Center for Health Emergencies, Bruno Kessler Foundation, Trento, Italy.
University of Udine, Udine, Italy.
BMC Med. 2021 Apr 9;19(1):89. doi: 10.1186/s12916-021-01967-w.
COVID-19 spread may have a dramatic impact in countries with vulnerable economies and limited availability of, and access to, healthcare resources and infrastructures. However, in sub-Saharan Africa, a low prevalence and mortality have been observed so far.
We collected data on individuals' social contacts in the South West Shewa Zone (SWSZ) of Ethiopia across geographical contexts characterized by heterogeneous population density, work and travel opportunities, and access to primary care. We assessed how socio-demographic factors and observed mixing patterns can influence the COVID-19 disease burden, by simulating SARS-CoV-2 transmission in remote settlements, rural villages, and urban neighborhoods, under school closure mandate.
From national surveillance data, we estimated a net reproduction number of 1.62 (95% CI 1.55-1.70). We found that, at the end of an epidemic mitigated by school closure alone, 10-15% of the population residing in the SWSZ would have been symptomatic and 0.3-0.4% of the population would require mechanical ventilation and/or possibly result in a fatal outcome. Higher infection attack rates are expected in more urbanized areas, but the highest incidence of critical disease is expected in remote subsistence farming settlements. School closure contributed to reduce the reproduction number by 49% and the attack rate of infections by 28-34%.
Our results suggest that the relatively low burden of COVID-19 in Ethiopia observed so far may depend on social mixing patterns, underlying demography, and the enacted school closures. Our findings highlight that socio-demographic factors can also determine marked heterogeneities across different geographical contexts within the same region, and they contribute to understand why sub-Saharan Africa is experiencing a relatively lower attack rate of severe cases compared to high-income countries.
在经济脆弱、医疗资源和基础设施有限的国家，COVID-19 的传播可能会产生巨大影响。然而，到目前为止，在撒哈拉以南非洲，观察到的发病率和死亡率都很低。
我们在埃塞俄比亚西南Shewa 区（SWSZ）收集了个人社会接触的数据，这些数据跨越了具有不同人口密度、工作和旅行机会以及获得初级保健的地理环境。我们评估了社会人口因素和观察到的混合模式如何影响 COVID-19 的疾病负担，通过模拟 SARS-CoV-2 在偏远定居点、农村村庄和城市社区中的传播，在学校关闭的情况下。
从国家监测数据中，我们估计了净繁殖数为 1.62（95%CI 1.55-1.70）。我们发现，在仅通过学校关闭来减轻疫情的情况下，SWSZ 居住的 10-15%的人口将出现症状，0.3-0.4%的人口将需要机械通气和/或可能导致致命后果。人口密度较高的地区预计会有更高的感染攻击率，但偏远的自给农业定居点预计会出现最严重的疾病发病率。学校关闭有助于将繁殖数减少 49%，感染攻击率降低 28-34%。
我们的研究结果表明，埃塞俄比亚迄今为止观察到的 COVID-19 相对较低的负担可能取决于社会混合模式、潜在的人口统计学和实施的学校关闭。我们的研究结果强调，社会人口因素也可以决定同一地区不同地理环境之间的显著异质性，并有助于理解为什么撒哈拉以南非洲的重症病例攻击率相对较低，而不是高收入国家。
