The outbreak of SARS-CoV-2-associated pneumonia, a disease called COVID-19, has caused a pandemic worldwide. To investigate the immune responses after infection of SARS-CoV-2 in non-critical patients may help to better understand the disease progression. We collected 334 confirmed COVID-19 cases including 212 still in hospital with nucleic acid test positive on halfway for SARS-CoV-2 and 122 discharged from hospital, compared specific antibodies, immune cells, and cytokine changes between the hospitalized and discharged patients. The hospitalized patients had a longer illness time compared with discharged patients. Analysis of viral loads explained long-term or persistent infection of SARS-CoV-2, which existed with the median time of 18.5 days of the positive nucleic acid test. Serum analysis showed that the specific anti-N IgG antibody was positive in all detected patients after infection of two weeks. Neutrophils, Monocytes, NK cells, and CD4⁺ T cells significantly increased, while total lymphocytes and CD8⁺ T cells decreased from non-critical hospitalized patients after longer-term infection. Further analysis of the cytokines showed that IL-6, TNF-α, IFN-γ, IL-2, IL-4, and IL-10 from the hospitalized patients were significantly higher, indicating a potential of the increased CD4⁺ T cell differentiation.

SARS-CoV-2相关性肺炎的暴发（一种称为COVID-19的疾病）已引起全球大流行。调查非严重患者SARS-CoV-2感染后的免疫反应可能有助于更好地了解疾病进展。我们收集了334例确诊的COVID-19病例，包括212例​​仍在医院中，且SARS-CoV-2核酸检测中途呈阳性，而122例出院，比较了住院和出院患者之间的特异性抗体，免疫细胞和细胞因子变化。与出院患者相比，住院患者的疾病时间更长。病毒载量分析解释了SARS-CoV-2的长期或持续感染，该病毒以阳性核酸测试的中位时间为18.5天存在。血清分析表明，感染两周后，所有检测到的患者中特异性抗N IgG抗体均为阳性。中性粒细胞，单核细胞，NK细胞和CD4长期感染后，非危重住院患者的⁺ T细胞显着增加，而总淋巴细胞和CD8 ⁺ T细胞减少。细胞因子的进一步分析显示，住院患者的IL-6，TNF-α，IFN-γ，IL-2，IL-4和IL-10明显更高，表明CD4 ⁺ T细胞分化可能增加。