埃塞俄比亚非洲疾病控制和预防中心Stephanie J Salyer团队分析了非洲COVID-19大流行的第一波和第二波情况。2021年3月24日，该研究发表在《柳叶刀》上。
尽管第一波COVID-19疫情在非洲的传播速度比世界其他地区慢，但到2020年12月，第二波疫情似乎更具侵略性，出现了更多的病例。迄今为止，尚未全面审查非洲联盟（非盟）所有55个成员国的流行病情况。
为了评估报告的COVID-19流行病学数据，以便更好地了解非洲大流行的进展，2020年2月14日至12月31日，研究组进行了一项横断面分析，使用非盟成员国报告的COVID-19流行病学、检测和缓解策略数据，评估趋势，确定国家、区域层面的应对和缓解努力。研究组对感兴趣的变量进行了描述性分析，包括累积和每周发病率、病死率（CFR）、每例检测比率、增长率以及公共卫生和社会措施。
截至2020年12月31日，非洲国家报告了2 763 421例COVID-19病例和65 602例死亡，分别占全球报告的82 312 150例和798 994例死亡病例的3.4%和3.6%。55个国家中有9个国家的报告病例占82.6%以上（2 283 613）。18个国家报告CFR高于全球CFR（2.2%）。17个国家报告的每例检测比率低于建议的每例10至30次检测比率范围。在2020年7月非洲的第一波高峰时期，平均每日新增病例数为18 273例。
截至2020年12月31日，40个国家（73%）已经或正在经历第二波疫情，非洲大陆在第53周的流行病学调查中平均每天报告23790例新病例。截至2020年4月15日，50个成员国中有48个（96%）国家实施了5项及以上的公共卫生和社会措施，但截至2020年12月31日，这一数字已降至36个（72%），尽管前一个月的病例有所增加。
该研究分析表明，非洲大陆的第二波COVID-19疫情比第一次更严重，并强调了长期以来在区域和国家层面上检查多个流行病学变量的重要性。
附：英文原文
Title: The first and second waves of the COVID-19 pandemic in Africa: a cross-sectional study
Author: Stephanie J Salyer, Justin Maeda, Senga Sembuche, Yenew Kebede, Akhona Tshangela, Mohamed Moussif, Chikwe Ihekweazu, Natalie Mayet, Ebba Abate, Ahmed Ogwell Ouma, John Nkengasong
Issue&Volume: 2021-03-24
Abstract: Background
Although the first wave of the COVID-19 pandemic progressed more slowly in Africa than the rest of the world, by December, 2020, the second wave appeared to be much more aggressive with many more cases. To date, the pandemic situation in all 55 African Union (AU) Member States has not been comprehensively reviewed. We aimed to evaluate reported COVID-19 epidemiology data to better understand the pandemic's progression in Africa.
Methods
We did a cross-sectional analysis between Feb 14 and Dec 31, 2020, using COVID-19 epidemiological, testing, and mitigation strategy data reported by AU Member States to assess trends and identify the response and mitigation efforts at the country, regional, and continent levels. We did descriptive analyses on the variables of interest including cumulative and weekly incidence rates, case fatality ratios (CFRs), tests per case ratios, growth rates, and public health and social measures in place.
Findings
As of Dec 31, 2020, African countries had reported 2763421 COVID-19 cases and 65602 deaths, accounting for 3·4% of the 82312150 cases and 3·6% of the 1798994 deaths reported globally. Nine of the 55 countries accounted for more than 82·6% (2283613) of reported cases. 18 countries reported CFRs greater than the global CFR (2·2%). 17 countries reported test per case ratios less than the recommended ten to 30 tests per case ratio range. At the peak of the first wave in Africa in July, 2020, the mean daily number of new cases was 18273. As of Dec 31, 2020, 40 (73%) countries had experienced or were experiencing their second wave of cases with the continent reporting a mean of 23790 daily new cases for epidemiological week 53. 48 (96%) of 50 Member States had five or more stringent public health and social measures in place by April 15, 2020, but this number had decreased to 36 (72%) as of Dec 31, 2020, despite an increase in cases in the preceding month.
Interpretation
Our analysis showed that the African continent had a more severe second wave of the COVID-19 pandemic than the first, and highlights the importance of examining multiple epidemiological variables down to the regional and country levels over time. These country-specific and regional results informed the implementation of continent-wide initiatives and supported equitable distribution of supplies and technical assistance. Monitoring and analysis of these data over time are essential for continued situational awareness, especially as Member States attempt to balance controlling COVID-19 transmission with ensuring stable economies and livelihoods.
DOI: 10.1016/S0140-6736(21)00632-2
Source: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00632-2/fulltext
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