Population Immunity and Covid-19 Severity with Omicron Variant in South Africa.
Population Immunity and Covid-19 Severity with Omicron Variant in South Africa.
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DOI：
10.1056/nejmoa2119658
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发表时间：
2022-04-07
期刊：
影响因子：
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通讯作者：
Mutevedzi PC
中科院分区：
文献类型：
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作者：
Madhi SA;Kwatra G;Myers JE;Jassat W;Dhar N;Mukendi CK;Nana AJ;Blumberg L;Welch R;Ngorima-Mabhena N;Mutevedzi PC
我们于2021年10月22日至12月9日在南非豪登省进行了一项血清流行病学调查，以确定SARS-CoV-2免疫球蛋白G（IgG）血清阳性率，主要是在2019年第四波冠状病毒病（Covid-19）之前，其中B.1.1.529（Omicron）变体占主导地位。我们评估了豪登截至2022年1月12日的病例率和严重疾病率的流行病学趋势。我们联系了2020年11月至2021年1月进行的先前血清流行病学调查的住户，以及使用相同抽样框架的额外10%住户。在Luminex平台上使用定量测定法检测干血斑样品的抗加标和抗核衣壳蛋白IgG。每日病例、住院和报告的死亡数据，以及每周额外死亡，随时间作图。样本来自7010人，其中1319人（18.8%）接种了新冠疫苗。总体血清阳性率范围从<12岁儿童的56.2%（95%置信区间[CI]，52.6至59.7）到>50岁个体的79.7%（95% CI，77.6至81.5）。接种疫苗（93.1%）与未接种疫苗（68.4%）的个体相比，血清阳性的可能性更大。流行病学数据显示，SARS-CoV-2感染率上升，随后下降速度比前几波更快。感染率与新冠肺炎住院人数、记录的死亡人数以及相对于前三波的超额死亡人数脱钩。在O型病毒占主导地位之前，在豪登省观察到广泛的潜在SARS-CoV-2血清阳性。流行病学数据显示，在奥密克隆循环期间，住院率和死亡率与感染率脱钩。
We conducted a seroepidemiological survey from October 22 to December 9, 2021, in Gauteng Province, South Africa, to determine SARS-CoV-2 immunoglobulin G (IgG) seroprevalence primarily before the fourth wave of coronavirus disease 2019 (Covid-19), in which the B.1.1.529 (Omicron) variant was dominant. We evaluated epidemiological trends in case rates and rates of severe disease through to January 12, 2022, in Gauteng. We contacted households from a previous seroepidemiological survey conducted from November 2020 to January 2021, plus an additional 10% of households using the same sampling framework. Dry blood spot samples were tested for anti-spike and anti-nucleocapsid protein IgG using quantitative assays on the Luminex platform. Daily case, hospital admission, and reported death data, and weekly excess deaths, were plotted over time. Samples were obtained from 7010 individuals, of whom 1319 (18.8%) had received a Covid-19 vaccine. Overall seroprevalence ranged from 56.2% (95% confidence interval [CI], 52.6 to 59.7) in children aged <12 years to 79.7% (95% CI, 77.6 to 81.5) in individuals aged >50 years. Seropositivity was more likely in vaccinated (93.1%) vs unvaccinated (68.4%) individuals. Epidemiological data showed SARS-CoV-2 infection rates increased and subsequently declined more rapidly than in previous waves. Infection rates were decoupled from Covid-19 hospitalizations, recorded deaths, and excess deaths relative to the previous three waves. Widespread underlying SARS-CoV-2 seropositivity was observed in Gauteng Province before the Omicron-dominant wave. Epidemiological data showed a decoupling of hospitalization and death rates from infection rate during Omicron circulation.