Study Detail

Comparing COVID-19 Vaccine Schedule Combinations - Stage 2 (Com-COV2)

A single-blind, randomised, phase II UK multi-centre study to determine reactogenicity and immunogenicity of heterologous prime/boost COVID-19 vaccine schedules - Stage 2

Status: Closed

Type: Interventional


Sponsor: University of Oxford

CI: Dr Matthew Snape

IRAS-Number: 297443

CPMS-ID: 48968

Approval Date: 25 March 2021


On the 2nd December 2020 the MHRA granted emergency authorisation for a vaccine against COVID-19, 'COVID-19 mRNA Vaccine BNT162b2'; the European Medicines Agency then granted conditional authorisation on 21st December 2020. This was followed by emergency authorisation of the Oxford/AstraZeneca ChAdOx1 nCOV-19 vaccine on the 29th December 2020 by the UK MHRA. The MHRA then similarly granted emergency authorisation for the mRNA COVID-19 Vaccine Moderna on 8th January 2021. The adjuvanted protein COVID-19 vaccine from Novavax, NVX-CoV2373, is under rolling review of the MHRA at the time of writing. All of these vaccines were originally developed for use as homologous two-dose regimens. There are likely to be significant logistical challenges immunising large portions of the population. There would be significant advantages to having flexible immunisation programmes whereby the second vaccine dose is not necessarily the same as the first dose. Accordingly, this study will determine the safety as well as the immune responses to a variety of combinations of prime/boost schedules for COVID-19 vaccines that are deployed, or will potentially be deployed, in the UK. The vaccines to be studied in this protocol will primarily be determined by those made available to the Department of Health and Social Care (DHSC) for population use. This study follows on and works in parallel with the Com-COV study to answer the same questions in a pandemic-relevant timeframe but involving different vaccines, and with randomisation at dose two rather than dose one.

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