A cured coronavirus patient prepares before donating plasma at Hainan Blood Center in Haikou, south China's Hainan Province, Feb. 17, 2020. Cured patients who were infected with the novel coronavirus disease (COVID-19) are called upon to donate plasma as initial results had indicated the effectiveness of convalescent plasma-derived therapeutic products in curing infected patients in severe and critical conditions. Some recovered patients regard the donation as a way to pay back to the society after they received timely and effective treatment. (Photo by Zhang Liyun/Xinhua)