delta variant is fueling infection surges. The authors said the findings suggest the CDC's mask guidance should be expanded to include the entire country, even outside of hot spots.
The findings have the potential to upend past thinking about how the disease is spread. Previously, vaccinated people who got infected were thought to have low levels of virus and to be unlikely to pass it to others.
But the new data shows that is not the case with the delta variant. The outbreak in Provincetown — a seaside tourist spot on Cape Cod in the county with Massachusetts’ highest vaccination rate — has so far included more than 900 cases.