This recommendation was based on the continuing decline and trajectory of cases, examining the efficacy of the vaccine products available in the US, and our current understanding of how transmission is occurring (i.e., understanding how the virus spreads). It also helps provide a pathway to ‘a new normal’ to indicate that, by taking certain actions, an individual can begin to slowly resume activities they were engaging in pre-pandemic.

This new guidance is based on multiple studies that have shown the profound effectiveness of the vaccines to prevent both COVID-19 disease and transmission in the real world.  For instance, vaccines are 95% effective in preventing symptomatic COVID-19 in roll-out programs in Israel, 90% effective in first-line responders and health care workers in the US, and 97.4% effective against severe disease, even against the B.1.351 and B.117 variants, in Qatar. Moreover, there is ample evidence at this point that vaccines massively reduce asymptomatic infection (and, thereby transmission), from rates of 86% to 92%, across multiple studies. Therefore, if a vaccinated individual is highly protected and highly unlikely to transmit the infection to others after vaccination, lifting masking and distancing requirements for this population makes sense. Moreover, since masks protect the wearer, the unvaccinated will be protected by their own mask in an indoor setting.