more by visiting the study’s website.