Impact of vaccination on household transmission of SARS-COV-2 in England
Data review (552,984 residential households where there was at least one case of COVID-19) found that where the positive case had had the COVID-19 vaccine >21 days previous (Pfizer or AZ), there was an approximately 50% reduction in the rate of secondary infection cases.
Source:
Public Health England
SPS commentary:
This is also summarised in a press release.
The rate of secondary household cases of infection was 10.1% for those unvaccinated, 5.72% for those that had had the AZ vaccine, and 6.25% for those that had had the Pfizer vaccine (unadjusted OR of 0.55 [95%CI 0.46-0.67] and 0.57 [0.49-0.65]).