On Apr. 14, 2021, researchers running the Com-Cov study, launched in February to investigate alternating doses of the Oxford-AstraZeneca vaccine and the Pfizer vaccine, have announced that the programme was extended to include the Moderna and Novavax vaccines in a new study.

Led by the University of Oxford, run across nine National Institute for Health Research supported sites by the National Immunisation Schedule Evaluation Consortium, and backed through funding from the Vaccines Taskforce and the Coalition for Epidemic Preparedness Innovations, the additional study will seek to recruit adults aged over 50 who have received their first, or ‘prime’ vaccination in the past 8-12 weeks.

Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, and Chief Investigator on the trial said: ‘The focus of both this and the original COM-COV study is to explore whether the multiple COVID-19 vaccines that are available can be used more flexibly, with different vaccines being used for the first and second dose.

‘If we can show that these mixed schedules generate an immune response that is as good as the standard schedules, and without a significant increase in the vaccine reactions, this will potentially allow more people to complete their COVID-19 immunisation course more rapidly.

These volunteers, who will have received either the Oxford-AstraZeneca, or Pfizer vaccine, will be randomly allocated to receive either the same vaccine for their second dose, or a dose of the COVID-19 vaccines produced by Moderna or Novavax. The six new ‘arms’ of the trial will each recruit 175 candidates, adding a further 1050 recruits into this programme.