Prevalence of SARS-CoV-2 in six districts in Zambia in July, 2020: a cross-sectional cluster sample survey.
Prevalence of SARS-CoV-2 in six districts in Zambia in July, 2020: a cross-sectional cluster sample survey.
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DOI：
10.1016/s2214-109x(21)00053-x
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
Malama K
中科院分区：
文献类型：
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作者：
Mulenga LB;Hines JZ;Fwoloshi S;Chirwa L;Siwingwa M;Yingst S;Wolkon A;Barradas DT;Favaloro J;Zulu JE;Banda D;Nikoi KI;Kampamba D;Banda N;Chilopa B;Hanunka B;Stevens TL Jr;Shibemba A;Mwale C;Sivile S;Zyambo KD;Makupe A;Kapina M;Mweemba A;Sinyange N;Kapata N;Zulu PM;Chanda D;Mupeta F;Chilufya C;Mukonka V;Agolory S;Malama K
2020年3月至12月期间，赞比亚报告了2万多例实验室确诊的SARS-CoV-2感染病例。然而，SARS-CoV-2感染人数可能高于确诊病例数，因为许多感染者症状轻微或没有症状，而且赞比亚的检测能力和监测系统存在局限性。我们的目的是估计SARS-CoV-2在赞比亚六个地区的流行在2020年7月，使用基于人口的家庭调查。在2020年7月4日至7月27日期间，我们对赞比亚六个地区的家庭进行了横断面聚类抽样调查。在每个地区内，16个标准化的查点区域被随机选择作为主要抽样单位，使用与大小成比例的概率。以简单随机抽样方法，从每个标准化点算地区选出20个住户。所有被选中的家庭成员都有资格参加。参与者完成了一份问卷，并使用实时PCR（rtPCR）和ELISA检测SARS-CoV-2抗体检测SARS-CoV-2感染。患病率估计，调整调查设计，分别计算每一个诊断测试，并结合。我们将流行率估计值应用于每个地区的人口普查人口预测，以得出SARS-CoV-2感染的估计数量。共有来自1866个家庭的4258人参加了这项研究。参与者的中位年龄为18.2岁（IQR 7.7 - 31.4），50.6%的参与者为女性。综合测量的SARS-CoV-2患病率为10.6%（95%CI 7.3 - 13.9）。rtPCR阳性率为7.6%（4.7 ~ 10.6），ELISA阳性率为2.1%（1.1 ~ 3.1）。据估计，2020年3月至7月期间，这六个地区发生了454708例SARS-CoV-2感染（95%CI 312705 - 596713），而赞比亚国家公共卫生研究所的官方统计数据报告了4917例实验室确诊病例。估计的SARS-CoV-2感染人数远远高于赞比亚六个地区报告的病例数。高rtPCR阳性SARS-CoV-2流行率与研究期间观察到的社区传播一致。ELISA阳性SARS-CoV-2流行率较低可能与2020年3月报告初始病例后采取的缓解措施有关。赞比亚应监测SARS-CoV-2的流行模式，并促进可减少传播的措施。
Between March and December, 2020, more than 20 000 laboratory-confirmed cases of SARS-CoV-2 infection were reported in Zambia. However, the number of SARS-CoV-2 infections is likely to be higher than the confirmed case counts because many infected people have mild or no symptoms, and limitations exist with regard to testing capacity and surveillance systems in Zambia. We aimed to estimate SARS-CoV-2 prevalence in six districts of Zambia in July, 2020, using a population-based household survey. Between July 4 and July 27, 2020, we did a cross-sectional cluster-sample survey of households in six districts of Zambia. Within each district, 16 standardised enumeration areas were randomly selected as primary sampling units using probability proportional to size. 20 households from each standardised enumeration area were selected using simple random sampling. All members of selected households were eligible to participate. Consenting participants completed a questionnaire and were tested for SARS-CoV-2 infection using real-time PCR (rtPCR) and anti-SARS-CoV-2 antibodies using ELISA. Prevalence estimates, adjusted for the survey design, were calculated for each diagnostic test separately, and combined. We applied the prevalence estimates to census population projections for each district to derive the estimated number of SARS-CoV-2 infections. Overall, 4258 people from 1866 households participated in the study. The median age of participants was 18·2 years (IQR 7·7–31·4) and 50·6% of participants were female. SARS-CoV-2 prevalence for the combined measure was 10·6% (95% CI 7·3–13·9). The rtPCR-positive prevalence was 7·6% (4·7–10·6) and ELISA-positive prevalence was 2·1% (1·1–3·1). An estimated 454 708 SARS-CoV-2 infections (95% CI 312 705–596 713) occurred in the six districts between March and July, 2020, compared with 4917 laboratory-confirmed cases reported in official statistics from the Zambia National Public Health Institute. The estimated number of SARS-CoV-2 infections was much higher than the number of reported cases in six districts in Zambia. The high rtPCR-positive SARS-CoV-2 prevalence was consistent with observed community transmission during the study period. The low ELISA-positive SARS-CoV-2 prevalence might be associated with mitigation measures instituted after initial cases were reported in March, 2020. Zambia should monitor patterns of SARS-CoV-2 prevalence and promote measures that can reduce transmission.