CDC Investigation of Provincetown Outbreak Prompts New Mask Recommendations
The outbreak of COVID-19 in Provincetown directly informed a decision by the Centers for Disease Control and Prevention to tighten its mask guidance this week, the federal agency said Friday.
In a new report, the CDC outlined its Provincetown investigation, conducted in concert with the Massachusetts Department of Public Health, Barnstable County, and other local partners.
The report suggests that even in communities without substantial rates of COVID-19 transmission, jurisdictions “might consider” expanding prevention measures, such as the wearing of masks in indoor public settings, regardless of vaccination status.
A mandate or recommendation along those lines would be stricter than the CDC guidance issued Tuesday, which said people should wear masks indoors in public settings in areas of substantial or high transmission.
Erika Woods, deputy director of the Barnstable County Department of Health and Environment, told CAI the Provincetown outbreak shows that the Delta variant, detected in 90% of specimens from 133 patients in the study, is highly virulent and easily transmissible.
“So just because someone is vaccinated does not mean they can't transmit the Delta variant, and likely not the other variants as well,” she said. “So I think it's one of those things where we just have to realize that even if we are vaccinated, we're not bulletproof.”
In a written statement, Dr. Rochelle Walensky, director of the CDC, said the investigation showed the Delta variant produced high viral loads, regardless of whether or not a person was vaccinated.
High levels of virus suggested a higher risk of transmission and raised concern that vaccinated people can transmit the Delta variant, unlike with other variants, according to Walensky.
“This finding is concerning and was a pivotal discovery leading to CDC’s updated mask recommendation,” she said.
The report acknowledged the role of travel and large public gatherings in the outbreak and said event organizers and local health officials should assess whether limiting capacity at gatherings or postponing events may be warranted.
As of Thursday, 882 confirmed cases had been tied to the Provincetown cluster that started around the Fourth of July. The cases included 531 Massachusetts residents, 220 of whom live in Provincetown.
The CDC reviewed 469 Massachusetts cases among people who were in Provincetown between July 3 and 17. Of those cases, nearly three-quarters occurred in people who were fully vaccinated.
Walensky thanked state and local collaborators for their work on the investigation.
“I would also like to humbly thank the residents of Barnstable County who leaned in to assist with the investigation through their swift participation in interviews by contact tracers, willingness to provide samples for testing, and adherence to safety protocols following notification of exposure,” she said.