Traveler from the US infects 71 people in China with Covid-19, research finds
A woman returning home to China from the United States brought a coronavirus with her and started an epidemic that ended up infecting at least 71 people, researchers reported on Tuesday.
It all started with an elevator ride, researchers report in the Centers for Disease Control and Prevention’s Emerging Infectious Diseases journal.
The woman returned to Heilongjiang Province after a trip to the United States on March 19, about a week after the diagnosis of the last case of coronavirus in the province. She showed no symptoms and tested negative for the coronavirus, but was asked to quarantine her at home.
No one suspected that something was wrong until a man with no obvious connection to the traveler suffered a stroke. It turns out that he had been to a party with relatives of a neighbor living in the same building as the traveler.
When Chinese researchers finally made up the story, they determined that the traveler must have contaminated the elevator in his building. Her neighbor on the ground floor, who used the same elevator, was also infected, and in turn, she infected her mother and boyfriend. They went to a party and infected the stroke patient and his sons.
The stroke patient and two of his sons went to two hospitals. At least 28 people were infected in the first hospital and 20 others were infected when he was transferred to a second establishment.
When the Chinese Center for Disease Control and Prevention investigated the genetic makeup of the virus found in this new epidemic, they discovered that it was different from the strains previously seen in China. The viruses in the patients were genetically identical or at least very similar, which led them to believe that the virus originated from abroad.
When investigators learned that a neighbor of one of the cases had recently returned from abroad, they tested it again. She was not currently infected but had antibodies to the virus, indicating a previous infection. They designated it A0, which means it was the first case. “Therefore, we believe that A0 was an asymptomatic carrier and that B1.1 (his neighbor) was infected by contact with surfaces in the elevator of the building where they both lived,” they wrote. . The other residents of the building were all tested negative.
“As of April 22, 2020, A0 remained asymptomatic, and a total of 71 cases positive for SARS-CoV-2 had been identified in the cluster,” the researchers wrote.
“Our results illustrate how a single asymptomatic SARS-CoV-2 infection could lead to widespread community transmission.”