The Lancet on Monday, researchers observed patients both vaccinated and unvaccinated who tested positive for COVID-19 between April 1 to June 6, 2021 in Scotland, where the Delta variant has become dominant. RELATED: COVID Delta variant prevalent, vaccinations stall Pfizer’s vaccine "offered very good protection: 92% (95% CI 90–93) S gene-negative, 79% (75–82) S gene-positive.
Protection associated with ChAdOx1 nCoV-19 (Oxford–AstraZeneca vaccine) was, however, substantial but reduced: 73% (95% CI 66–78) for S gene-negative cases versus 60% (53–66) for those S gene-positive," according to The Lancet.
Authors of The Lancet study noted further research needs to be done for more accurate percentage estimates on both vaccines’.