Abstract:
The estimates of contiguousness parameters of an epidemic have been used
for health-related policy and control measures such as non-pharmaceutical control
interventions (NPIs). The estimates have varied by demographics, epidemic phase, and
geographical region. Our aim was to estimate four contagiousness parameters: basic
reproduction number (R0), contact rate, removal rate, and infectious period of coronavirus
disease 2019 (COVID-19) among eight African countries, namely Angola, Botswana,
Egypt, Ethiopia, Malawi, Nigeria, South Africa, and Tunisia using Susceptible, Infectious,
or Recovered (SIR) epidemic models for the period 1 January 2020 to 31 December
2021. For reference, we also estimated these parameters for three of COVID-19’s most
severely affected countries: Brazil, India, and the USA. The basic reproduction number,
contact and remove rates, and infectious period ranged from 1.11 to 1.59, 0.53 to 1.0,
0.39 to 0.81; and 1.23 to 2.59 for the eight African countries. For the USA, Brazil, and
India these were 1.94, 0.66, 0.34, and 2.94; 1.62, 0.62, 0.38, and 2.62, and 1.55,
0.61, 0.39, and 2.55, respectively. The average COVID-19 related case fatality rate for 8
African countries in this study was estimated to be 2.86%. Contact and removal rates
among an affected African population were positively and significantly associated with
COVID-19 related deaths (p-value < 0.003). The larger than one estimates of the basic
reproductive number in the studies of African countries indicate that COVID-19 was still
being transmitted exponentially by the 31 December 2021, though at different rates. The
spread was even higher for the three countries with substantial COVID-19 outbreaks. The
lower removal rates in the USA, Brazil, and India could be indicative of lower death rates
(a proxy for good health systems). Our findings of variation in the estimate of COVID-19 contagiousness parameters imply that countries in the region may implement differential
COVID-19 containment measures.
