Provincetown ‘well on our way’ to containing COVID-19 cluster, town manager says

An indoor mask mandate was issued in Provincetown after the COVID-19 cluster.Christiana Botic for The Boston Globe

The town manager in Provincetown said Monday that his Outer Cape community is making strong progress in fighting a COVID-19 cluster that infected hundreds of people, including many who were fully vaccinated.

“We are well on our way to containment,” Town Manager Alex Morse wrote in a Facebook posting, adding that as of Monday, the total number of active cases among Provincetown residents had decreased to 59.

He said the number of people recovering from the virus each day “far exceeds” the number of new cases being reported.

“We are optimistic this will continue,” he wrote.

According to Morse, the test positivity rate has plummeted from a high of 15 percent on July 15 to a “new low” of 3.3 percent Saturday and 4 percent Sunday.

“A test positivity rate of <5% is considered progress towards cluster containment, while a testing positivity rate of <1% is considered contained,” Morse wrote.

His update Monday followed a CDC report released Friday which indicated that scientists reviewing the Provincetown outbreak made the startling discovery that vaccinated people who become infected can carry as much of the virus as unvaccinated patients.

Officials have put the total number of cases associated with the cluster at around 900, including 231 Provincetown residents.

Most of the infections are from the Delta variant. Authorities have said about three-quarters of the infected people had been vaccinated.

The CDC report looked at 469 COVID-19 cases identified among Massachusetts residents who had traveled to Provincetown between July 3 and July 17, including 346 fully vaccinated people. About 274 of the vaccinated people with so-called breakthrough infections showed symptoms, most commonly cough, headache, sore throat, muscle pain, and fever.

Testing identified the highly contagious Delta variant in 90 percent of specimens from 133 patients.

Public health authorities have continually emphasized that breakthrough infections are rare, and that vaccinated people who contract the virus are unlikely to become severely ill.

“What’s abundantly clear is that the vaccines are working. There were only a few hospitalizations and there were no deaths. In addition, the outbreak came under control quickly,” Sam Scarpino, the managing director of pathogen surveillance at the Rockefeller Foundation, said in an e-mail.

“Given the high case rates across the US, we need to focus on NPIs [non-pharmaceutical interventions], e.g., masking and testing, to ensure that unvaccinated children and individuals with health conditions that prevent vaccination and/or the development of full immunity are protected. However, even against Delta, the vaccines are protecting individuals from severe disease and interrupting transmission,” said Scarpino, who is an affiliate professor at Northeastern University.

Provincetown has one of the state’s highest vaccination rates, with virtually all eligible residents fully vaccinated, state data show. Even though most infections have not led to severe illness, the outbreak has shown that the virus can still raise alarm — and thwart people’s summer plans — in places with high vaccination rates.