As the United States marked another grim milestone Thursday with more than 4,000 covid-19 deaths reported in a single day, federal disease trackers said research suggests that people without symptoms transmit more than half of all cases of the novel coronavirus.
The findings, which came from a model developed by the Centers for Disease Control and Prevention, demonstrate the importance of following the agency’s guidelines about wearing a mask and maintaining social distance, officials said. The emergence of a more contagious variant of the virus, first detected in the United Kingdom and discovered in eight U.S. states by Thursday, places the federal agency’s conclusion about how the virus is spreading in even starker relief.
“Those findings are now in bold, italics and underlined,” said Jay C. Butler, the CDC deputy director for infectious diseases and a co-author of the study published in the journal JAMA Network Open. Continue reading.