Apr 20, 2021 - Health

Swedish health agency: Those under 65 should receive different vaccine than AstraZeneca's for second dose

Picture of a health care worker in Sweden vaccinating an elderly woman
A Swedish woman receiving the Pfizer-BioNTech vaccine. Photo: Fredrik Sandberg/TT News Agency/AFP via Getty Images

The Swedish Health Agency on Tuesday recommended that people under 65 years old who received the first shot of the AstraZeneca coronavirus vaccine should get a different vaccine for the second shot.

Why it matters: There are no definitive studies regarding immune responses when initial and follow-up vaccine doses are different. The agency said that when results on mixing different doses are released they will evaluate whether the recommendation should be changed.

  • Researchers from the University of Oxford in February began a trial where people received a dose of the Pfizer-BioNTech vaccine after a dose of AstraZeneca's or vice versa, per the New York Times. They will analyze the participants' blood to see how they respond to the mixing.

What they're saying: "The recommendation that people under the age of 65 should not be vaccinated with AstraZeneca's vaccine Vaxzevria remains for the time being," the agency said

  • "People under the age of 65 who have already received a dose of Vaxzevria should instead be offered a second dose of so-called mRNA vaccine, such as Pfizer-BioNTech or Moderna."
  • The agency is recommending that those who received their first AstraZeneca dose should receive a second dose of an mRNA vaccine approximately 12–15 weeks after, and no additional booster mRNA dose is required.
  • For people over 65, the benefits of the AstraZeneca vaccine outweigh the risks.
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