A nationwide cohort study from Sweden finds that people who got an Oxford-AstraZeneca vaccine dose in combination with a Pfizer or Moderna vaccine dose have more protection against infection than people who just received two doses of Oxford-AstraZeneca.
For this study, researchers analyzed data on 721,787 persons, 430,100 of whom received two doses of the Oxford-AstraZeneca vaccine, and 110,971 received one dose of Oxford-AstraZeneca, and later received a dose of an mRNA vaccine. All participants were followed for up to 183 days.
Having analyzed all collected data, scientists made the following conclusions:
- Unvaccinated people had more than 3.5 times higher risk to contract a SARS-CoV-2 infection than vaccinated people
- Oxford-AstraZeneca vaccine provided 50% protection against infection
- Oxford-AstraZeneca vaccine followed by a Pfizer vaccine dose was 67% effective against infection
- Oxford-AstraZeneca vaccine followed by a second dose of Moderna had 79% protection against infection.