Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, USA.
Department of Infectious Disease, Cleveland Clinic, Cleveland, Ohio, USAand.
Clin Infect Dis. 2022 Aug 24;75(1):e185-e190. doi: 10.1093/cid/ciab999.
Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to be highly protective against reinfection and symptomatic disease. However, effectiveness against the Delta variant and duration of natural immunity remain unknown.
This retrospective cohort study included 325 157 patients tested for SARS-CoV-2 via polymerase chain reaction (PCR) from 9 March 2020 to 31 December 2020 (Delta variant analysis) and 152 656 patients tested from 9 March 2020 to 30 August 2020 (long-term effectiveness analysis) with subsequent testing through 9 September 2021. The primary outcome was reinfection, defined as a positive PCR test >90 days after the initial positive test.
Among 325 157 patients tested before 31 December 2020, 50 327 (15.5%) tested positive. After 1 July 2021 (Delta dominant period), 40 (0.08%) initially positive and 1494 (0.5%) initially negative patients tested positive. Protection of prior infection against reinfection with Delta was 85.4% (95% confidence interval [CI], 80.0-89.3). For the long-term effectiveness analysis, among 152 656 patients tested before 30 August 2020, 11 186 (7.3%) tested positive. After at least 90 days, 81 (0.7%) initially positive and 7167 (5.1%) initially negative patients tested positive. Overall protection of previous infection was 85.7% (95% CI, 82.2-88.5) and lasted up to 13 months. Patients aged >65 years had slightly lower protection.
SARS-CoV-2 infection is highly protective against reinfection with Delta. Immunity from prior infection lasts at least 13 months. Countries facing vaccine shortages should consider delaying vaccinations for previously infected patients to increase access.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）感染已被证明对再次感染和有症状疾病具有高度保护作用。然而，其对 Delta 变体的有效性和自然免疫的持续时间尚不清楚。
这项回顾性队列研究纳入了 2020 年 3 月 9 日至 2020 年 12 月 31 日期间通过聚合酶链反应（PCR）检测 SARS-CoV-2 的 325157 例患者（Delta 变体分析）和 2020 年 3 月 9 日至 2020 年 8 月 30 日期间检测的 152656 例患者（长期有效性分析），随后检测持续到 2021 年 9 月 9 日。主要结局是再次感染，定义为初次阳性检测后 90 天以上的 PCR 检测阳性。
在 2020 年 12 月 31 日前接受检测的 325157 例患者中，50327 例（15.5%）检测结果为阳性。2021 年 7 月 1 日（Delta 主导期）后，40 例（0.08%）初次阳性和 1494 例（0.5%）初次阴性患者检测结果为阳性。先前感染对 Delta 变体再感染的保护率为 85.4%（95%置信区间[CI]，80.0-89.3）。在 2020 年 8 月 30 日前接受检测的 152656 例患者中，有 11186 例（7.3%）检测结果为阳性。至少 90 天后，81 例（0.7%）初次阳性和 7167 例（5.1%）初次阴性患者检测结果为阳性。先前感染的总体保护率为 85.7%（95%CI，82.2-88.5），持续时间长达 13 个月。年龄>65 岁的患者保护作用略低。
SARS-CoV-2 感染对 Delta 变体再感染具有高度保护作用。先前感染产生的免疫力至少持续 13 个月。面临疫苗短缺的国家应考虑推迟为已感染患者接种疫苗，以增加疫苗接种机会。
