Epidemic and control of COVID-19 in Niger: quantitative analyses in a least developed country

Abstract

Background: The COVID-19 pandemic is challenging the public health response system worldwide, especially in poverty-stricken, war-torn, and least developed countries (LDCs).

Methods: We characterized the epidemiological features and spread dynamics of COVID-19 in Niger, quantified the effective reproduction number (R_t ), evaluated the impact of public health control measures, and estimated the disease burden.

Results: As of 4 July 2020, COVID-19 has affected 29 communes of Niger with 1093 confirmed cases, among whom 741 (67.8%) were males. Of them 89 cases died, resulting in a case fatality rate (CFR) of 8.1%. Both attack rates and CFRs were increased with age (P < 0.0001). Health care workers accounted for 12.8% cases. Among the reported cases, 39.3% were isolated and treated at home, and 42.3% were asymptomatic. 74.6% cases were clustered in Niamey, the capital of Niger. The R_t fluctuated in correlation to control measures at different outbreak stages. After the authorities initiated the national response and implemented the strictest control measures, R_t quickly dropped to below the epidemic threshold (<1), and maintained low level afterward. The national disability-adjusted life years attributable to COVID-19 was 1267.38 years in total, of which years of life lost accounted for over 99.1%.

Conclusions: Classic public health control measures such as prohibition of public gatherings, travelling ban, contact tracing, and isolation and quarantine at home, are proved to be effective to contain the outbreak in Niger, and provide guidance for controlling the ongoing COVID-19 pandemic in LDCs.

Figure 1

Geographical distribution and spatial clustering of COVID-19 cases in Niger. Thematic map shows the commune-level attack rate of COVID-19 in Niger. Areas highlighted with red or pink edging represent most likely cluster area and secondary likely cluster area, respectively.

Figure 2

Age and gender differences in incidence and fatality of COVID-19 in Niger. Panel A. The attack rate (AR) and case fatality rate (CFR). Panel B. AR of symptomatic cases (left) and asymptomatic cases (right). Panel C. CFR in Niamey (left) and other regions (right).

Figure 3

Epidemic curve and estimated effective reproduction number (R_t) during the COVID-19 outbreak in relation to public health control measures in Niger. Panel A. Epidemic curve (symptom onset and report date) of cases. Panel B. Estimated R_t in relation to public health control measures. Values represent average R_t (central dark blue line) and associated 95% confidence interval (light blue shade), by date of symptom onset. The critical value of R_t = 1 is marked with a horizontal dot line, below which sustained transmission is impossible. Triangles at the bottom represent the moment of important public health control measures: (1) The practice of social distancing in Niamey (17 March 2020); (2) The Ministry of Public Health announced the first COVID-19 case in Niger, and the authorities developed the national COVID-19 Emergency Preparedness and Response Plan (19 March 2020); (3) Targeted control measures have been implemented in Niamey and throughout the country, such as closure of places of worship, health screenings and border control, banned on non-essential visits to remand centers, quarantine at home and establishment of temporary hospitals (20 March 2020); (4) The authorities declared the state health emergency (27 March 2020); (5) Travel ban and Curfew in Niamey (28 March 2020); (6) Lockdown of Niamey (29 March 2020); (7) Reopened places of worship (13 May 2020).