LONDON (Reuters) – A British investigation into the use of various COVID-19 vaccines in two-dose vaccinations is being extended to shots made by Moderna and Novavax, researchers said on Wednesday.
The trial, known as the Com-Cov study, was first launched in February to see if giving a first dose of one type of COVID-19 shot, and a second dose of another , elicits an immune response that is just as good as taking two doses of the same vaccine.
The idea, said Matthew Snape, a professor at Oxford University who led the trial, “is to investigate whether the multiple COVID-19 vaccines available can be used more flexibly”.
Britain and many other European countries are currently using the COVID-19 vaccines of AstraZeneca and Pfizer in nationwide vaccination campaigns against the coronavirus pandemic.
But reports of very rare blood clots have prompted some governments, including France and Germany, to say that the AstraZeneca shot should only be given to certain age groups, or that people who had a first dose of AstraZeneca vaccine should go to another one should switch for their second dose.
In an information session on the extension of the study with the COVID-19 vaccines Moderna and Novavax, Snape, an associate professor of pediatrics and vaccination at Oxford, said he was trying to recruit adults over 50 who had their first, or ‘first’ Vaccination in the last 8-12 weeks.
These volunteers, who have received the AstraZeneca or Pfizer vaccine, will be randomly assigned to receive the same vaccine, or the Moderna or Novavax vaccine, for a second dose.
The six new arms of the trial will involve 175 people each, adding another 1,050 recruits in total, Snape said.
“If we can show that these mixed schedules elicit an immune response that is as good as the standard schedules, and without a significant increase in vaccine responses, it will be possible for more people to complete their COVID-19 immunization course more quickly,” he said. Snape said.
“It will also create resilience in the system in the event of a shortage of availability of any vaccines.”
Results of the original mixing test, with AstraZeneca and Pfizer shots only, are already expected in April or May, while the result of the second phase would be in July.
Reporting by Kate Kelland. Edited by Mark Potter