AUTHOR=Xu Hui , Xie Cheng-yuan , Li Pei-hong , Ji Zhong-liang , Sun Jiu-feng , Hu Bei , Li Xin , Fang Ming 

TITLE=Demographic, Virological Characteristics and Prognosis of Asymptomatic COVID-19 Patients in South China

JOURNAL=Frontiers in Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.830942

DOI=10.3389/fmed.2022.830942

ISSN=2296-858X

ABSTRACT=Background: Asymptomatic transmission is a major concern for SARS-CoV-2 community spread; however, little information is available ondemographic, virological characteristics and prognosis of asymptomatic cases. 
Methods: All COVID-19 patients hospitalized in Guangdong Province from September 1, 2020 to February 28, 2021, were included and were divided into asymptomatic and symptomatic group. The origin of all patients, clinical laboratory test results, the genotype of virus and the time of SARS-CoV-2 RNA turning negative or hospitalization were confirmed. 
Results:Total 233 patients from 57 different countries or regions were included, with 83 (35.6%) asymptomatic and 150 (64.4%) symptomatic patients. Asymptomatic cases were younger (P=0.019), lower rate in comorbidities (P=0.021) such as hypertension (P=0.083), chronic lung disease (P=0.056) and chronic liver disease (P=0.045), lower PCT (P=0.021), DDI (P<0.001) and ALT (P=0.029), but higher WBC count (P=0.002) and lymphocyte (P=0.011) than symptomatic patients. As for SARS-CoV-2 subtypes, patients infected with B.1.1 (53.8%), B.1.351 (81.8%) and B.1.524 (60%) are mainly asymptomatic, while infected with B, B.1, B.1.1.63, B.1.1.7, B.1.36, B.1.36.1, B.1.36.16, B.1.5 and B.6 were inclined to be symptomatic. Patients infected with variant B.1.351and B.1.524 spent longer time in SARS-CoV-2 RNA turn negative (26 days, P=0.085; 41 days, P=0.007) and hospitalization (28 days, P=0.085; 43 days, P=0.004). 
Conclusions: The asymptomatic cases are prone to develop in patients with younger age, less comorbidities and infected with B.1.1 and B.1.524 variants. More attention should be paid for lineage B.1.524 because it can significantly prolong the SARS-CoV-2 RNA negative conversion time and hospitalization in infected cases.