All the coronavirus vaccines on our being considered for the US market prevent severe disease and death, that's all anyone needs to know, experts say.
"To make head to head comparisons, they have to be studied at the same time, in head-to-head trials," Adalja said.
That has not happened. Researchers studying the real-world use of Pfizer's and AstraZeneca's vaccines in Britain reported earlier this month that both lowered the risk of hospitalization and death in people 80 and older -- the group by far the most likely to die from infection.
The preprint study done by a team at the University of Bristol found the Pfizer/BioNTech vaccine was 71.4% effective in preventing hospitalizations and the Oxford/AstraZeneca vaccine was 80.4% effective in preventing hospitalizations in patients well into their 80s.