Laboratório de Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane, Fiocruz, Manaus, Brazil.
Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Rio de Janeiro, Brazil.
Sci Rep. 2023 May 5;13(1):7306. doi: 10.1038/s41598-023-33443-1.
The rapid spread of the SARS-CoV-2 Variant of Concern (VOC) Gamma in Amazonas during early 2021 fueled a second large COVID-19 epidemic wave and raised concern about the potential role of reinfections. Very few cases of reinfection associated with the VOC Gamma have been reported to date, and their potential impact on clinical, immunological, and virological parameters remains largely unexplored. Here we describe 25 cases of SARS-CoV-2 reinfection in Brazil. SARS-CoV-2 genomic analysis confirmed that individuals were primo-infected with distinct viral lineages between March and December 2020 (B.1.1, B.1.1.28, B.1.1.33, B.1.195, and P.2) and reinfected with the VOC Gamma between 3 to 12 months after primo-infection. We found a similar mean cycle threshold (Ct) value and limited intra-host viral diversity in both primo-infection and reinfection samples. Sera of 14 patients tested 10-75 days after reinfection displayed detectable neutralizing antibodies (NAb) titers against SARS-CoV-2 variants that circulated before (B.1.*), during (Gamma), and after (Delta and Omicron) the second epidemic wave in Brazil. All individuals had milder or no symptoms after reinfection, and none required hospitalization. These findings demonstrate that individuals reinfected with the VOC Gamma may display relatively high RNA viral loads at the upper respiratory tract after reinfection, thus contributing to onward viral transmissions. Despite this, our study points to a low overall risk of severe Gamma reinfections, supporting that the abrupt increase in hospital admissions and deaths observed in Amazonas and other Brazilian states during the Gamma wave was mostly driven by primary infections. Our findings also indicate that most individuals analyzed developed a high anti-SARS-CoV-2 NAb response after reinfection that may provide some protection against reinfection or disease by different SARS-CoV-2 variants.
关注的 SARS-CoV-2 变体（VOC）Gamma 在 2021 年初在亚马逊州的迅速传播引发了第二波大的 COVID-19 疫情，并引发了对再感染潜在作用的担忧。迄今为止，与 VOC Gamma 相关的再感染病例非常少，其对临床、免疫和病毒学参数的潜在影响在很大程度上仍未得到探索。在这里，我们描述了巴西 25 例 SARS-CoV-2 再感染病例。SARS-CoV-2 基因组分析证实，这些个体在 2020 年 3 月至 12 月期间首次感染了不同的病毒谱系（B.1.1、B.1.1.28、B.1.1.33、B.1.195 和 P.2），并在首次感染后 3 至 12 个月内感染了 VOC Gamma。我们发现，在初次感染和再感染样本中，平均循环阈值（Ct）值相似，病毒内部多样性有限。在再感染后 10-75 天检测的 14 名患者的血清中，针对在巴西第二次疫情期间（Gamma）及之前（B.1.*）和之后（Delta 和 Omicron）流行的 SARS-CoV-2 变体，均检测到可检测的中和抗体（NAb）滴度。所有个体在再感染后均出现较轻或无症状，且无需住院治疗。这些发现表明，再感染 VOC Gamma 的个体在再感染后上呼吸道的 RNA 病毒载量可能相对较高，从而导致病毒继续传播。尽管如此，我们的研究表明，Gamma 再感染的总体风险较低，支持在 Gamma 波期间亚马逊州和巴西其他州观察到的住院人数和死亡人数的急剧增加主要是由初次感染驱动的。我们的研究结果还表明，大多数接受分析的个体在再感染后产生了高抗 SARS-CoV-2 NAb 反应，这可能为不同的 SARS-CoV-2 变体的再感染或疾病提供一定的保护。
