Respiratory viruses are the common causative agents leading to high morbidity and mortality due to respiratory infection which impose a heavy economic burden . Respiratory viruses cause varying degrees of respiratory diseases among all age groups and it includes respiratory syncytial virus (RSV), influenza virus, parainfluenza virus, human metapneumovirus (HMPV), rhinovirus, adenovirus and corona virus [2, 3, 4]. These respiratory viruses can be transmitted via direct or indirect contact, droplets and aerosols. SARS CoV-2, the cause of the epidemic in Wuhan, China in December 2019, has spread around the world, causing significant morbidity and mortality. The World Health Organization (WHO) classified COVID-19 a public health emergency of worldwide significance on January 31, 2020 . It was discovered that the COVID19 pandemic was linked to changes in a wide spectrum of respiratory viruses. Although, acute respiratory infections (ARI) caused by seasonal viruses shows lower positivity rates during COVID-19 pandemic in South Korea .
Adopting Non-pharmaceutical interventions (NPIs) such as wearing face-mask, closure of schools, shops and places of public gatherings and restriction of movements might influence the incidence of varying degrees of respiratory viral infections . In the US, the number of influenza like illness has reduced for the period of 2019 – 2020 . In many industrialised and developing countries, influenza-related hospitalisation rates have declined even during pandemic . Recent studies have discovered that SARS CoV-2 and other respiratory viruses co-infect at higher rates . During a COVID pandemic, frequently identified viruses can still exist and induce co infection. Some studies reported quite a low percentage of SARS CoV-2 co-infection with no increase in mortality and morbidity. However, the alteration in viral aetiology and epidemiologic features of respiratory infections during pandemic need to be explored . Routine testing for non-SARS-CoV-2 respiratory viruses during COVID-19 pandemic could help with disease management. Surveillance of ARI requiring hospital treatment is becoming more critical for the detection of novel respiratory viruses. Age related factors were focused to know the predominant age groups prone to infectious respiratory viruses. Paediatric and elderly patients were more commonly affected by this respiratory illness because of low immune response and other related factors [9, 10].
Andaman and Nicobar Islands, a Union Territory of India, is an archipelago of 555 islands/islets stretching over 435 miles from north to south in the Bay of Bengal, and is 841 miles away from mainland India in Bay of Bengal. Those islands are situated about 93 miles from north of Aceh in Indonesia and is nearer to Thailand and Burma. There are 38 human-inhabited islands, with two unique ancient groups of tribes : Mongoloids in the Nicobar (Nicobarese and Shompens), and Negretoes in the Andaman (Jarawas, Great Andamanese, Onges and Sentinelese) .
Car Nicobar is a small(49km2 ) remote island and is connected to Port Blair with ship as well as air, and is 260 km from the headquarter of Port Blair, Andaman, and the Nicobar Islands, India. Car Nicobar Island's climate is tropical, as it is only 9 degrees south of the equator and it is the home for the aboriginal tribe Nicobarese, one of the six aboriginal tribes and inhabits a population of 17,841 (>98% Nicobarese) as per census 2011 . The living type of the Nicobarese is called “TUHET” or large joint family. The entry to this island is restricted for the common public and tourists. However, the people of Nicobarese tribe is allowed to travel all over the country . Health care services in this island are entirely under the government sector through Directorate of Health Services. BJR district hospital is the only major health facility in this island .
There is always a risk of spread of any respiratory viruses to this island due to the movement of this tribe to all over the country and significant increase of tourists in Andaman Islands, especially to the head quarter Port Blair.
Keeping in view of history of influenza H1N1 pandemic the surveillance activities were strengthened in Car Nicobar . The first incidence of COVID-19 infection reported in Kerala on January 31, 2020 . SARS CoV-2 was later discovered in all of India states consequently. The first case of SARS CoV-2 was detected on 8 August, 2020 in Car Nicobar Island, however, the spread was contained and there were no reported cases of SARS CoV-2 from December 2020. Travel from mainland India and overseas was restricted during the COVID-19 pandemic. Meanwhile the study was started prior to the pandemic in Car Nicobar Island between June 2019 and May 2021. This research intended to quantify the occurrence of common respiratory viruses among Nicobarese tribe during COVID-19 pandemic and pre-pandemic in the hospital settings of Car Nicobar Island, India.