New York (AP) — As more and more people survive the new coronavirus, hospitals want them to line up to donate some blood. Doctors want to use blood plasma from recovered COVID-19 patients to treat the sick, giving them a dose of the immune system antibodies that fight the virus. There’s no proof it works. But doctors around the world are dusting off the century-old treatment, most famously used during the 1918 flu pandemic. Studies are being planned to test blood plasma against regular care in sick patients, and to prevent infections among people at high risk of exposure including health care workers.