On July 30, the US Centers for Disease Control and Prevention published its latest Morbidity and Mortality Weekly Report. According to the CDC, this report contains the data that resulted in the agency’s decision to once again revise its mask mandate, encouraging people in places with high virus transmission to wear face masks indoors even if they’re fully vaccinated.
The report includes details on the Delta variant and the impact it has on society at this time, including the growing number of cases of breakthrough infections in vaccinated individuals. The report covers one particularly “pivotal discovery” that solidified the CDC’s mask revision decision, namely that fully vaccinated people who contract the Delta variant can also transmit it to other people.
“The masking recommendation was updated to ensure the vaccinated public would not unknowingly transmit virus to others, including their unvaccinated or immunocompromised loved ones,” the CDC explained in its announcement today. The new report concludes that the Delta variant, also called B.1.617.2, is “highly transmissible.”
The new report was put together in conjunction with the Commonwealth of Massachusetts Department of Public Health, according to the CDC, which paid particular attention to a town in the state called Barnstable County. Multiple big events took place in the town this month, leading to 469 new COVID-19 cases among residents.
Of those cases, 74-percent occurred in people who were fully vaccinated and, using testing, the CDC determined that the Delta variant was behind 90-percent of 133 analyzed cases. As a result of this data, the CDC suggests that cities should require mask-wearing indoors, particularly when there’s a large gathering among the public, and especially if the event will involve a large number of people traveling in from elsewhere.