“It has been suggested by scientists that, really to get an accurate idea of case fatality rates, you should divide by the number of cases two weeks ago, not the number of cases today,” Dr. Swaminathan said.
The death rate in the United States is about 5 percent. But according to recent data from the C.D.C., there are likely 10 times more infections than are reported. The so-called infection fatality rate — which includes all cases, not just identified cases — may be about 0.6 percent globally, Dr. Swaminathan said.
Reporting was contributed by Rachel Abrams, Livia Albeck-Ripka, Aliza Aufrichtig, Julie Bosman, Alexander Burns, Benedict Carey, Ben Casselman, Stephen Castle, Emily Cochrane, Michael Cooper, Jill Cowan, Steven Erlanger, Richard Fausset, Luis Ferré-Sadurní, Kimiko de Freytas-Tamura, Thomas Fuller, Jenny Gross, Maggie Haberman, Jack Healy, Makiko Inoue, Annie Karni, Isabella Kwai, Ernesto Londoño, Jonathan Martin, Patricia Mazzei, Mark Mazzetti, Giulia McDonnell Nieto del Rio, Jesse McKinley, Sarah Mervosh, Anna Momigliano, Monika Pronczuk, Amy Qin, Adam Rasgon, Motoko Rich, Amanda Rosa, Dana Rubinstein, Nelson D. Schwartz, Dionne Searcey, Ed Shanahan, Eliza Shapiro, Mitch Smith, Jim Tankersley, Sabrina Tavernise, Hisako Ueno, David Waldstein, Caryn A. Wilson, Edward Wong, Sameer Yasir and Karen Zraick.