The agency will also be keeping a close eye on any breakthrough infections that are caused by SARS-CoV-2 variants, some of which have been shown to knock back vaccine efficacy.
The vast majority of people in the US have been vaccinated with one of the mRNA vaccines, made by Moderna and Pfizer-BioNTech, which both had around 95 percent efficacy in Phase III clinical trials.Less than five percent of vaccinated people in the US have received the Johnson & Johnson adenovirus-based vaccine, which had a slightly lower efficacy of 72 percent in the US.
The extraordinary calculation that 99.992 percent of vaccinated people have not contracted the virus may reflect that they all simply have not been exposed to the virus since being vaccinated.“No vaccine is 100 percent efficacious or effective, which means that you will always see breakthrough infections regardless of the efficacy of your vaccine.â€.
That suggests the death rate among breakthrough cases is around one percent and, among all fully vaccinated people, around 0.0001 percent.