This site is optimised for modern browsers. For the best experience, please use Google Chrome, Mozilla Firefox, or Microsoft Edge.

Com-COV vaccine study recruiting in London to analyse third dose booster options for 12- to 15-year-olds


Researchers running the University of Oxford-led Com-COV programme have launched a new study of COVID-19 vaccine schedules in young people aged 12 to 15 years – with a focus on assessing different options for a third dose booster vaccination. Volunteers are being invited to take part in the study at Royal Free London NHS Foundation Trust and St George’s University Hospitals NHS Foundation Trust.

The Com-COV 3 study has been commissioned through the National Institute for Health and Care Research (NIHR) and aims to recruit 380 volunteers across nine NIHR-supported sites. All participants will have received two doses of the Pfizer-BioNTech vaccine, at least three months before joining. Researchers will deliver a third vaccine dose as part of the study.

Matthew Snape, Professor in Paediatrics and Vaccinology at the University of Oxford, and Chief Investigator of the trial, said:

“This study builds on the important results from previous studies, which have directly informed the national and international use of mixed COVID-19 vaccine schedules. These studies have included teenagers receiving the first two vaccine doses.

“A key question for teenagers now is how well they respond to different options for a third dose of vaccine – and we now need the help of young people in London to help us answer this. If these can be shown to produce a strong immune response with fewer temporary side effects, then this could improve the acceptability and uptake of a third dose adolescent campaign, both in the UK and internationally.”

All participants will be randomly allocated to receive either a full adult dose, one-third adult dose or full child dose of the Pfizer-BioNTech vaccine, or a full dose of the Novavax vaccine. A control group will receive a meningitis vaccine (Bexsero, against MenB bacteria) followed by a Pfizer-BioNTech COVID-19 vaccine later in the study.

The study is single-blind and randomised. This means participants will not know what third dose vaccine they are receiving until three months later. Researchers will analyse the reactogenicity (any side effects) and immune system responses to these new combinations of vaccines. They will also examine if a one-third adult dose of the Pfizer-BioNTech vaccine is at least as good as a full child dose of the same vaccine.

Professor Andrew Ustianowski, NIHR Clinical Lead for COVID-19 Vaccination Programme and Joint National Infection Specialty Lead, said:

“It's very important that continued research into how we can best protect teenagers against COVID-19 takes place. The Com-COV 3 study will help us to develop a better understanding of adolescents immunity when it comes to booster jabs.

“Thousands of volunteers are still stepping forward for a number of vaccine booster studies, 2 years on since we began to recruit into the first COVID-19 vaccine studies. Their time, support and generosity has been immense and helps us build upon the science of vaccine combinations. The latest stage of the Com-COV 3 study will be key to providing important data on protecting young people and their families.”

Paul Heath, Professor of Paediatric Infectious Diseases at St George's, University of London and Principal Investigator for the Com-COV 3 study at St George’s University Hospitals NHS Foundation Trust, said: "We must continue research into how best to protect teenagers against COVID-19. The Com-COV 3 study will provide important information on young people's immunity regarding booster jabs."

Dr Kin Man, Principal Investigator for the study at the Royal Free, said: “It is vital that we understand more about how to give teenagers the best protection against COVID-19, and this study will help us do that.”

The study investigators anticipate reporting initial results in 2022. The UK’s regulatory body, the Medicines and Healthcare products Regulatory Agency (MHRA) rigorously assess the safety and efficacy of any new vaccine before considering market authorisation and subsequent rollout to patients. The Joint Committee on Vaccination and Immunisation (JCVI) provide expert guidance to UK health departments on vaccination, which takes into account a range of evidence, including data from trials undertaken to understand the immunological impact of booster vaccinations.

All those who are interested can register via the study website: