By: Kylie E C Ainslie, Caroline Walters, Han Fu, Sangeeta Bhatia, Haowei Wang, Marc Baguelin, Samir Bhatt, Adhiratha Boonyasiri, Olivia Boyd, Lorenzo Cattarino, Constanze Ciavarella, , Zulma Cucunubá, Gina CuomoDannenburg, Amy Dighe, Ilaria Dorigatti, Sabine L van Elsland, Rich FitzJohn, Katy Gaythorpe, Lily Geidelberg, Azra C Ghani, Will Green, Arran Hamlet, Katharina Hauck, Wes Hinsley, Natsuko Imai, David Jorgensen, Edward Knock, Daniel Laydon, Gemma Nedjati-Gilani, Lucy C Okell, Igor Siveroni, Hayley Thompson, Juliette Unwin, Robert Verity, Michaela Vollmer, Patrick GT Walker, Yuanrong Wang, Oliver Watson, Charles Whittaker, Peter Winskill, Xiaoyue Xi, Christl A Donnelly, Neil M Ferguson , Steven Riley

In: Report 11, the WHO Collaborating Centre for Infectious Disease Modelling within the MRC Centre for Global Infectious Disease Analysis, J-IDEA, Imperial College London.

Date: 24 March, 2020

Summary 

• Early social distancing in China may have led to control of COVID-19 transmission.
  • January 2020: strict social distancing in Wuhan (since 23 January).
  • February 2020: peak of 2,000 – 4,000 new confirmed cases per day (early February).
  • March 2020: five consecutive days of no new cases by local transmission (as of 23 March).
• Interventions taken to control transmission have impacted economic productivity.
  • Ability to resume economic activity without restarting the epidemic not yet clear.
• Investigate relationship between transmission and within-city movement.
  • Movement used as a proxy for economic activity.
• Conclusion based on reviewing data for 5 provinces in China, Beijing and Hong Kong:
  • Possible to maintain intermediate levels of local activity without starting a large outbreak.
• Movement and transmission details:
  • Movement statistics from Baidu.
    • Normal = 5 trips per person per day.
    • Sharp decline to 1-2 trips per day after movement restrictions put in place.
  • Correlation between movement and transmission:
    • Initially, strong positive correlation:
      • Decrease in movement = decrease in transmission.
    • As movement resumed, weak negative correlation:
      • Increase in movement = continued decrease in transmission.
    • No correlation for Hong Kong.
  • May indicate ability to maintain economic activity while simultaneously containing COVID-19 effectively.