FThe first doses of the Oxford AstraZeneca or Pfizer BioNTech coronavirus vaccines along with the second doses of the Moderna or Novavax vaccines will generate robust immune responses against Covid-19, researchers have found.
According to the study, participants who received a first dose of the Oxford of Pfizer vaccine generated a robust immune response when they received a second dose of vaccines made by Novavax or Moderna nine weeks later.
The Com-COV study led by the University of Oxford found that no safety concerns were raised in this study involving 1,070 participants.
The researchers say the study supports the flexible use of these vaccines in primary immunization schedules, which is crucial to help their rapid deployment, especially in low- and middle-income countries where vaccine supplies may be available. be irregular.
Encouragingly, all of these regimens generated higher antibody concentrations than the approved and effective two-dose Oxford / AstraZeneca regimen.
Matthew Snape, associate professor of pediatrics and vaccinology at the University of Oxford, and chief investigator of the trial, said: “Thanks to such studies, we are now getting a more complete picture of how different vaccines Covid-19 can be used. together in the same immunization schedule.
“It is encouraging to see that all of these schedules generated higher antibody concentrations than the approved and effective Oxford / AstraZeneca two-dose schedule.
“Regarding cellular immunity, having a first dose of the Oxford / AstraZeneca vaccine followed by one of the other vaccines under study generates a particularly robust response. “
Research found that the Oxford programs followed by Moderna / Novavax both induced higher antibody and T cell responses than the licensed and highly effective Oxford standard two-dose program.
Pfizer / Moderna induced higher antibody and T cell responses than the standard two-dose Pfizer regimen.
And Pfizer / Novavax induced higher antibodies than the two-dose Oxford regimen, which induced weaker antibody and T-cell responses than the two doses of Pfizer.
The researchers also looked at vaccine responses to different variants of the coronavirus.
Blood samples taken from the participants were tested for efficacy against wild-type, beta, and delta variants.
Although it was observed that the efficacy of vaccines against variant strains had decreased, this was a consistent trend across mixed schedules.
The study, published in The Lancet, also found that a significantly higher number of short-lived vaccine reactions were reported in volunteers who received a second dose of Moderna compared to those who received two doses of the injections. from Oxford or Pfizer.