Tanks of liquid oxygen and tents for Covid-19 patients at the Hospitals of Providence Sierra in El Paso, Texas.Credit…Joel Angel Juarez for The New York Times Alex M. Azar II, the secretary of health and human services, on Capitol Hill in October.Credit…Michael A. McCoy for The New York Times Federal health officials on Tuesday provided the most detailed projections to date about when a wider swath of Americans may be able to begin to receive Covid-19 vaccines, once any is authorized, and treatments outside of an experimental setting, and about what that could look like. People deemed highest priority — perhaps health care workers or nursing home residents — could be vaccinated in December, with more widespread vaccination to come in the first months of next year, the officials said, laying out an ambitious timeline that could well be thwarted by delays. The forecasting follows two encouraging developments on […]