Data from Provincetown, Massachusetts, suggest similar findings. An August report from the US Centers for Disease Control and Prevention (CDC) showed that following large gatherings in the beach town,
nearly three-quarters of 469 new COVID-19 cases that occurred in the state were in vaccinated people2. Both vaccinated and unvaccinated people had comparably low Ct values, indicating high viral loads, and of the 133 samples sequenced, 90% were identified as Delta. The findings prompted the CDC to update its guidance on 27 July and once again
recommend that people in areas of high transmission wear masks indoors.