Three new real-world UK studies highlight the effectiveness of one or two doses of the Pfizer/BioNTech or AstraZeneca/Oxford COVID-19 vaccines in preventing both symptomatic and asymptomatic infections and related hospitalizations, with one study showing an effectiveness above 90% for only one dose of the Pfizer vaccine.Up to 85% effective after two dosesIn the first study, an interim analysis of the ongoing SARS-CoV-2 Immunity and Reinfection Evaluation (SIREN) study, was published late last week in The Lancet.
Public Health England Colindale researchers in London enrolled 23,234 adult healthcare workers from 104 public hospitals in England starting Dec 7, 2020, the day before the UK vaccine rollout began.Thirty-five percent of enrollees