Nanjing, capital city of Jiangsu province, last week launched citywide nucleic acid testing for Covid-19 after 17 cleaning workers at Nanjing Lukou International Airport tested positive. Experts suspect that the small-scale outbreak arose form an imported case. The risk level of four residential communities and villages near the airport was raised to medium-level. The more than 9 million residents of Nanjing have been immediately tested over the course of a few days. A negative test taken within 48 hours is required for departure from Nanjing airport and at railway and highway stations in the city, and all public transportation has been suspended in the medium-risk regions. Infections of airport staff previously occurred at Shenzhen Bao'an International Airport in June and Shanghai Pudong International Airport in November 2020, where the cases were all found to be associated with international flights.
The airport outbreak in Nanjing is highly likely to be related to imported cases, Fang Zhongyou, Director of the Nanjing Municipal Health Commission, said at a press conference. But he noted that further investigation is still needed to identify the source and transmission route of the virus. Airport workers are tested on a regular basis as one of the city’s routine measures to prevent and control the spread of Covid-19. Cities near Nanjing, such as Suzhou, Wuxi and Xuzhou, have ordered all residents who traveled to Nanjing in the past 14 days to immediately report to health authorities for testing. To trace the source of the latest outbreak, Nanjing has formed an epidemiological investigation team consisting of more than 1,500 people, including health workers and public security officers.
Nanjing launched a second round of citywide nucleic acid testing for its residents and visitors on July 25, as five provinces in China have reported cases related to the Nanjing outbreak. In the city's first round of testing, involving 9.2 million people, a total of 57 positive cases were found. All the confirmed cases were related to the airport. As of July 25, Nanjing had detected 75 confirmed and 13 asymptomatic cases. The areas reporting cases linked to the Nanjing outbreak are Zhongshan in Guangdong province, Mianyang in Sichuan province, Hexian county and Wuhu city in Anhui province and Shenyang in Liaoning province. The outbreak in Nanjing is likely to last at least another two weeks. Nanjing has set up 1,452 sample collection centers and 76 institutions that have analyzed a maximum of 3.5 million samples a day.
Nearly all Covid-19 cases in the latest outbreak in Nanjing were vaccinated, but experts emphasized that the vaccines are still effective in avoiding serious illness and hospitalization. One non-vaccinated case was under 18 years old. All cases had comparatively milder symptoms and have a lower chance of deterioration into severe cases. About 90% of the staff at the airport in Nanjing, or 5,036 people, had received vaccines as of May.
China rejected a request of the World Health Organization (WHO) to conduct a second study on the origins of Covid-19 in the country. Chinese authorities said the request was politicizing Covid-19 origin studies, which should remain strictly scientific and include other countries besides China, some of which have identified Covid-19 cases before the first case in China was reported on December 8, 2019. Over 13 million people signed an online petition demanding the WHO investigate the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) at Fort Detrick, Maryland, to look for a possible leak of the coronavirus. Investigating Fort Detrick is the call of people all over the world, including the Chinese people and it is a question that the U.S. must answer when it comes to the origin of Covid-19, and a problem it can never circumvent, the Chinese Foreign Ministry said. Zeng Yixin, Deputy Director of the National Health Commission, said that it is impossible for China to accept the WHO's plan, which lacks respect for common sense and is arrogant toward science. China is willing to participate in a second-phase study but wants it to be carried out in other countries besides China.
The Wuhan Institute of Virology (WIV) has never engineered or leaked the novel coronavirus and no staff members have ever contracted the virus, Yuan Zhiming, Director of the National Biosafety Laboratory in Wuhan, Hubei province, said. The WIV had not come in contact with, preserved or researched the virus before December 30, 2019, he added. “Since the laboratory began operating in 2018, no laboratory leaks or human infection incidents have ever happened.”
Indications that the coronavirus was circulating in Europe months before China officially confirmed the first case in Wuhan have been revived by a new study of blood samples collected in Italy as early as October 2019. Cancer researchers at the Istituto Nazionale dei Tumori in Milan reported that new tests of pre-pandemic blood samples at two laboratories were found to have antibodies associated with the Covid-19 infection. The WHO asked for further testing to be carried out, and the samples were sent to the VisMederi laboratory in Siena, Italy, and to a facility at Erasmus University in the Netherlands, affiliated with the WHO. Marion Koopmans, head of virology at Erasmus University, said the new research may not be conclusive. She said results from the new study were “interesting”, but according to the university’s strict criteria, none of the samples provided conclusive proof of prior Covid-19 infection.
According to a report by Chinese researchers, the coronavirus can spread through frozen food products and global efforts are needed to prevent cold chain transmission and step up information sharing in the field. The conclusion was based on epidemiological evidence related to two infected dock workers in the coastal city of Qingdao, Shandong province, who were identified in September during routine testing. The defining piece of evidence was that traces of live virus had been detected on frozen cod packaging that had been handled by the workers, the first time in the world living coronavirus was isolated from food packaging, the report said. It added that the study confirmed that imported cold chain products were contaminated with relatively high loads of SARS-CoV-2 through cold chain processing and “the virus can spread across countries and regions over long distances through the international marine fishery trade”. The report was published online by China CDC Weekly, an academic platform established by the Chinese Center for Disease Control and Prevention.
