[HTML][HTML] Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections

QX Long, XJ Tang, QL Shi, Q Li, HJ Deng, J Yuan… - Nature medicine, 2020 - nature.com
QX Long, XJ Tang, QL Shi, Q Li, HJ Deng, J Yuan, JL Hu, W Xu, Y Zhang, FJ Lv, K Su…
Nature medicine, 2020nature.com
The clinical features and immune responses of asymptomatic individuals infected with
severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been well
described. We studied 37 asymptomatic individuals in the Wanzhou District who were
diagnosed with RT–PCR-confirmed SARS-CoV-2 infections but without any relevant clinical
symptoms in the preceding 14 d and during hospitalization. Asymptomatic individuals were
admitted to the government-designated Wanzhou People's Hospital for centralized isolation …
Abstract
The clinical features and immune responses of asymptomatic individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been well described. We studied 37 asymptomatic individuals in the Wanzhou District who were diagnosed with RT–PCR-confirmed SARS-CoV-2 infections but without any relevant clinical symptoms in the preceding 14 d and during hospitalization. Asymptomatic individuals were admitted to the government-designated Wanzhou People’s Hospital for centralized isolation in accordance with policy 1. The median duration of viral shedding in the asymptomatic group was 19 d (interquartile range (IQR), 15–26 d). The asymptomatic group had a significantly longer duration of viral shedding than the symptomatic group (log-rank P= 0.028). The virus-specific IgG levels in the asymptomatic group (median S/CO, 3.4; IQR, 1.6–10.7) were significantly lower (P= 0.005) relative to the symptomatic group (median S/CO, 20.5; IQR, 5.8–38.2) in the acute phase. Of asymptomatic individuals, 93.3%(28/30) and 81.1%(30/37) had reduction in IgG and neutralizing antibody levels, respectively, during the early convalescent phase, as compared to 96.8%(30/31) and 62.2%(23/37) of symptomatic patients. Forty percent of asymptomatic individuals became seronegative and 12.9% of the symptomatic group became negative for IgG in the early convalescent phase. In addition, asymptomatic individuals exhibited lower levels of 18 pro-and anti-inflammatory cytokines. These data suggest that asymptomatic individuals had a weaker immune response to SARS-CoV-2 infection. The reduction in IgG and neutralizing antibody levels in the early convalescent phase might have implications for immunity strategy and serological surveys.
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