Reinfections with SARS-CoV-2 have already been documented in humans, although its real incidence is currently unknown. Besides having great impact on public health, this phenomenon raises the question if immunity generated by a single infection is sufficient to provide sterilizing/protective immunity to a subsequent SARS-CoV-2 re-exposure. The Golden Syrian hamster is a manageable animal model to explore immunological mechanisms able to counteract COVID-19, as it recapitulates pathological aspects of mild to moderately affected patients. Here, we report that SARS-CoV-2-inoculated hamsters resolve infection in the upper and lower respiratory tracts within seven days upon inoculation with the Cat01 (G614) SARS-CoV-2 isolate. Three weeks after primary challenge, and despite high titers of neutralizing antibodies, half of the animals were susceptible to reinfection by both identical (Cat01, G614) and variant (WA/1, D614) SARS-CoV-2 isolates. However, upon re-inoculation, only nasal tissues were transiently infected with much lower viral replication than those observed after the first inoculation. These data indicate that a primary SARS-CoV-2 infection is not sufficient to elicit a sterilizing immunity in hamster models but protects against lung disease.

中文翻译：

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防止仓鼠中D614-或G614-SARS-CoV-2分离株再感染

尽管目前尚不知道SARS-CoV-2的再感染已在人类中发生。除了对公共卫生产生重大影响外，这种现象还引发了一个问题，即由一次感染产生的免疫是否足以为随后的SARS-CoV-2再次暴露提供灭菌/保护性免疫。金叙利亚仓鼠是一种易于管理的动物模型，旨在探索能够抵消COVID-19的免疫机制，因为它概括了轻度至中度感染患者的病理状况。在这里，我们报告说，接种Cat01（G614）SARS-CoV-2分离株后，接种SARS-CoV-2的仓鼠可在7天内解决上呼吸道和下呼吸道的感染。初次攻击后三周，尽管中和抗体滴度很高，一半的动物都受到相同（Cat01，G614）和变体（WA / 1，D614）SARS-CoV-2分离株的再感染。但是，重新接种后，仅鼻部组织被瞬时感染，其病毒复制率比第一次接种后观察到的低得多。这些数据表明，原发性SARS-CoV-2感染不足以在仓鼠模型中引发杀菌免疫，但可以预防肺部疾病。