The characteristics of and responses to the two COVID-19 outbreak waves in Hebei Province of China, January 2020 to February 2021

Abstract

Hebei Province was affected by two coronavirus disease 2019 (COVID-19) outbreak waves during the period 22 January 2020 through 27 February 2020 (wave 1) and 2 January 2021 through 14 February 2021 (wave 2). To evaluate and compare the epidemiological characteristics, containment delay, cluster events and social activity, as well as non-pharmaceutical interventions of the two COVID-19 outbreak waves, we examined real-time update information on all COVID-19-confirmed cases from a publicly available database. Wave 1 was closely linked with the COVID-19 pandemic in Wuhan, whereas wave 2 was triggered, to a certain extent, by the increasing social activities such as weddings, multi-household gatherings and church events during the slack agricultural period. In wave 2, the epidemic spread undetected in the rural areas, and people living in the rural areas had a higher incidence rate than those living in the urban areas (5.3 vs. 22.0 per 1 000 000). Furthermore, Rt was greater than 1 in the early stage of the two outbreak waves, and decreased substantially after massive non-pharmaceutical interventions were implemented. In China's 'new-normal' situation, development of targeted and effective intervention remains key for COVID-19 control in consideration of the potential threat of new coronavirus strains.

Keywords: COVID-19; Hebei Province; two outbreak waves.

Fig. 1.

Spatial distribution of confirmed COVID-19 cases in Hebei Province. Number of confirmed cases in each prefecture-level city of Hebei Province (a) from 22 January 2020 to 27 February 2020 (wave 1), and (b) from 2 January 2021 to 14 February 2021 (wave 2). (c) Number of confirmed cases in each county-level administrative region of Shijiazhuang City.

Fig. 2.

Cumulative incidence rates of COVID-19 in Hebei Province. (a) Cumulative age-specific incidence rates of COVID-19 in waves 1 and 2. (b) Cumulative region-specific incidence rates of COVID-19 in wave 2.

Fig. 3.

Containment delay of COVID-19 cases with a known date of symptom onset during the two waves of COVID-19 outbreak in Hebei Province. Days in abscissa indicates days between the diagnosis date of a certain case and the diagnosis date of the first cases (wave 1: 22 January 2020, wave 2: 2 January 2021).

Fig. 4.

Cluster events associated with weddings in the second wave of COVID-19 outbreak. (a) Transmission network of the wedding-related cluster of undetermined source (n = 166). (b) The largest wedding-related cluster traced back to a collection of six wedding venues (n = 112).

Fig. 5.

COVID-19 cases by date of diagnosis and non-pharmaceutical interventions taken to suppress COVID-19 transmission in Hebei Province.

Fig. 6.

Effective reproduction number (Rt) for COVID-19 outbreak in Hebei Province during wave 1 (a) and wave 2 (b).