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.