Unusual mortality rate differences and symptoms have been experienced by COVID-19 patients, and the postinfection symptoms called Long COVID-19 have also been widely experienced. A substantial percentage of COVID-19-infected individuals in specific health categories have been virtually asymptomatic, several other individuals in the same health categories have exhibited several unusual symptoms, and yet other individuals in the same health categories have fatal outcomes. It is now hypothesized that these differences in mortality rates and symptoms could be caused by a SARS-CoV-2 virus infection acting together with one or more latent pathogen infections in certain patients, through mutually beneficial induced immune cell dysfunctions, including T-cell exhaustion. A latent pathogen infection likely to be involved is the protozoan parasite Toxoplasma gondii, which infects approximately one third of the global human population. Furthermore, certain infections and cancers that cause T-cell exhaustion can also explain the more severe outcomes of other COVID-19 patients having several disease and cancer comorbidities.

中文翻译：

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T 细胞耗竭在长 COVID-19 中的作用和几类 COVID-19 患者的严重后果

COVID-19 患者经历了不寻常的死亡率差异和症状，并且被称为 Long COVID-19 的感染后症状也被广泛经历。在特定健康类别中，相当大比例的 COVID-19 感染者几乎没有症状，同一健康类别中的其他几个人表现出几种不寻常的症状，而同一健康类别中的其他人却有致命的后果。现在假设这些死亡率和症状的差异可能是由于 SARS-CoV-2 病毒感染与某些患者的一种或多种潜在病原体感染共同作用，通过互利诱导的免疫细胞功能障碍（包括 T 细胞衰竭）引起的. 可能涉及的潜在病原体感染是原生动物寄生虫弓形虫感染了全球约三分之一的人口。此外，某些导致 T 细胞衰竭的感染和癌症也可以解释其他患有多种疾病和癌症合并症的 COVID-19 患者的更严重后果。