A woman inadvertently infected at least 71 people with coronavirus after using the elevator in her high-rise apartment, the researchers believe.
The woman, who had traveled before returning to her home in China’s Heilongjiang province, from a trip to the United States on March 19 – eight days after the area reported no new Covid-19 cases.
She had no symptoms of the disease and was negative for a virus test, but she went on to self-limit anyway, the researchers wrote in the journal Emerging Infectious Diseases.
The woman had not taken the elevator with anyone else – but her downstairs neighbor used it sometime after her.
On March 29, the neighbor’s mother and her friend, who had visited her apartment, went to a party with another group of people. Then, on April 2, one of these group suffered a stroke and was taken to hospital. However, at this point there was no obvious link between him and the traveler and so he was not tested for coronavirus.
The researchers later concluded that the traveler must have infected the elevator in her building. Her neighbor on the ground floor is thought to have contracted the virus while using it, before infecting her mother and boyfriend when they visited her home. The couple then infected the stroke patient and their two sons at the party.
His two sons stuck it in turn taking care of their father, who was taken to a different hospital on April 6th. The stroke patient and his sons later tested positive for cornea, and investigators found that they had infected 28 people in the first hospital, including five nurses and a doctor. Another 20 people continued to be infected at the second hospital.
The friend of the mother of the lower neighbor showed symptoms of Covid-19 and became the first case in the complex that showed positive in the disease.
When the researchers learned that someone in the apartment complex had recently traveled, they tested the traveler again and this time found antibodies, indicating that she had previously had the disease.
Researchers from the Chinese Centers for Disease Control and Prevention wrote: “We believe that [η ταξιδιώτρια] was an asymptomatic carrier and that the neighbor downstairs was infected by contact with surfaces in the elevator of the building where they both lived.
“Our results show how a single asymptomatic SARS-CoV-2 infection could lead to widespread transmission to the community.”