key: cord-0702533-y87wy1rz authors: Anantharaj, Anbalagan; Gujjar, Sunil; Verma, Nikhil; Khan, Naseem Ahmed; Shaman, Heena; Sharanabasava, Patil; Das, Asim; Pandey, Rajesh; Pandey, Anil Kumar; Medigeshi, Guruprasad R. title: Resolution of viral load in mild COVID-19 patients is associated with both innate and adaptive immune responses date: 2021-12-21 journal: J Clin Virol DOI: 10.1016/j.jcv.2021.105060 sha: c0afa50a015b2649fafd5e2f5e148d9e17b07084 doc_id: 702533 cord_uid: y87wy1rz Over 90% of the COVID-19 patients manifest mild/moderate symptoms or are asymptomatic. Although comorbidities and dysregulation of immune response have been implicated in severe COVID-19, the host factors that associate with asymptomatic or mild infections have not been characterized. We have collected serial samples from 23 hospitalized COVID-19 patients with mild symptoms and measured the kinetics of SARS-CoV-2 viral load in respiratory samples and markers of inflammation in serum samples. We monitored seroconversion during the acute phase of illness and quantitated the amount of total IgG against the receptor-binding domain of SARS-CoV-2 and estimated the virus neutralization potential of these antibodies. Viral load decreased by day 8 in all the patients but the detection of viral RNA in saliva samples did not correlate well with viral RNA detection in nasopharyngeal/oropharyngeal swab samples. 25% of the virus-positive patients had no detectable neutralizing antibodies in the serum and in other cases, the efficiency of antibodies to neutralize SARS-CoV-2 B1.1.7 strain was lower as compared to the circulating virus isolate. Decrease in viral load coincided with increase in neutralizing antibodies and interferon levels in serum. Most patients showed no increase in inflammatory cytokines such as IL-1β or IL-6, however, elevated levels of IL-7 and other inflammatory mediators such as TNF-α and IL-8 was observed. These data suggest that most mild infections are associated with absence of inflammation coupled with an active innate immune response, T-cell activation and neutralizing antibodies. Assessing neutralizing capacity of antibodies 146 We next assessed whether the antibodies detected in these patients were capable of 147 neutralizing the wild type virus isolated from one of the patients. We performed plaque natural infection or vaccination is a major concern to tackle the ongoing pandemic (16, 162 17). 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