Different clinical features in Malawian outpatients presenting with COVID-19 prior to and during Omicron variant dominance: A prospective observational study.
Different clinical features in Malawian outpatients presenting with COVID-19 prior to and during Omicron variant dominance: A prospective observational study.
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DOI：
10.1371/journal.pgph.0001575
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发表时间：
2023
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SARS-CoV-2 OMICRON变种导致了大量病例，但与前OMICRON变种相比，严重疾病和死亡的发生率相对较低。因此，我们评估了撒哈拉以南非洲人群中奥美康和奥美康前感染之间的症状患病率的差异。我们收集了2020年11月至2022年3月在马拉维布兰太尔的两家初级医疗机构就诊的门诊患者的数据。符合条件的受试者年龄为1个月大，有新冠肺炎征象，以及那些不怀疑新冠肺炎的人，我们从他们那里采集鼻咽拭子进行SARS-CoV-2聚合酶链式反应检测，并对阳性样本进行测序以确定感染变异株。此外，我们计算了在检测SARS-CoV-2聚合酶链式反应阳性的个体中，在Omicron变异占主导地位的时期之前和期间出现给定症状的风险。在5176名参与者中，6.4%的人年龄在5岁以下，77%的人年龄在18岁到50岁之间。SARS-CoV-2感染流行在2021年1月(Beta)、2021年7月(Delta)和2021年12月(Omicron)达到顶峰。我们发现咳嗽(风险比(RR)为1.50；95%可信区间(CI)为1.00~2.30)、乏力(RR为2.27；95%CI为1.29~3.86)和头痛(RR为1.64；95%CI为1.15~2.34)与SARS-CoV-2感染的高危相关。相比之下，只有头痛(相对危险度1.41；95%可信区间，1.07至1.86)确实与奥美康占主导地位的时期感染SARS-CoV-2的高风险有关。总而言之，与奥美康感染相关的临床症状不同于以前的变种，更难根据当前的症状指南进行临床识别。我们的调查结果鼓励定期审查病例定义和检测政策，以确保病例查明。
The SARS-CoV-2 Omicron variant has resulted in a high number of cases, but a relatively low incidence of severe disease and deaths, compared to the pre-Omicron variants. Therefore, we assessed the differences in symptom prevalence between Omicron and pre-Omicron infections in a sub-Saharan African population. We collected data from outpatients presenting at two primary healthcare facilities in Blantyre, Malawi, from November 2020 to March 2022. Eligible participants were aged >1month old, with signs suggestive of COVID-19, and those not suspected of COVID-19, from whom we collected nasopharyngeal swabs for SARS-CoV-2 PCR testing, and sequenced positive samples to identify infecting-variants. In addition, we calculated the risk of presenting with a given symptom in individuals testing SARS-CoV-2 PCR positive before and during the Omicron variant-dominated period. Among 5176 participants, 6.4% were under 5, and 77% were aged 18 to 50 years. SARS-CoV-2 infection prevalence peaked in January 2021 (Beta), July 2021 (Delta), and December 2021 (Omicron). We found that cough (risk ratio (RR), 1.50; 95% confidence interval (CI), 1.00 to 2.30), fatigue (RR 2.27; 95% CI, 1.29 to 3.86) and headache (RR 1.64; 95% CI, 1.15 to 2.34) were associated with a high risk of SARS-CoV-2 infection during the pre-Omicron period. In comparison, only headache (RR 1.41; 95% CI, 1.07 to 1.86) did associate with a high risk of SARS-CoV-2 infection during the Omicron-dominated period. In conclusion, clinical symptoms associated with Omicron infection differed from prior variants and were harder to identify clinically with current symptom guidelines. Our findings encourage regular review of case definitions and testing policies to ensure case ascertainment.