WASHINGTON (AP) — President Joe Biden is betting on millions more rapid, at-home tests to help curb the latest deadly wave of the COVID-19 pandemic. Surging infections are overloading hospitals and threatening to shutter classrooms around the country. But the tests have already disappeared from pharmacy shelves in many parts of the U.S., and manufacturers warn it will take them weeks to ramp up production. That production was slashed after demand for the tests plummeted over the summer. The latest shortage is another painful reminder that the U.S. has yet to successfully manage its testing supplies, let alone deploy them in the type of systematic way that could quickly crush outbreaks in schools, workplaces and communities.