PREVALENCE AND CLINICAL CHARACTERISTICS OF INFLUENZA AND OTHER RESPIRATORY VIRAL INFECTIONS: A RETROSPECTIVE OBSERVATIONAL STUDY

Abstract

Background: Influenza and other respiratory viruses are major contributors to global
morbidity and mortality, particularly among vulnerable populations. This study aims
to analyse the prevalence, demographic distribution, and clinical characteristics of
influenza and co-circulating respiratory viruses, including COVID-19, in a cohort of
symptomatic patients.
Methods:A retrospective observational study was conducted at Government Medical
College, Department of Virology, Amritsar. A total of 551 patients were included
based on predefined eligibility criteria. Clinical symptoms, comorbidities, and
demographic data were collected. Laboratory diagnosis was performed using RTPCR, rapid antigen testing, and viral culture to detect Influenza A (IAV), Influenza B
(IBV), H1N1, H3N2, SARS-CoV-2, and other respiratory viruses. Statistical analyses
were performed using descriptive and inferential methods, with significance set at p
< 0.05.
Results:Among the 296 patients, the most common symptoms were fever, cough,
sore throat, headache, and breathlessness (93.2%). The majority of cases occurred in
the 6–64 years age group (81.9%), followed by ≥65 years (18.3%) and ≤5 years
(3.6%). Influenza A was the most frequently detected virus (119 cases), with H1N1
(49 cases) and H3N2 (6 cases) as the dominant subtypes. COVID-19 was identified
in 16 cases, while other respiratory viruses, including RSV, adenovirus, and human
metapneumovirus, were detected at lower frequencies. Patients with comorbidities
such as lung disease, diabetes, and heart disease had a higher prevalence of
infections.
Conclusion:Influenza A, particularly H1N1 and IAV, was the predominant
respiratory virus in this study, affecting mostly adults. The co-circulation of SARSCoV-2 and other respiratory viruses underscores the need for comprehensive
surveillance and multiplex testing to improve diagnosis and treatment strategies.
Findings from this study highlight the importance of targeted vaccination programs
and early intervention in high-risk populations.