medrxiv | Motivated by the rapid spread of a novel coronavirus (2019-nCoV) in
Mainland China, we use a global metapopulation disease transmission
model to project the impact of both domestic and international travel
limitations on the national and international spread of the epidemic.
The model is calibrated on the evidence of internationally imported
cases before the implementation of the travel quarantine of Wuhan. By
assuming a generation time of 7.5 days, the reproduction number is
estimated to be 2.4 [90% CI 2.2-2.6]. The median estimate for number of
cases before the travel ban implementation on January 23, 2020 is 58,956
[90% CI 40,759 - 87,471] in Wuhan and 3,491 [90% CI 1,924 - 7,360] in
other locations in Mainland China. The model shows that as of January
23, most Chinese cities had already received a considerable number of
infected cases, and the travel quarantine delays the overall epidemic
progression by only 3 to 5 days. The travel quarantine has a more marked
effect at the international scale, where we estimate the number of case
importations to be reduced by 80% until the end of February. Modeling
results also indicate that sustained 90% travel restrictions to and from
Mainland China only modestly affect the epidemic trajectory unless
combined with a 50% or higher reduction of transmission in the
community.
