Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study.
Assessment of protection against reinfection with SARS-CoV-2 among 4 million PCR-tested individuals in Denmark in 2020: a population-level observational study.
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DOI：
10.1016/s0140-6736(21)00575-4
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发表时间：
2021-03-27
期刊：
影响因子：
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通讯作者：
Ethelberg S
中科院分区：
文献类型：
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作者：
Hansen CH;Michlmayr D;Gubbels SM;Mølbak K;Ethelberg S
感染SARS-CoV-2对随后的再感染提供保护的程度尚未得到很好的描述。2020年，作为丹麦广泛的免费pcr检测战略的一部分，约有400万人（占人口的69%）接受了1060万次检测。利用这些2020年以来的国家pcr检测数据，我们估计了对SARS-CoV-2重复感染的保护。在这项人群水平的观察性研究中，我们从丹麦微生物数据库中收集了2020年在丹麦接受检测的患者的个人水平数据，并通过比较第一次激增（2020年3月至5月）期间PCR检测阳性和阴性个体之间的感染率，分析了2020年9月1日至12月31日第二次COVID-19流行高峰期间的感染率。在主要分析中，我们排除了在两次激增之间首次检测呈阳性的人和在第二次激增之前死亡的人。我们进行了另一项队列分析，其中我们比较了至少3个月前确诊感染和未确诊感染的患者全年的感染率，而不考虑日期。在替代队列分析中，我们还调查了年龄、性别和感染时间是否存在差异。我们计算了经潜在混杂因素调整后的比率（RR），并估计防止重复感染的保护为1 - RR。在第一次激增期间（即2020年6月之前），检测了533 381人，其中11 727人（2.20%）为PCR阳性，525 339人有资格在第二次激增中进行随访，其中11 068人（2.11%）在第一次激增期间检测呈阳性。在第一次流行高峰中符合条件的pcr阳性个体中，有72人（0.65% [95% CI 0.51 - 0.82]）在第二次高峰期间再次检测为阳性，而在第一次高峰期间检测为阴性的514271人中有16819人（3.27%[3.22 - 3.32]）（调整后RR为0.195 [95% CI 0.155 - 0.246]）。对重复感染的保护率为80·5% （95% CI为74.5 - 84.5）。替代队列分析给出了类似的估计（调整后的RR为0.212[0.179 - 0.251]，估计保护率为78.8%[74.9 - 82.1]）。在替代队列分析中，在65岁及以上的患者中，观察到对重复感染的保护为47.1% （95% CI 24.7 - 62.8）。我们发现性别对重复感染的估计保护没有差异（男性78.4%[72.1 - 83.2]对女性79.1%[73.9 - 83.3]），也没有证据表明随着时间的推移保护会减弱（3 - 6个月随访79.3%[74.1 - 83.3]对≥7个月随访77.7%[70.9 - 82.9]）。我们的研究结果可以为哪些群体应该接种疫苗的决定提供信息，并倡导对以前感染过的个体接种疫苗，因为不能依赖自然保护，尤其是老年人。没有。
The degree to which infection with SARS-CoV-2 confers protection towards subsequent reinfection is not well described. In 2020, as part of Denmark's extensive, free-of-charge PCR-testing strategy, approximately 4 million individuals (69% of the population) underwent 10·6 million tests. Using these national PCR-test data from 2020, we estimated protection towards repeat infection with SARS-CoV-2. In this population-level observational study, we collected individual-level data on patients who had been tested in Denmark in 2020 from the Danish Microbiology Database and analysed infection rates during the second surge of the COVID-19 epidemic, from Sept 1 to Dec 31, 2020, by comparison of infection rates between individuals with positive and negative PCR tests during the first surge (March to May, 2020). For the main analysis, we excluded people who tested positive for the first time between the two surges and those who died before the second surge. We did an alternative cohort analysis, in which we compared infection rates throughout the year between those with and without a previous confirmed infection at least 3 months earlier, irrespective of date. We also investigated whether differences were found by age group, sex, and time since infection in the alternative cohort analysis. We calculated rate ratios (RRs) adjusted for potential confounders and estimated protection against repeat infection as 1 – RR. During the first surge (ie, before June, 2020), 533 381 people were tested, of whom 11 727 (2·20%) were PCR positive, and 525 339 were eligible for follow-up in the second surge, of whom 11 068 (2·11%) had tested positive during the first surge. Among eligible PCR-positive individuals from the first surge of the epidemic, 72 (0·65% [95% CI 0·51–0·82]) tested positive again during the second surge compared with 16 819 (3·27% [3·22–3·32]) of 514 271 who tested negative during the first surge (adjusted RR 0·195 [95% CI 0·155–0·246]). Protection against repeat infection was 80·5% (95% CI 75·4–84·5). The alternative cohort analysis gave similar estimates (adjusted RR 0·212 [0·179–0·251], estimated protection 78·8% [74·9–82·1]). In the alternative cohort analysis, among those aged 65 years and older, observed protection against repeat infection was 47·1% (95% CI 24·7–62·8). We found no difference in estimated protection against repeat infection by sex (male 78·4% [72·1–83·2] vs female 79·1% [73·9–83·3]) or evidence of waning protection over time (3–6 months of follow-up 79·3% [74·4–83·3] vs ≥7 months of follow-up 77·7% [70·9–82·9]). Our findings could inform decisions on which groups should be vaccinated and advocate for vaccination of previously infected individuals because natural protection, especially among older people, cannot be relied on. None.