A woman who returned to the US from China with her has returned and spread the coronavirus, which has infected at least 71 people, researchers reported Tuesday.
It began with the elevator ride, researchers reported in the Centers for Disease Control and Prevention journal Emerging Infectious Diseases.
The woman returned to the Heilongjiang province on March 19 from the US tour, a week after the last coronavirus case was diagnosed in the province. She had no symptoms and was tested negative for coronavirus, but was asked to be detained at home.
No one suspected wrongdoing until the passenger suffered a stroke, with no apparent connection to the passenger. He is reportedly at a party with relatives of a neighbor who lives in the same building as the traveler.
When researchers in China finally put together the story, they decided that the traveler had somehow contaminated the elevator in her building. Her downstairs neighbors who used the same elevator were also infected, and she was infected with her mother and her mother’s boyfriend. They went to a party and infected the stroke patient and his son.
The stroke patient and his two sons went to two hospitals. At least 28 people were infected in the first hospital and another 20 were infected when he was taken to a second facility.
When the Chinese Center for Disease Control and Prevention investigated the genetic makeup of the virus found in this new outbreak, they found that it was different from the species previously seen in China. Viruses in patients are genetically identical, or at least very similar, which leads to the belief that the virus originated abroad.
When investigators learned that one neighbor in the case had recently returned from abroad, they re-examined her. She is not currently infected but has antibodies to the virus, which indicates a previous infection. They hired her as A0, which is her first case. “Therefore, we believe that A0 is an asymptomatic carrier and that B1.1 (her neighbors) are infected with the surfaces of the elevator in the building where they both lived,” they wrote. All the other occupants of the building were tested negative.
“By April 22, 2020, A0 was asymptomatic, and a total of 71 SARS-CoV-2-positive cases were identified in the cluster,” the researchers wrote.
“Our results illustrate how SARS-CoV-2 infection, which does not have the same symptoms, can cause widespread community transmission.”