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Com-COV alternating vaccine dose study expands to 12-to-16-year-olds

Published: 17 September 2021

A COVID-19 vaccine study backed through funding from the Vaccines Taskforce and NIHR has expanded to include people aged 12 to 16, as it looks to analyse different vaccination schedules in young people. 

The Com-COV 3 study, led by the University of Oxford and the National Immunisation Schedule Evaluation Consortium, will recruit 360 volunteers across four NIHR-supported sites.

Participants can either receive two COVID-19 vaccine doses in the study, in which case their first dose will be the Pfizer COVID-19 vaccine. Alternatively, those who have already received a dose of the Pfizer COVID-19 vaccine through the NHS can be enrolled at the time of their second dose.

All participants will be randomly allocated at the time of the second dose to receive either a full dose or half dose of the Pfizer-BioNTech vaccine, a full dose of the Novavax vaccine or a half dose of the Moderna vaccine. 

Professor Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, and Chief Investigator on the trial, said:
“This study will provide vital information on the range of options for immunising teenagers against COVID-19 in the UK. 

“As well as looking at the standard two full doses of the Pfizer vaccine, we will look at how well volunteers respond when their second dose of Pfizer is half that of the first dose, or if different vaccines are used altogether, such as the vaccines manufactured by Moderna or Novavax. This will provide the JCVI with information crucial to informing their advice about immunising teenagers in the UK.”

“This is the latest in a series of studies such as Com-Cov and COV-Boost that have looked at ways the different COVID-19 vaccines available in the UK can be used to generate the best and most durable immune response, in as safe a manner as possible.”

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

“It is important to establish the most effective vaccine doses for different population groups, and this latest study will help develop our understanding of immune responses for young people once vaccinated against COVID-19.

"We continue to see valuable contributions from volunteers across COVID-19 vaccine research across the UK to help us identify the best vaccine schedules, and I hope we see similar levels of engagement with the Com-Cov 3 study.”

Researchers will assess reactogenicity (any side effects) and immune system responses to these new combinations of vaccines. The study is single-blind and randomised, meaning participants will not know what second dose vaccine they are receiving. 

The study will take place at four sites, including St George's University Hospitals NHS Foundation Trust, University Hospitals Bristol and Weston NHS Foundation Trust, University Hospital Southampton NHS Foundation Trust and the Oxford Vaccine Group, University of Oxford.

If the results are promising, regulators MHRA and JCVI would formally assess the safety and efficacy of any new vaccination process before advising whether it is rolled out to patients. - with the study aiming to report initial results by December.

All those who are interested can register via the Com-Cov study website.

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