America’s top infectious disease doctor said a new study proves conclusively that the coronavirus can spread from one person to another even before symptoms appear.
The study, conducted by German researchers and published Thursday night, found five instances in which the virus was transmitted by people while they were asymptomatic. The discovery confirms what Chinese researchers have previously claimed, although authorities in the United States have debated whether that was true.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said that after the German report, he is certain the illness can spread from people who don’t appear to be sick.
“There’s no doubt after reading this paper that asymptomatic transmission is occurring,” Fauci said. “This study lays the question to rest.”
Asymptomatic spread makes the virus far more dangerous, as it is impossible to know that a person has the virus without symptoms, which include coughing and flu-like conditions.
The revelation may also create more stringent control measures. On Friday, the U.S. government decided to order a two-week quarantine for the 195 passengers who were rushed out of Wuhan, China, where the virus developed. It was the first such decision in 50 years and highlights the concern that the illness has brought.
As of Friday, the virus had infected nearly 10,000 people across the globe and killed 213, most of whom were in mainland China. Despite those numbers, a study warned that the actual number of those infected could be closer to 75,000.
The World Health Organization declared the outbreak a global public health emergency, and the Centers for Disease Control and Prevention announced Thursday that there has been a confirmed case of human-to-human transmission in the U.S.
