Harvard study found that vaccinations alone aren’t enough to fight COVID-19 - PolitiFact

… The study's conclusion was not that vaccinations don't impact infection, but that steps such as masking and social distancing should be used along with vaccination to fight the pandemic...

https://www.politifact.com/factchecks/2021/oct/19/youtube-videos/harvard-study-found-vaccinations-alone-arent-enoug/