Fourth mRNA vax dose may elicit better response than third

A fourth dose of mRNA coronavirus vaccine boosts antibodies and other immune responses to higher levels than seen after the third dose, according to UK trial data.
Researchers recruited 166 adults who had received a booster dose of the Pfizer-BioNTech mRNA vaccine after two doses of either AstraZeneca’s viral vector vaccine or initial inoculation with Pfizer-BioNTech’s shots.
They were randomly assigned to receive either another Pfizer-BioNTech shot or Moderna’s mRNA booster as a fourth dose.
Half of the participants were older than 70, and the average interval since the third shot was seven months.