The man, who worked as a seller of medical products for the elderly, traveled from his home province of Heilongjiang to neighboring Jilin Province and took the virus with him.
According to authorities, he unwittingly transmitted the virus to elderly people for several days before health authorities sought him out as a relative of a confirmed case.
The superproliferation phenomenon occurred in our province mainly because it was still at an early stage of infection when superproliferation was discovered and had a relatively strong ability to shed the virus, Zhao Qinglong, an official at the Jilin Provincial Center for Disease Control and Prevention, told the state news agency Xinhua.
Superproliferation occurs when one person infects a large number of people due to a higher droplet virus load or other factors such as behavior and timing.
The apparent transgression of the Jilin event came at a time when China is grappling with the worst outbreak of the coronavirus in months, with hundreds of reported cases and tens of millions of people trapped in its northern provinces.
It also demonstrated the extent and speed of contact tracing and detection by Chinese health authorities, which has been crucial in containing localised epidemics.
Detailed itinerary and data protection
The vendor was diagnosed Sunday as a confirmed case of Covid-19 after he was initially identified as an asymptomatic carrier last Tuesday, according to the provincial health department in Jilin. In China, asymptomatic infections are reported separately from official cases.
The Commission has published a detailed itinerary of the vendor’s trips in the week before he was tested for the virus, including four train trips (with seat numbers), three bus trips and a subway ride between Heilongjiang and Jilin.
The man led four days of health workshops, or marketing sessions, in health clubs for the elderly in Gongzhuling and Tonghua in Jilin.
A total of 79 people who attended the workshops were infected by 23 of them, Zhang Yan, deputy director of the Commission, said at a press conference on Sunday. The average age of those infected is 63, the oldest 87, Zhang said.
All infected people who have been in close contact with humans have been tracked down and quarantined, followed by positive results from medical surveillance, Zhang said.
While the publication of detailed travel records of coronavirus patients in China is an effective tool for contact tracing, it has also raised privacy concerns.
Last month, a young woman in the southwestern city of Chengdu was publicly pilloried on social media for her decadent lifestyle when users attacked her for going to a bar and several nightclubs two weeks before she tested positive for the virus.
Community health clubs under supervision
The apparent super-prevalence in Jilin has prompted experts and public health authorities to take a closer look at the issue.
A health club in the city of Tonghua is located in a room on the ground floor of a former apartment building, where 30 to 40 people attended the seminar, including a small number of participants wearing masks, reports Xinhua.
The infected people have gathered in a closed area for a long time, Xinhua Zhao, a health worker in Jilin, told Xinhua Zhao. Most of them are middle-aged and elderly people with low immunity and therefore highly susceptible to infections.
Health clubs for the elderly are increasingly common in residential areas in China. Marketing events, often called health talks, are regularly held to promote health products such as dietary supplements and physical therapy equipment.
Unlike cinemas, restaurants, karaoke halls and other commercial establishments, these clubs are often hidden in residential buildings and difficult for authorities to regulate, Xinhua said.
Authorities in Jilin are investigating whether the two health clubs where the man organized actions violated rules, an official from the province’s market supervision bureau said at a news conference.