Respiratory Viruses Causing Influenza Like Illness/Severe Acute Respiratory Infection During COVID-19 Pandemic

Background: Respiratory tract infections caused by viruses are among the most common diseases in humans worldwide. The diagnosis remains difficult as the symptoms overlap significantly with each other.Objectives: The objective of this study is to identify the respiratory viruses other than SARS-CoV- -2 causing Influenza-like illness (ILI) /severe acute respiratory infection (SARI) during COVID-19 pandemic.Methods: A total of 100 samples, including COVID-19 positive (n=50) and negative (n=50), were included in the study. The detailed case record form was filled for each patient including relevant history. Nasopharyngeal and Oropharyngeal swabs were subjected to standardized RT-PCR for the detection of SARS-CoV-2 followed by Multiplex RT-PCR for other respiratory viruses.Results: Other respiratory viruses causing ILI/SARI symptoms similar to SARS-CoV2 during COVID-19 pandemic in non-COVID-19 patients aged more than 18 years were found to be Human metapneumovirus (2%), Human adenovirus (1%), Human parainfluenza virus-1 (1%). The result suggested that other respiratory viral infections are significantly higher among COVID-19 negative individuals presenting with respiratory illness as compared to COVID-19 positive individuals, possibly due to viral interference and competitive advantage of SARS-CoV-2 in modulating the host immune system.Conclusion: The other respiratory viruses in SARS-CoV-2 negative patients had mild to moderate ILI/SARI symptoms, which usually do not require hospitalization but need to be monitored, especially in high-risk patients. Human metapneumovirus, Adenovirus, Parainfluenza virus-1 most commonly occured in more than 60 years age group with comorbidity which can be useful in stratification for future surveillance of other respiratory viruses in health care settings.