An outbreak of COVID-19’s delta variant in Provincetown, Massachusetts following the Fourth of July spawned several alarming headlines after it was referenced in a leaked document from the Centers for Disease Control and Prevention detailing why it changed its indoor mask guidance for vaccinated individuals.
“Vaccinated people made up three-quarters of those infected in a massive Massachusetts covid-19 outbreak, pivotal CDC study finds,” read a widely shared headline and tweet from the Washington Post.
“‘It’s Nowhere Near Over’: A Beach Town’s Gust of Freedom, Then a U-turn,” reads a similar headline from the New York Times.
The study found that vaccinated individuals who do contract the delta variant have as much virus in their noses as infected unvaccinated individuals (which points towards vaccinated individuals being able to transmit the virus), and the authors state that “jurisdictions might consider expanded prevention strategies” such as new mask mandates and business closures to combat the spread of the delta variant.
While the study caused panic on some corners of the internet, Alex Morse, Provincetown’s town manager, said the study and the coverage of the Cape Cod town’s outbreak lacked important context.
“The vaccines are working,” he tweeted. “Of the 900 cases related to the Provincetown cluster, there have been no deaths, 7 hospitalizations, and the symptoms are largely mild. Our positivity peaked at 15% on 7/15 and was only 4.8% yesterday. The outbreak is contained and Provincetown is safe.”
The Provincetown outbreak reinforces what is already known: Vaccinated individuals are at very low risk of severe disease from the delta variant. The CDC estimates that nationally, just 0.002% of vaccinated individuals have suffered severe breakthrough cases.
In highly vaccinated areas like Provincetown (local data was unavailable but Massachusetts has the second-highest vaccination rate in the country at 69% of eligible residents fully vaccinated), case increases will become largely decoupled from an increase in hospitalizations and deaths.
The study did not try to answer the question of how many people in the area could have possibly been infected, which would have helped answer the question of how common breakthrough infections are. However, the study makes clear that if a breakthrough infection occurs, it is highly unlikely to lead to severe disease.
“Indoor masking is helpful during a spike but not a sustainable long term solution,” Morse wrote. “Vaccination is. More and more businesses here are mandating employee and customer vaccination.”