CDC said 90% for asymptomatic infection once they did measure infection. https://www.aha.org/news/headline/2021-03-29-cdc-authorized-mrna-vaccines-effective-aga

CDC said 90% for asymptomatic infection once they did measure infection. https://www.aha.org/news/headline/2021-03-29-cdc-authorized-mrna-vaccines-effective-against-asymptomatic-infection https://www.aha.org/news/headline/2021-03-29-cdc-authorized-... The change is partly that the effectiveness wanes after a few months and partly that its less effectively again new variants like Delta and Omicron. You can create delta+omicron mRNA vaccines to deal the second problem, but the first problem is much harder--and maybe impossible--to deal with. This is why we had low cases during the summer of 2021. The vaccine mostly worked at stopping the spread. It no longer does.