Risk assessment of novel coronavirus COVID-19 outbreaks outside China

Peter Boldog; Tamas Tekeli; Zsolt Vizi; Attila Denes; Ferenc Bartha; Gergely Rost

The starting point of our transmission model is 23 January, when major cities in Hubei province were closed [7] . From this point forward, we run a time dependent SE n I m R model in China outside Hubei, which was calibrated to be consistent with the estimated case numbers outside Hubei until 31 January. We impose time dependence in the transmission parameter due to the control measures progressively implemented by Chinese authorities on and after 23 January. With our baseline R 0 = 2.6, disease control is achieved when more than 61.5% of potential transmissions are prevented. We introduce a key parameter t * to denote the future time when control measures reach their full potential. For this study we assume it to be in the range of 20-50 days after 23 January. Using our transmission model, we calculate the total cumulative number of cases (epidemic final size) outside Hubei, for each t * in the given range. This also gives an upper bound for the increasing cumulative number of cases C = C(t).