Another study, this time Swedish, shows that combining different vaccines against coronavirus - that is, administering the next dose with a different vaccine than the initial dose - is highly effective in terms of immune protection.
the new study shows a 79% and 67% reduction in the risk of coronavirus infection for those who took the second dose with Moderna or Pfizer respectively while taking the first dose with AstraZeneca
People who took the first dose of the Oxford-AstraZeneca vaccine and then the second dose of the Pfizer / BioNTech or Moderna mRNA vaccine had a lower risk of coronavirus infection than those who took both doses of AstraZeneca, according to the study. .
The researchers, led by Peter Nordstrμm, a professor of geriatrics at Umeα University, who published the paper in the medical journal The Lancet Regional Health - Europe, analyzed data on about 700,000 people, at a time when the Delta variant of the virus dominated.
As Dr. Nordstrτροm stated, “either vaccine is better than any other vaccine and both doses are better than one. "But our study shows that there is a greater reduction in the risk of infection for people who got the mRNA vaccine after the first dose with a more traditional vaccine like AstraZeneca, compared to those who did both doses with the last one."
At a time of 2.5 months after the second dose, the new study shows a 79% and 67% reduction in the risk of coronavirus infection for those who took the second dose with Moderna or Pfizer respectively while taking the first dose with AstraZeneca. Those who had taken both doses of AstraZeneca had a 50% reduction in the risk of infection (the reduction in the risk of disease, serious illness and death was much greater).
All studies to date have shown that mixing different vaccines elicits a strong immune response, which is important in view of a third booster dose, especially for those who have not had a mRNA vaccine in the first two doses.
The World Health Organization has stated that despite all the encouraging results regarding the effectiveness of mixing different vaccines, more studies are needed and the Swedish one is such a reassuring study.