Effective control of SARS-CoV-2 transmission in Wanzhou, China

Qiuling Shi1,2, Yaoyue Hu1, Bin Peng1, Xiao-Jun Tang1, Wei Wang1, Kun Su3, Chao Luo4, Bo Wu4, Fan Zhang1, Yong Zhang1, Benjamin Anderson5, Xiao-Ni Zhong1, Jing-Fu Qiu6, Cheng Yong Yang7, Ai-Long Huang8

  1. School of Public Health and Management, Chongqing Medical University, Chongqing, China.
  2. State Key Laboratory of Ultrasound in Medicine and Engineering, Chongqing Medical University, Chongqing, China.
  3. Center for Disease Control and Prevention, Chongqing, China.
  4. Wanzhou District Center for Disease Control and Prevention, Chongqing, China.
  5. Global Health Research Center, Duke Kunshan University, Kunshan, China.
  6. School of Public Health and Management, Chongqing Medical University, Chongqing, China. jfqiu@126.com.
  7. Ausper Biopharma, Hangzhou, China. thechrisyang@gmail.com.
  8. Key Laboratory of Molecular Biology on Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China. ahuang@cqmu.edu.cn.

Abstract

The effectiveness of control measures to contain coronavirus disease 2019 (COVID-19) in Wanzhou, China was assessed. Epidemiological data were analyzed for 183 confirmed COVID-19 cases and their close contacts from five generations of transmission of severe acute respiratory syndrome coronavirus 2 throughout the entire COVID-19 outbreak in Wanzhou. Approximately 67.2% and 32.8% of cases were symptomatic and asymptomatic, respectively. Asymptomatic and presymptomatic transmission accounted for 75.9% of the total recorded transmission. The reproductive number was 1.64 (95% confidence interval: 1.16-2.40) for G1-to-G2 transmission, decreasing to 0.31-0.39 in later generations, concomitant with implementation of rigorous control measures. Substantially higher infection risk was associated with contact within 5 d after the infectors had been infected, frequent contact and ≥8 h of contact duration. The spread of COVID-19 was effectively controlled in Wanzhou by breaking the transmission chain through social distancing, extensive contact tracing, mass testing and strict quarantine of close contacts.

Presented By Yaoyue Hu | ORCID iD

COVID-19, MedicineNicholas Liao2021-01 (Jan)