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RCOG welcomes the launch of COVID vaccine in pregnancy study

News 3 August 2021

A new government-funded study looking at the COVID-19 vaccine dose interval for pregnant women has been announced today.

This will be the country’s largest clinical trial that will investigate the immune response to vaccination at different dose intervals, monitoring the protection provided by the vaccine for pregnant women and their babies.

With £7.5 million of government funding, the study will be led by St George’s, University of London, and will gather more robust data on how we can best protect pregnant women and their babies from COVID-19.

Dr Pat O’Brien, Vice President of the Royal College of Obstetricians and Gynaecologists, said “We now have robust data of nearly 200,000 women from across the US and the UK, who have received the COVID-19 vaccine with no safety concerns. This tells us that both the Moderna and Pfizer vaccines are safe in pregnancy. However, more research is needed to monitor and understand how pregnant women respond to the COVID-19 vaccine.

“We welcome this trial as the next step in further monitoring the protection provided by the vaccine, to understand the risk of any potential adverse side effects, and observe the immune response within those who are pregnant and their babies.

“We encourage all pregnant women to get vaccinated, as the protection that it provides against COVID-19 to both mother and baby outweigh the risks. We are seeing more pregnant women being admitted to hospital with COVID-19, and we know that the Delta variant is causing more pregnant women to have severe illness than previous strains of the virus.

“We hope that this research will help to gain the confidence of pregnant women that the recommendation of vaccination in pregnancy is based on robust evidence.”


Contact the RCOG press office on +44 (0) 7986 183167 or email

Notes to Editors

  • Volunteers can sign up to the trial here:
  • The trial was commissioned by the Department of Health and Social Care through the National Institute for Health Research (NIHR) and funded by the Vaccine Taskforce, with the study being undertaken by St George’s, as part of the National Immunisation Schedule Evaluation Consortium (NISEC).
  • Participants will be blinded to the vaccine they receive. The majority of participants will also be blinded to the interval between doses. This will be done by incorporating the routine whooping cough vaccine into the trial schedule. Participants will be followed up for one year after their baby is born.
  • NHS England research on pregnant women in hospital due to COVID-19 can be found here:
  • This trial has received ethics approval by the NHS Research Ethics Committee (part of the Health Research Authority), as well as approval from the Medicines and Healthcare products Regulatory Agency (MHRA). 

About RCOG

The RCOG is a medical charity that champions the provision of high-quality women’s healthcare in the UK and beyond. It is dedicated to encouraging the study and advancing the science and practice of obstetrics and gynaecology. It does this through postgraduate medical education and training and the publication of clinical guidelines and reports on aspects of the specialty and service provision.