Stady. The combination of vaccines increases the mild side effects

“It’s an interesting discovery, and we didn’t expect it,” said Matthew Snape, head of the investigation. BBC.

The Com-Vac study, launched in February, confirmed whether a dose different from the second could give greater and longer-lasting immunity, more protection against the new variants or simply allow vaccination centers to exchange vaccines in the event of a supply failure. The Canadian provinces of Ontario and Quebec have revealed that they plan to mix vaccines soon.

The study, led by the University of Oxford, involved 830 volunteers over the age of 50. Full results are expected in June. But introductory statements have already been published in the science journal The Lancet.

One in ten volunteers who received two doses of the AstraZeneca vaccine four weeks apart said they had a fever. In those who received a dose of AstraZeneca and a dose of Pfizer, regardless of the order of administration, the proportion was increased to 34 percent.

“The same differences apply to other symptoms such as chills, fatigue, headache, malaise, and muscle aches,” said Matthew Snape.

In April, the study expanded with the participation of more than 1,050 volunteers to test combinations of Moderna and Novavax vaccines with AstraZeneca and Pfizer.