LONDON (Reuters) – A UK study on the use of different COVID-19 vaccines in two-dose inoculations is being expanded to include shots fired by Moderna and Novavax, researchers said on Wednesday.
The trial, known as the Com-Cov study, was first launched in February to examine whether giving a first dose of one type of COVID-19 and a second dose of another elicits an immune response as good as use two doses of the same vaccine.
The idea, said Matthew Snape, a Oxford University professor leading the trial, “is to explore whether the multiple COVID-19 vaccines available can be used more flexibly.”
Britain and many other European countries currently use AstraZeneca and Pfizer COVID-19 vaccines in national 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 have had a first dose of AstraZeneca vaccine should be changed to a second dose.
In a briefing on expanding the study to include COVID-19 vaccines from Moderna and Novavax, Snape, an associate professor of pediatrics and vaccinology at Oxford, said he would seek to recruit adults over the age of 50 who have received the first ”Vaccination in the last 8-12 weeks.
These volunteers, who will have received the AstraZeneca or Pfizer vaccine, will be randomly assigned to obtain the same vaccine or the Moderna or Novavax vaccine, for a second dose.
The six new arms of the trial will each involve 175 people, totaling 1,050 recruits, Snape said.
“If we can show that these mixed programs generate an immune response as good as standard programs and without a significant increase in vaccine reactions, this will possibly allow more people to complete the COVID-19 vaccination course more quickly,” he said. Snape.
“This would also create resilience within the system in the event of a lack of availability of any of the vaccines.”
The results of the original mixing trial, which only uses features from AstraZeneca and Pfizer, are expected in April or May, while the results of the second phase should arrive in July.
Report by Kate Kelland. Edited by Mark Potter