Evaluation of the E gene RT-PCR Ct Values in Clinical Samples from Symptomatic and Asymptomatic COVID-19 Patients

Abstract

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread globally and is a major public health issue. Procedures that have been established to decrease the spread of the virus depend on the careful and precise detection of infected individuals using quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). There have been many ambiguous concerns among the public regarding the severity of infection and its connection with the Cycle threshold (Ct) value and there was forceful need to inform the values to the public especially those with symptoms. The main objective of this study was to determine the association between the E (Envelop) gene Ct values of the symptomatic and asymptomatic COVID 19 patients. The study was conducted at the Virus Research and Diagnostic Laboratory (VRDL), Jagdalpur, Chhattisgarh. Between March 2020 and June 2020, samples were collected from the Bastar region as per the Indian Council of Medical Research (ICMR) guidelines. A total of 29228 clinical samples were tested by qRT-PCR targeting the E and RdRp (RNA-dependant RNA polymerase) genes as well as the ORF (open reading frame) gene that encode polyproteins of SARS-CoV-2. Of the 29228 samples tested, 75 were tested positive and 29153 were tested negative. In addition, the Ct values varied between the symptomatic and asymptomatic patients. It was observed that, the Ct values ranged from 15 to 32 in the asymptomatic patients and between 13 to 34 in the symptomatic patients. E gene Ct value analysis showed no significant difference between the asymptomatic and symptomatic COVID-19 patients. Thus, we observed that there was no association between the Ct values of symptomatic and asymptomatic patients of COVID-19.