Officials in Provincetown, Massachusetts say they are on their way to containing a COVID-19 outbreak tied to Fourth of July celebrations.
According to Town Manager Alex Morse, the number of active cases has fallen to 59. In all, more than 900 cases have been tied to the outbreak, which CDC officials say helped prompt them to change federal mask guidelines for the vaccinated. Just seven of the people have been hospitalized, officials said.
CDC Director Rochelle Walensky said the low hospitalization numbers are proof that vaccines are working.
"Our vaccines did exactly what they were supposed to do: prevent severe disease, hospitalization and death," she said.
An internal CDC document obtained by NBC News last month cited preliminary data suggesting that the delta variant is as contagious as the chickenpox, and even able to spread among vaccinated people.
An investigation by the state's public health department, which was cited in the CDC report, found that those who were vaccinated were transmitting the virus to other vaccinated people.