Molecular characterization of human respiratory syncytial virus NA1 and GA5 genotypes detected in Assam in northeast India, 2009-2012

Characterizing human respiratory syncytial virus among children admitted with acute respiratory tract infections from 2019 to 2022

Respiratory syncytial virus is a major causative agent of lower respiratory tract infection in children, especially infants with substantial morbidity and mortality implications. The virus undergoes continuous evolution documented by accumulation of mutations in the glycoprotein gene necessitating vigilant surveillance to provide essential data to epidemiologists and researchers involved in development of vaccines. This study was aimed to perform molecular characterization of respiratory syncytial virus (RSV) among children ≤ 5 years admitted in hospital. In the current study we observed RSV-A (2019 (n = 95) and 2021 (n = 61) seasons) and RSV-B (2022 season (n = 68)). Phylogenetic analysis revealed all RSV-A strains (n = 47) to be GA.2.3.5 and RSV-B (n = 22) were classified as GB.5.0.5a. Selection pressure analysis identified one positive (P274L/V) and one negative site (P230T) in RSV-A, while in RSV-B there was only one negatively selected site (S295). This study spanning over three seasons contributes to RSV evolutionary dynamics in India emphasizing the importance of on-going surveillance to inform effective public health strategies and vaccine development efforts.

Reclassification of respiratory syncytial virus genotypes in India

Respiratory syncytial virus (RSV) is known to be the major cause of lower respiratory tract infections in infants and in the elderly. RSV was recently reclassified and simplified into three genotypes of the RSV-A subgroup (GA1-GA3) and into seven genotypes of the RSV-B subgroup (GB1-GB7). This classification strategy was not implemented globally. This study intended to reclassify the sequences that were submitted in GenBank till September 2021 from India. The gene sequences of the ectodomain region, second hypervariable region (SHR), and the partial second hypervariable region (PSHR) of the G gene were selected for the analysis. 25 ectodomain, 36 s hypervariable, and 19 partial second hypervariable regions of the RSV-A subgroup and 42-ectodomain, 49-s hypervariable region and 11-partial second hypervariable region of RSV-B subgroup were used for phylogenetic analysis. P-distance was calculated to support the genotype determination done by phylogenetic analysis. Phylogenetic analysis revealed that GA2.3.1, GA2.3.3, GA2.3.4, GA2.3.5, and GA2.3.6b lineages of GA2 genotype for RSV-A; and GB5.0.1, GB5.0.2, GB5.0.3, GB5.0.4a, GB5.0.4c, GB5.0.5a, GB5.0.5c lineages of GB5 genotype and GB7 genotype for RSV-B were that circulated in India. This work has implication for RSV vaccine research, and also for strategies for the prevention and control of RSV infection in humans.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13337-022-00802-x.

Pre COVID-19 molecular epidemiology of respiratory syncytial virus (RSV) among children in Bangladesh

Epidemiological data of specific respiratory pathogens from the pre-COVID-19 period are essential to determine the effects of the COVID-19 pandemic on other respiratory infections. In this study, we revealed the pre-COVID-19 molecular epidemiology of respiratory syncytial virus (RSV) among children in Bangladesh. We tested 3170 samples collected from 2008 to 2012 for a panel of respiratory viruses; RSV, human metapneumovirus (hMPV), human parainfluenza viruses (hPIV) 1, 2, 3, and adenovirus. Five hundred fifty-five samples (17.5 %) were positive for RSV, including 2.5% having co-infections with other viruses. Genotypic characterization of RSV showed that RSV-A (82%) contributed more acute respiratory infections than RSV-B (18%). Clinical features were similar with RSV-A and RSV-B infections. However, children with RSV-B were more likely to have upper respiratory infections (URI) (10% vs. 29%, p = 0.03). Among RSV-A cases, hospitalization was higher for ON1 cases (25%, ON1 vs. 8%, NA1, p = 0.04), whereas the recovery without a disability was higher among the NA1 cases (56%, ON1 vs. 88%, NA1, p = 0.02). The time to the most recent common ancestor (TMRCA) for RSV in Bangladesh was 1949 for RSV-A and 1944 for RSV-B. This study revealed the genotypic diversity and evolutionary relatedness of RSV strains in Bangladesh and provided pre-COVID molecular epidemiology data to understand better the COVID-19 impact on upcoming RSV epidemiology in Bangladesh.

Genotyping of respiratory syncytial virus among influenza-like illness and severe acute respiratory infection cases of children in the Philippines from 2006 to 2016

Objective

Respiratory syncytial virus (RSV) is a leading cause of severe lower respiratory infection, and therefore, a major threat to global health. This study determined the epidemiological and molecular characteristics of RSV among cases of influenza‐like illness (ILI) and severe acute respiratory infection (SARI) among children in the Philippines.

Method

The study included archived nasopharyngeal swab and oropharyngeal swab samples collected from patients under the age of five who are presented with ILI or SARI for the period of 2006–2016. Swabs were examined for RSV subgroup by multiplex real‐time qRT‐PCR. Partial genome sequencing and phylogenetic analyses of the second hypervariable region (HVR) of the G gene were used to determine the genotype of RSV isolates.

Results

A total of 1036 representative samples from all sites were selected and tested. Of these samples, 122 were RSV‐positive at 11.8% prevalence rate, and 58.2% (71/122) were classified as RSV‐A. Six genotypes were identified, which include NA1 (27/122, 22.1%), ON1 (5/122, 4.1%), GA2 (1/122, 0.8%), and GA5 (1/122, 0.8%) for RSV‐A; and BA2 (13/122, 10.7%) and BA9 (1/122, 0.8%) for RSV‐B. Most RSV‐related cases were significantly associated with clinical characteristics such as runny nose (88.1% RSV vs. 11.9% non‐RSV: p value = 0.021), pneumonia (80.6% RSV vs. 19.4% non‐RSV; p value = 0.015), and bronchitis (71.7% RSV vs. 28.3% non‐RSV; p value < 0.001). Increased RSV‐related cases were observed among children below 24 months old.

Conclusion

The RSV trend and genetic variability in the Philippines resembles a similar pattern of transmission globally.

Respiratory syncytial virus infection in children and its correlation with climatic and environmental factors

OBJECTIVE

In this study, we aimed to investigate the clinical epidemiology of lower respiratory tract infections with different respiratory syncytial virus (RSV) subtypes in hospitalized children in Suzhou and their correlation with climatic and environmental factors.

METHOD

In this retrospective cross-sectional study, we collected nasopharyngeal secretion samples from children hospitalized with acute lower respiratory tract infection. We collected the clinical data of children with RSV infection, and compared and analyzed their epidemiological characteristics.

RESULTS

RSV-B was the dominant strain in 2016. In 2018, RSV-A was the dominant strain. The positive detection rate of RSV-A was negatively correlated with monthly mean temperature, monthly mean wind speed, total monthly rainfall, and O₃ concentration and positively correlated with PM2.5, PM10, and NO₂, SO₂, and CO concentrations. The positive detection rate of RSV-B was negatively correlated with monthly average temperature, monthly total rainfall, monthly sunshine duration, and O₃ concentration and positively correlated with CO concentration.

CONCLUSIONS

RSV-A was the main subtype detected in this study. The positive detection rate of RSV-A was related to temperature, wind speed, rainfall, PM2.5. PM10, and NO₂, SO₂, CO, and O₃ concentrations. The positive detection rate of RSV-B was related to temperature, rainfall, sunshine time, and O₃ concentration.

Molecular epidemiology of respiratory syncytial virus among children and adults in India 2016 to 2018

Respiratory syncytial virus (RSV) is a common cause of respiratory tract infections among children less than 5 years of age and the elderly. This study intended to determine the circulating genotypes of RSV among severe acute respiratory illness (SARI) cases during the period 2016–2018 in India, among hospitalized acute febrile illness cases of age ranging from 1 to 65 years. Throat/nasopharyngeal swab samples were subjected for testing RSV and subgroups by real-time reverse transcriptase polymerase chain reaction (RT-PCR), further sequencing and phylogenetic analysis were performed for the second hypervariable region of the G gene. RSV-A and B subtypes co-circulated during the years 2016, 2017, and 2018, with RSV-A as the dominant subtype in 2016, and RSV-B as the dominant subgroup in 2017 and 2018. Phylogenetic analysis revealed that the circulating genotypes of RSV were GA2 (16/16), of RSV-A, and GB5 (23/23) of RSV-B in the South, North, and Northeast region of India during the period between 2016 and 2018. Here we report the first study comprising the distribution of RSV-A and B genotypes in the different geographic regions of India among children and adults during the year 2016 to 2018. We also report GA2.3.7 lineage of GA2 genotype for the first time in India to the best of our knowledge.

Disease Burden Due to Respiratory Syncytial Virus in Indian Pediatric Population: A Literature Review

Respiratory syncytial virus (RSV) is one of the leading causes of lower respiratory tract infections in young children. Globally, there is huge disease burden, high treatment cost, and health impact beyond acute episodes due to RSV which necessitate development and implementation of preventive strategies for the control of RSV infection. The disease burden due to RSV in pediatric population across India is still not clearly understood so this literature review was therefore conducted to gather data on disease burden due to RSV in Indian pediatric population. Systematic literature search was performed using PubMed and Google search with different medical subject headings from 2007 to 2020. Studies performed in Indian pediatric population were selected for review. Literature review revealed that in India, epidemiology of RSV infection is well documented in young children (0-5 years) as compared to children from other age groups. The rates of RSV detection in various studies conducted in younger children (0-5 years) vary from 2.1% to 62.4% in India which is higher as compared to children from other age groups. In India, RSV mainly peaks around rainy to early winter season, that is, during months of June through October while smaller peak was noted during December, January, and February. In 2020, higher RSV-associated disease burden was reported among children (<5 years) in low-income and lower-middle-income countries. Considering significant disease burden due to RSV in young Indian children, availability of RSV vaccine would be crucial to prevent RSV infections in children and its spread in the community.

Epidemiology and phylogenetic analysis of respiratory viruses from 2012 to 2015 - A sentinel surveillance report from union territory of Puducherry, India

Background

Acute respiratory infections (ARI) are the most common illnesses affecting people of all ages worldwide. Viruses contribute to 30–70% of acute respiratory infections. Identification of these respiratory viruses is not given high priority except influenza; however, the knowledge about prevalence of non-influenza viruses, their seasonal pattern and genetic evolution have significant epidemiological value.

Methods

As a part of National Influenza-like illness surveillance programme, respiratory specimens were collected children and adults with symptoms of ILI or ARI, between January 2012 and March 2015 (including SARI cases). Real-time PCR was done to identify 13 respiratory viruses. Sequencing was done for representative isolates of each virus using ABI 3730 Genetic Analyzer.

Results

During the study period between January 2012 and March 2015, a total of 648 patients with symptoms of ARI were included in this study. The mean age of the patients was 20.2 years (SD = 19.13, median = 18); 292 (45.1%) were children (≤13 years) and 356 (54.9%) were adults. Respiratory viruses were identified in 44% (287/648) of all patients. Influenza accounted for the maximum number of cases- 179/648 (27.6%). Among the non-influenza viruses, RSV predominated with 34 cases (5.2%), followed by HMPV 24 (3.7%) and PIV-3 20 (3%). Four patients died due to INF A/H1N1 (2012-2, 2015-2) as a result of acute respiratory distress syndrome (ARDS) (CFR 3.7%). Among the non-influenza viruses, no particular seasonality pattern was observed over the different months of the study period.

Conclusion

Antibiotic usage in treating acute respiratory infections empirically is not justified as nearly half of ARI are due to viruses; nearly 28% of them were due to influenza viruses. Among the non-influenza viruses, RSV predominated, followed by HMPV. This study is based on an active influenza surveillance initiated after 2009 pandemic influenza outbreak, in the Union territory of Puducherry which has contributed significantly to the knowledge of the burden of influenza and non-influenza viruses among children and adults. Such surveillance network has paved the way for better diagnosis and timely therapeutic interventions.

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First data on the epidemiology of respiratory viruses from this region after 1974.

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First study to report corona virus, HCoV OC43 from India, and only the second Indian study to document corona virus, HCoV229E. This study is the first study to analyse the genetic sequence of HCoV-229E and OC-43.

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Influenza accounted for the maximum number of cases in the study population, 27%; four patients died of Acute respiratory distress syndrome (ARDS) due to influenza A/H1N1; CFR- 3.7%.

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Among the non-influenza viruses, RSV pre-dominated followed HMPV and PIV-3. No deaths were reported due to non-influenza viral ARI. RSV was detected almost equally in adults and children.

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Distinct pattern was observed in seasonality of influenza viruses but not for non-influenza viruses.

Respiratory syncytial virus infections in India: Epidemiology and need for vaccine

Respiratory syncytial virus (RSV) has been identified as a leading cause of lower respiratory tract infections in young children and elderly. It is an enveloped negative-sense RNA virus belonging to Genus Orthopneumovirus. The clinical features of RSV infection range from mild upper-respiratory-tract illnesses or otitis media to severe lower-respiratory-tract illnesses. Current estimates show that about 33.1 million episodes of RSV-acute lower respiratory infection (ALRI) occurred in young children in 2015, of these majority that is, about 30 million RSV-ALRI episodes occurred in low-middle-income countries. In India, the rates of RSV detection in various hospital- and community-based studies mostly done in children vary from 5% to 54% and from 8% to 15%, respectively. Globally, RSV epidemics start in the South moving to the North. In India, RSV mainly peaks in winter in North India and some correlation with low temperature has been observed. Different genotypes of Group A (GA2, GA5, NA1 and ON1) and Group B (GB2, SAB4 and BA) have been described from India. The burden of RSV globally has kept it a high priority for vaccine development. After nearly 50 years of attempts, there is still no licensed vaccine and challenges to obtain a safe and effective vaccine is still facing the scientific community. The data in this review have been extracted from PubMed using the keywords RSV and Epidemiology and India. The data have been synthesised by the authors.

Genetic diversity of human respiratory syncytial virus in children with acute respiratory infections in Chennai, South India

Introduction

Human respiratory syncytial virus (HRSV) an RNA virus belonging to Pneumoviridae family, is an important cause of acute respiratory infections (ARIs) in young children. HRSV circulates as two subgroups A and B, which are further categorised into several genotypes. New genotypes may replace existing ones over successive epidemic seasons and multiple genotypes may cocirculate in the same community rendering it important to monitor them at the molecular level. The present study assessed the circulating genotypes of HRSV in Chennai.

Materials and Methods

Two hundred and sixty-seven children with ARI were recruited during the study from April 2016 to March 2018 for detecting HRSV A and B by real-time reverse transcription-polymerase chain reaction. Phylogeny and selection pressure analysis were done.

Results

Fifty-seven of the 267 samples (21.3%) were positive for HRSV, of which 7.1% and 14.2% were HRSV A and B, respectively, indicating that HRSV B was the major subgroup circulating in Chennai. Peak activity of HRSV was observed during the monsoon and winter months. Phylogenetic analysis of 2nd hypervariable region (HVR) of attachment glycoprotein gene (G gene) revealed that the HRSV A strains belonged to ON1 and HRSV B strains belonged to BA9 genotypes. Several unique amino acid substitutions were observed among the study strains. The Shannon entropy plot revealed that the HRSV A strains from our study have a high potential for amino acid substitutions in the 2nd HVR of G gene.

Conclusion

This study underlines the genetic diversity of HRSV and emphasises the need for continued molecular surveillance for infection management and prevention strategies.

Analysis of genetic variability of respiratory syncytial virus groups A and B in Kuwait

Respiratory syncytial virus (RSV) is the most frequently identified viral agent in infants, children, and elderly people with acute respiratory tract infections (ARTIs). This study is the only one of its kind in Kuwait, and its purpose was to investigate the genetic variability of the G protein gene in RSV strains prevalent in Kuwait. Respiratory samples were collected from patients with ARTIs in various hospitals in Kuwait and subjected to reverse transcription PCR (RT-PCR) amplifying a fragment of the G gene of RSV. A total of 305 samples were collected between January and mid-December 2016, and 77 (25.2%) were positive for RSV. Group A viruses were predominant over group B viruses; the RSV-A group was detected in 52 (67.5%) of the positive samples, while the RSV-B group was detected in 25 (32.5%) of the positive samples. Phylogenetic analysis showed that all RSV-A strains grouped into eight clusters of identical sequences of untyped strains. Twelve RSV-B strains, on the other hand, belonged to the RSV-B/BA10 genotype, while the rest were untyped. These data suggest that new and untyped strains of RSV-A group likely predominated in Kuwait and that the BA10 genotype of the RSV-B group became the dominant genotype in the 2016 season.

Global distribution of NA1 genotype of respiratory syncytial virus and its evolutionary dynamics assessed from the past 11 years

Respiratory syncytial virus (RSV) is a potent pathogen having global distribution. The main purpose of this study was to gain an insight into distribution pattern of the NA1 genotype of group A RSV across the globe together with its evolutionary dynamics. We focused on the second hypervariable region of the G protein gene and used the same for Phylogenetic, Bayesian and Network analyses. Eighteen percent of the samples collected from 500 symptomatic pediatric patients with acute respiratory tract infection (ARI) were found to be positive for RSV during 2011-15 from New Delhi, India. Of these, group B RSV was predominant and clustered into two different genotypes (BA and SAB4). Similarly, group A viruses clustered into two genotypes (NA1 and ON1). The data set from the group A viruses included 543 sequences from 23 different countries including 67 strains from India. The local evolutionary dynamics suggested consistent virus population of NA1 genotype in India during 2009 to 2014. The molecular clock analysis suggested that most recent common ancestor of group A and NA1 genotype have emerged in during the years 1953 and 2000, respectively. The global evolutionary rates of group A viruses and NA1 genotype were estimated to be 3.49 × 10^-3 (95% HPD, 2.90-4.17 × 10^-3) and 3.56 × 10^-3 (95% HPD, 2.91 × 10^-3-4.18 × 10^-3) substitution/site/year, respectively. Analysis of the NA1 genotype of group A RSV reported during 11 years i.e. from 2004 to 2014 showed its dominance in 21 different countries across the globe reflecting its evolutionary dynamics. The Network analysis showed highly intricate but an inconsistent pattern of haplotypes of NA1 genotype circulating in the world. Present study seems to be first comprehensive attempt on global distribution and evolution of NA1 genotype augmenting the optimism towards the vaccine development.

Molecular epidemiology of human respiratory syncytial virus among children in Japan during three seasons and hospitalization risk of genotype ON1

We investigated the genetic diversity, the circulation patterns, and risk for hospital admission of human respiratory syncytial virus (HRSV) strains in Japan between 2012 through 2015. During the study period, 744 HRSV-positive cases were identified by rapid diagnostic test. Of these, 572 samples were positive by real-time PCR; 400 (69.9%) were HRSV-A, and 172 (30.1%) were HRSV-B. HRSV-A and -B alternated as the dominant strain in the subsequent seasons. Phylogenetic tree analysis of the second hyper-variable region of the G protein classified the HRSV-A specimens into NA1 (n = 242) and ON1 (n = 114) genotypes and the HRSV-B specimens into BA9 (n = 60), and BA10 (n = 27). The ON1 genotype, containing a 72-nucleotide duplication in the G protein’s second hyper-variable region, was first detected in the 2012–2013 season but it predominated and replaced the older NA1 HRSV-A in the 2014–2015 season, which also coincided with a record number of HRSV cases reported to the National Infectious Disease Surveillance in Japan. The risk of hospitalization was 6.9 times higher for the ON1 genotype compared to NA1. In conclusion, our data showed that the emergence and predominance of the relatively new ON1 genotype in Japan was associated with a record high number of cases and increased risk for hospitalization.

Genetic characterization respiratory syncytial virus in Kerala, the southern part of India

Respiratory syncytial virus (RSV) is an important cause of acute lower respiratory tract infection (ALRI) in infants and young children globally. RSV presents two antigenic groups RSV-A and -B. Genetic variability is also very high within each group. RSV circulation varies year to year and even varies among different regions. Data on circulatory pattern of RSV are available from other parts of India except Kerala. The aim of the study was to generate data about groups and genotypes of circulating RSV in Kerala. In this study, RSV positive samples received during January, 2012 to December, 2014 were used for genetic characterization. The samples were tested by using nucleocapsid (N) gene-based conventional multiplex reverse transcriptase polymerase chain reaction (RT-PCR) to identify the RSV group. Genotyping was done by nucleotide sequencing of the C-terminal region of the glycoprotein (G) gene. Out of the 130 patient samples tested, 49 samples were positive for RSV. Among the positive samples, 32 belong to the RSV-A and 17 belong to RSV-B virus. Phylogenetic analysis revealed that all RSV-A sequences (n = 22) belonged to NA1 genotype and five of the sequences showed the novel 72 nucleotide duplication and clustered into the newly designated ON1 genotype. All RSV-B sequences (n = 17) were clustered into the BA (BA9 and 10) genotype. From this study, we concluded both RSV-A and -B were co-circulated in Kerala and RSV-A was observed predominantly in 2012 and RSV-B in 2014. As per our best of knowledge, BA10 genotype is first observed in India.

Molecular characterization of human respiratory syncytial virus detected from central India

Human Respiratory syncytial virus (hRSV) is the major cause of respiratory tract infection in both children and adults, virtually all children acquire infection with hRSV by the age of 3 years. Two subgroups of the virus, hRSV-A and hRSV-B based on sequence variability of G protein gene are divided into 11 and 17 genotypes, respectively. Very limited data regarding circulating genotypes is available from India. This study aimed to detect and characterize the circulating genotype of hRSV from central India. Throat swabs collected from patient's having influenza like illness (ILI) were subjected to RT-PCR for diagnosis, further sequencing and phylogenetic analysis was performed using primers specific for C-terminal end of G gene. Out of 526 tested samples 62 (12%) were found positive, 90% cases were from children under 3-year age children. Both hRSV-A and hRSV-B were detected in equal proportions. Sequence analysis of 15 samples revealed circulation of genotypes NA1, ON1 of hRSV-A, and BA9 of hRSV-B. We advocate molecular surveillance of hRSV for better patient management and epidemiological monitoring.

Biophysical characterization of G protein ectodomain of group B human respiratory syncytial virus from E. coli

Human respiratory syncytial virus (hRSV) is an important pathogen of acute respiratory tract infection. The G protein of hRSV is a transmembrane glycoprotein that is a neutralizing antigen and is thus a vaccine candidate. In this study, synthetic codon optimized ectodomain G protein [G(ΔTM)] of BA genotype of group B hRSV was cloned, expressed, and characterized using biophysical techniques. The molar absorption coefficient and mean residue ellipticity at 222 nm ([θ]222) of G (ΔTM) was found to be 7950 M(-1) cm(-1) and -19701.7 deg cm(2) dmol(-1) respectively. It was concluded that G(ΔTM) mainly consist of α-helix (74.9%) with some amount of β-sheet (4%). The protein was stable up to 85°C without any transition curve. However, heat-induced denaturation of G(ΔTM) resulted in total loss of β-sheet whereas not much change was observed in the α-helix part of the secondary structure. It was concluded that G(ΔTM) is an α-helical protein and it is highly stable at high temperature, but could be easily denatured using high concentrations of GdmCl/urea or acidic condition. This is the first investigation of cloning, expression, and characterization of G(ΔTM) of BA viruses from India. Structural characterization of G protein will assist in drug designing and vaccine development for hRSV.

Clinical characterization of influenza A and human respiratory syncytial virus among patients with influenza like illness

Influenza A and Respiratory Syncytial Virus (RSV) has been recognized as a major cause of acute respiratory tract infection. H1N1 is one of the subtypes of influenza A, pandemic worldwide in July 2009, causing 18,449 deaths globally. To investigate the prevalence and clinical manifestation of the influenza A, H1N1pdm09, and RSV. Throat/nasal swab collected from the patients of all age group either outpatients/inpatients having respiratory illness from 2 to 5 days. The clinical data were recorded in a predesigned questionnaire. RNA was extracted and analyzed by real time PCR at a tertiary care center, 2009-2014. Total 4,352 samples tested for influenza A and H1N1. Out of 4,352, 32.2% (median positivity 21%; range 16-41% during 6 years) were positive for influenza A and 19% were H1N1 (median positivity 16.7%; range 8.7-23% during 6 years). Total 1653 samples were analyzed for RSV from 2011 to 2014, 12% were RSV positive (median positivity 11.35%; range 10-16.3% during 4 years). Pharyngitis, dyspnea were frequent symptoms in influenza A and H1N1 (P < 0.005) whereas bronchiolitis and pneumonia were commonly present in RSV (P < 0.005). The positivity of influenza A and H1N1 was higher in age-group 21-30, whereas RSV in infant and children. H1N1 and RSV were co-circulated and have common clinical symptoms particularly in lower age group. Therefore, laboratory confirmation is necessary for further disease prognosis. Age was an important risk factor that affects the positivity of influenza A, H1N1, and RSV. Different clinical manifestation of H1N1 and RSV will be helpful for early and accurate diagnosis. J. Med. Virol. 89:49-54, 2017. © 2016 Wiley Periodicals, Inc.