Epidemiological Characteristics of COVID-19 under Government-Mandated Control Measures during January–February 2020 in Inner Mongolia, China

The coronavirus disease 2019 (COVID-19) pandemic has had severe health impacts worldwide. We aim to provide suggestions to the government for managing serious infectious disease outbreaks in remote regions having relatively poor medical resources. Basic reproduction number (R0), incubation period, time from symptom onset to confirmation, and duration of hospitalization were analyzed. We compared the compositions of imported and local secondary cases and cases with mild/common and severe/critical illnesses according to age, sex, and clinical symptoms. From January 23 to February 19, 2020 (less than one month), 75 local COVID-19 cases were confirmed in Inner Mongolia. Among these, the median age was 45.0 years, and 33 (44.0%) were imported cases. More than 80.0% cases had mild/common illness. The case fatality rate was 1.3%, and R0 was estimated to be 2.3. The median incubation period was 8.5 days. There was a significant difference in the incubation period between imported and local secondary cases (P < 0.001). Early and mandatory control strategies implemented by the government were associated with a rapid reduction in COVID-19 incidence in Inner Mongolia.