A comprehensive description of the clinical features of virus and the approach to transmission control in Shanghai
As of 12 p.m. on Feb. 29, Shanghai has seen a total of 337 confirmed cases and 3 deaths of COVID-19, significantly lower than what many expected.
Since the COVID-19 outbreak, some researchers have listed Shanghai as the most dangerous Chinese city besides Hubei due to its large immigrant community and high population density.
COVID-19, like other highly contagious diseases, can lead to exponential growth in the number of infected cases, which will be devastating to any city in the world. Indeed, for Shanghai, a city with 30 million residents, the consequence would be unthinkable if the virus could spread freely across the city.
To share Shanghai’s experience with the rest of the world and prevent any widespread outbreak, Zhang Wenhong from Fudan affiliated-Huashan Hospital, Lu Hongzhou from Fudan affiliated-Shanghai Public Health Clinical Center, etc. published a preprint titled “A descriptive study of the impact of diseases control and prevention on the epidemics dynamics and clinical features of SARS-CoV-2 outbreak in Shanghai, lessons learned for metropolis epidemics prevention” on behalf of the Shanghai Clinical Treatment Expert Group for COVID-19 on Feb. 24. (https://doi.org/10.1101/2020.02.19.20025031)
The paper says, based on a statistical analysis performed by the Expert Group, the COVID-19 patients in Shanghai demonstrated an incubation period for COVID-19 at 6.438 days and 9.6% of them were severe cases. The median time for COVID-19 progressing to severe diseases was 8.5 days and most COVID-19 severe cases progressed within 14 days of disease onset.
The authors point out, currently the severity of the patients are classified based on their respiratory system and oxygenation. However, the experts observed multiple abnormalities of the body before the emergence of respiratory problems. For example, CD4 and CD8 cells responsible for the mediation of protective immune responses both decreased in COVID-19 patients, and up to 15% of the patients had CD4 /CD8 ratio lower than 1, which indicates a very weak immune system. The experts believe medics should keep an eye on the functions of other organs apart from the respiratory system .
Photo credit: WeChat of Infectious Diseases Department of Huashan Hospital (华山感染)
Shanghai’s main methods to control the virus transmission, according to the paper, include shutting down all large public venues, reducing passenger flows and advertising individual protective measures on a large scale. According to the preprint, the actual transmission rate within Shanghai is found to have decreased more than 95% compared with the previously reported predictions by some researchers. The authors believe, this suggests that Shanghai has been effectively containing the COVID-19 outbreak.
The full text of the preprint is available from https://www.medrxiv.org/content/10.1101/2020.02.19.20025031v1.full.pdf
Editor: Deng Jianguo
