WASHINGTON (AP) — When a Halloween party sparked a COVID-19 outbreak at North Carolina Agricultural and Technical State University, school officials conducted rapid screening on more than 1,000 students in a week, including many who didn't have symptoms.

Although such asymptomatic screening isn't approved by regulators and the 15-minute tests aren't as sensitive as the genetic one that can take days to yield results, the testing director at the historically Black college credits the approach with quickly containing the infections and allowing the campus to remain open.

"Within the span of a we...