People who had received a first dose of the Oxford-AstraZeneca COVID-19 vaccine and received an mRNA vaccine for their second dose had a lower risk of infection compared to people who had received both doses of the Oxford-AstraZeneca vaccine. This is shown in a nationwide study performed by researchers at Umeå University, Sweden.
“Having received any of the approved vaccines is better compared to no vaccine, and two doses are better than one,” says Peter Nordström, professor of geriatric medicine at Umeå University. “However, our study shows a greater risk reduction for people who received an mRNA vaccine after having received a first dose of a vector-based, as compared to people having received the vector-based vaccine for both doses.”
