Varsha Potdar

Background: Acute respiratory infections (ARIs) are a leading cause of infant morbidity and hospitalization, with respiratory viruses being the predominant etiological agents. Data on clinical profile and outcomes of viral ARIs in term infants from India remain limited. Our objective was to evaluate the epidemiology, clinical profile, laboratory profile, and outcomes of respiratory syncytial virus (RSV) and other viral ARIs in hospitalized infants (aged ≤ 12 months) born at term (>37 weeks gestation). Methods: This prospective, multicenter, hospital-based observational study was conducted in Eastern India between July 2023 and March 2025. Respiratory viruses were detected using real-time RT-PCR. Demographic, clinical, laboratory, radiological, treatment, and outcome data were analyzed. RSV-positive infants were compared with RSV-negative infants and with infants infected with other respiratory viruses. Results: Among 224 infants, respiratory viruses were detected in 56.3%, with RSV being the most common pathogen (19.6%). Compared with infants infected with other respiratory viruses, RSV-positive infants had a significantly higher frequency of fast breathing (72.7% vs. 53.6%, p = 0.03), higher levels of inflammatory markers, and a longer median hospital stay (8 vs. 6 days, p = 0.02). In exploratory multivariable analysis, RSV infection (adjusted OR [aOR] 2.4, 95% CI 1.3–6.1), low-flow oxygen requirement at admission (aOR 1.9, 95% CI 1.4–5.3), and feeding difficulty (aOR 1.3, 95% CI 1.0–2.9) were independently associated with severe disease. Conclusions: RSV was the leading viral cause of ARI in hospitalized term infants and was associated with greater respiratory involvement, a heightened inflammatory response, and prolonged hospitalization compared with other viruses. These findings highlight the importance of early recognition and appropriate supportive care in hospitalized term infants with RSV infection.

Acute respiratory illness (ARI) is one of the most common illnesses globally, affecting all age groups and leading to both upper respiratory tract infectio

Background & objectives: A three-year-old male child from West Bengal, India, with severe acute respiratory symptoms, was confirmed in the laboratory with LPAI H9N2 virus infection under the Indian Council of Medical Research (ICMR) - Pan India Acute Respiratory Infections (ARI) / Severe Acute Respiratory Infections (SARI) surveillance through the Virus Research and Diagnostic Laboratories network. Methods: Common respiratory viruses were detected by real-time PCR, followed by subtyping of Influenza A for seasonal and avian viruses. The identified H9N2 virus was isolated and further characterised, including whole genome sequencing. Antibody response was performed in serum samples of the case and family members. Results: Complete genome sequencing revealed a G1 lineage (Middle East B sub-lineage). Bayesian evolutionary analyses of the HA gene of Indian H9N2 poultry strains showed three clusters of multiple introductions at the estimated node age of 1999 based on the Human strain A/India/NIV/1519/2024(H9N2) and the other poultry viruses from India evolved with 4.49 × 10^–3 substitutions per site per year. The isolated H9N2 virus showed a high EID₅₀ titre of 10^8.25/200 µl with avian-type receptor specificity. The antibodies against the H9N2 virus were only detected in the study case and not in close contacts confirming limited human-to-human transmission. The virus was found to be sensitive to neuraminidase inhibitors oseltamivir and zanamivir. Interpretation & conclusions: Systematic avian influenza surveillance in both birds and humans is required for the early detection of newly evolved viruses.

Acute respiratory infections (ARIs) are a leading cause of death in children under five globally. The seasonal trends and profiles of respiratory viruses vary by region and season. Due to limited information and the population’s vulnerability, we conducted the hospital-based surveillance of respiratory viruses in Eastern Uttar Pradesh. Throat and nasal swabs were collected from outpatients and inpatients in the Department of Paediatrics, Baba Raghav Das (BRD) Medical College, Gorakhpur, between May 2022 and April 2023. A total of 943 samples from children aged 1 to 60 months were tested using multiplex real-time PCR for respiratory viruses in cases of ARI and SARI. Out of 943 samples tested, the highest positivity was found for parainfluenza virus [105 (11.13%) PIV-1 (79), PIV-2 (18), PIV-4 (18)], followed by adenovirus [82 (8.7%), RSV-B, [68 (7.21%)], influenza-A [46(4.9%): H1N1 = 29, H3N2 = 14), SARS CoV-2 [28 (3%)], hMPV [13(1.4%), RSV-A [4 (0.42%), and influenza-B (Victoria lineage) 1 (0.10%). The maximum positivity of respiratory viruses was seen in children between 1 to 12 months. The wide variation in prevalence of these respiratory viruses was seen in different seasons. This study enhances understanding of the seasonal and clinical trends of respiratory virus circulation and co-infections in Eastern Uttar Pradesh. The findings highlight the importance of targeted interventions to reduce the burden of respiratory infections in this region.

Background: Respiratory viral illnesses among children are a prominent cause of morbidity and mortality in the developing world. The aim of this study is to understand the seasonal pattern and surge of respiratory viruses among the Nicobarese tribe. Methods: Respiratory specimens were collected from both ARI and SARI cases attended the BJR district hospital in Car Nicobar Island, India, between 2021 and 2022. Respiratory viruses were identified from the specimens by using the qRT-PCR assay. Meteorological parameters were collected and evaluated using Microsoft Excel and SPSS 21. The significant association between the surge of respiratory viruses and each climatic parameter was evaluated. Results: In this hospital-based cross-sectional study, 471 ILI cases were enrolled, and 209 of these were positive for respiratory viral infections. Of these respiratory virus infections, 201 (96.2%) were infected with a single respiratory virus infection, and 8 (3.8%) had mixed viral infections. Fever, cough, and chills were the most common symptoms of respiratory illness among this indigenous population. There was a significant link between respiratory viruses and influenza-like illness in children (below 5 years and 6 to 15 years). Conclusion: This prevalence study revealed that viral respiratory infections were more common in children than adults. Among these respiratory viruses, respiratory syncytial virus A (RSV) and influenza B virus were predominantly reported among tribal children up to age five years. In the year 2021, these viruses were recorded frequently during the winter season. Climate factors such as high humidity, high precipitation, moderate temperature, and moderate rainfall are found to be correlated with respiratory viral infections. This study implicates important information for preventing a further outbreak of respiratory viral infections in Car Nicobar Island.

Introduction: Respiratory Syncytial Virus (RSV) is a leading cause of acute lower respiratory infection in children worldwide. Understanding its prevalence, variations, and characteristics is vital, particularly in the context of the COVID-19 pandemic. Objective: The study aimed to investigate the RSV positivity rate, subtype prevalence, age and gender distribution, symptomatology, and co-infection rates during pre-pandemic and pandemic periods. Methods: We analyzed data from 15,381 patients tested for RSV between 2017 and 2023. Results: Our analysis revealed a 7.2% average RSV positivity rate in the pre-pandemic period, with significant fluctuations during the pandemic (1.5% in 2020 to 32.0% in 2021). We observed variations in RSVA and RSVB detection rates. The 0–4 years’ age group was consistently the most affected, with a slight male predominance. Fever and cough were common symptoms. Therapeutic interventions, particularly antiviral usage and ventilation requirements, decreased during the pandemic. We also identified variations in co-infection rates with other respiratory viruses. Conclusion: Our study offers critical insights into the impact of the COVID-19 pandemic on RSV prevalence, subtype distribution, patient characteristics, and clinical management. These findings underscore the need for ongoing surveillance and adaptive public health responses.

Background: Limited data exists regarding risk factors for adverse outcomes in older adults hospitalized with Community-Acquired Pneumonia (CAP) in low- and middle-income countries such as India. This multisite study aimed to assess outcomes and associated risk factors among adults aged ≥60 years hospitalized with pneumonia. Methods: Between December 2018 and March 2020, we enrolled ≥60-year-old adults admitted within 48 hours for CAP treatment across 16 public and private facilities in four sites. Clinical data and nasal/oropharyngeal specimens were collected by trained nurses and tested for influenza, respiratory syncytial virus (RSV), and other respiratory viruses (ORV) using the qPCR. Participants were evaluated regularly until discharge, as well as on the 7th and 30th days post-discharge. Outcomes included ICU admission and in-hospital or 30-day post-discharge mortality. A hierarchical framework for multivariable logistic regression and Cox proportional hazard models identified risk factors (e.g., demographics, clinical features, etiologic agents) associated with critical care or death. Findings: Of 1,090 CAP patients, the median age was 69 years; 38.4% were female. Influenza viruses were detected in 12.3%, RSV in 2.2%, and ORV in 6.3% of participants. Critical care was required for 39.4%, with 9.9% in-hospital mortality and 5% 30-day post-discharge mortality. Only 41% of influenza CAP patients received antiviral treatment. Admission factors independently associated with ICU admission included respiratory rate >30/min, blood urea nitrogen>19mg/dl, altered sensorium, anemia, oxygen saturation <90%, prior cardiovascular diseases, chronic respiratory diseases, and private hospital admission. Diabetes, anemia, low oxygen saturation at admission, ICU admission, and mechanical ventilation were associated with 30-day mortality. Conclusion: High ICU admission and 30-day mortality rates were observed among older adults with pneumonia, with a significant proportion linked to influenza and RSV infections. Comprehensive guidelines for CAP prevention and management in older adults are needed, especially with the co-circulation of SARS-CoV-2.

A globally implemented unified classification for human respiratory syncytial virus (HRSV) below the subgroup level remains elusive. Here, we formulate the global consensus of HRSV classification based on the challenges and limitations of our previous proposals and the future of genomic surveillance. From a high-quality dataset of 1,480 HRSV-A and 1,385 HRSV-B genomes submitted to NCBI and GISAID up to March 2023, we categorized HRSV-A/B sequences into lineages based on phylogenetic clades and amino acid markers. We defined 24 lineages within HRSV-A and 16 within HRSV-B, providing guidelines for prospective lineages definition. Our classification demonstrated robustness in its applicability to both complete and partial genomes. In addition, it allowed the observation of notable lineage replacements and the identification of lineages exclusively detected since the COVID-19 pandemic. We envision that this unified HRSV classification proposal will strengthen and facilitate HRSV molecular epidemiology on a global scale.