How did public health interventions affect the spread of COVID-19 in China outside of the Hubei province, and how will relaxing these interventions contribute to a second wave of COVID-19 cases?

Bottom Line:

Mathematical modeling data shows that massive public health measures have substantially decreased the spread of COVID-19 throughout China, but relaxation of these measures and the introduction of imported international cases could lead to a second wave of COVID-19 infections.


Leung, K. et al. First-wave COVID-19 transmissibility and severity in China outside Hubei after control measures, and second-wave scenario planning: a modelling impact assessment. The Lancet (2020). DOI: 10.1016/S0140-6736(20)30746-7

Date Published:

8 April 2020


Nationwide public health interventions (e.g. domestic travel restrictions, shutdown of non-essential services) were implemented throughout China beginning on January 23, 2020 to slow down the spread of COVID-19. To see how these interventions have impacted the spread of COVID-19 over time, researchers have estimated the instantaneous reproduction number (Rt), which is a measure of virus transmissibility. Their data shows that Rt has fallen below 1 since aggressive public health measures were introduced, meaning that the epidemic is slowing its rate of spread. The researchers also estimated the confirmed case-fatality risk (cCFR), which is a measure of disease severity. They found the cCFR to be 0.98% outside of Hubei, and 5.91% within Hubei. Finally, the researchers used mathematical modeling to determine the impact that relaxation of public health interventions and a growing number of internationally-imported cases will have on the number of COVID-19 cases. The model showed that a longer duration of relaxed interventions was exponentially associated with an increased number of cases over time. The findings from this study will help inform future policies that will be required to mitigate a second wave of COVID-19 infections in China.

Summary by: Louis Huynh