Epidemiology and subtype analysis of respiratory syncytial virus among hospitalized children under five in Isfahan during early 2024
,
Abstract
Background and Objectives: Respiratory syncytial virus is the most common virus causing acute respiratory infections in children under 5 years old. We aimed to investigate the prevalence and circulating strains of RSV in hospitalized children in Isfahan.
Materials and Methods: Between January and May 2024, children under 5 years of age were enrolled in this study. Nasal swabs were collected from 100 children with acute respiratory infections admitted to the referral pediatric ward at Imam Hossein Children’s Hospital in Isfahan, Iran. The prevalence of circulating RSV was investigated using the RSV qPCR detection kit. The virus type was identified by RT-PCR using type A- and B-specific primers.
Results: A total of 51 (51%) samples tested positive for RSV. Among them, typing was done in 33 specimens, of which 66.6% (22/33 cases) were assigned as subtype B and 33.3% (11/33 cases) as subtype A. Infants under 6 months were most severely affected by RSV (47.1%, 24/51). RSV-positive samples peaked in February (43.1%), followed by January (29.4%).
Conclusion: The results of the current study revealed a high prevalence of RSV and co-circulation of subtypes A and B, with subtype B more prevalent among children. This highlights the importance of ongoing surveillance of RSV.
1. Tabor DE, Fernandes F, Langedijk AC, Wilkins D, Lebbink RJ, Tovchigrechko A, et al. Global Molecular Epidemiology of Respiratory Syncytial Virus from the 2017-2018 INFORM-RSV Study. J Clin Microbiol 2020; 59(1): e01828-20.
2. Niya MHK, Jeda AS, Tavakoli A, Sohani H, Tameshkel FS, Panahi M, et al. Molecular epidemiology of human respiratory syncytial virus (HRSV) in Iranian military trainees with acute respiratory symptoms in 2017. Iran J Microbiol 2020; 12: 495-502.
3. Tavakoli A, Karbalaie Niya MH, Bokharaei-Salim F, Farahmand M, Izadi M, Dorostkar R, et al. The molecular epidemiology of respiratory viruses in military trainees in Iran. Med J Islam Repub Iran 2019; 33: 40.
4. Sadeh Tehrani R, Mohammadjafari H, Alizadeh S, Naseroleslami M, Karbalaie Niya MH. The prevalence of 17 common respiratory viruses in patients with respiratory illness but negative for COVID‐19: A cross‐sectional study. Health Sci Rep 2024; 7(3): e1986.
5. Tramuto F, Maida CM, Di Naro D, Randazzo G, Vitale F, Restivo V, et al. Respiratory syncytial virus: new challenges for molecular epidemiology surveillance and vaccination strategy in patients with ILI/SARI. Vaccines (Basel) 2021; 9: 1334.
6. Shi T, McAllister DA, O'Brien KL, Simoes EA, Madhi SA, Gessner BD, et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: a systematic review and modelling study. Lancet 2017; 390: 946-958.
7. Li Y, Wang X, Blau DM, Caballero MT, Feikin DR, Gill CJ, et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet 2022; 399: 2047-2064.
8. Guo L, Deng S, Sun S, Wang X, Li Y. Respiratory syncytial virus seasonality, transmission zones, and implications for seasonal prevention strategy in China: a systematic analysis. Lancet Glob Health 2024; 12(6): e1005-e16.
9. Mazur NI, Higgins D, Nunes MC, Melero JA, Langedijk AC, Horsley N, et al. The respiratory syncytial virus vaccine landscape: lessons from the graveyard and promising candidates. Lancet Infect Dis 2018; 18(10): e295-e311.
10. Topalidou X, Kalergis AM, Papazisis G. Respiratory syncytial virus vaccines: a review of the candidates and the approved vaccines. Pathogens 2023; 12: 1259.
11. Domachowske JB, Anderson EJ, Goldstein M. The future of respiratory syncytial virus disease prevention and treatment. Infect Dis Ther 2021; 10( Suppl 1): 47-60.
12. Ruckel CE, Wolf JD, Plemper RK. Status of advanced respiratory syncytial virus antiviral therapeutics 2025. Curr Opin Virol 2025; 73: 101477.
13. Verwey C, Dangor Z, Madhi SA. Approaches to the prevention and treatment of respiratory syncytial virus infection in children: rationale and progress to date. Paediatr Drugs 2024; 26: 101-112.
14. Kieffer A, Beuvelet M, Moncayo G, Chetty M, Sardesai A, Musci R, et al. Disease burden associated with all infants in their first RSV season in the UK: a static model of universal immunization with nirsevimab against RSV-related outcomes. Infect Dis Ther 2024; 13: 2135-2153.
15. López-Lacort M, Munoz-Quiles C, Mira-Iglesias A, Xavier López-Labrador F, Garcés-Sánchez M, Escribano-López B, et al. Nirsevimab effectiveness against severe respiratory syncytial virus infection in the primary care setting. Pediatrics 2025; 155(1): e2024066393.
16. Jabagi MJ, Cohen J, Bertrand M, Chalumeau M, Zureik MJNe. Nirsevimab effectiveness at preventing RSV-related hospitalization in infants. NEJM Evid 2025; 4(3): EVIDoa2400275.
17. Ma J, Chen L, Tang S, Shi Y. Efficacy and safety of respiratory syncytial virus vaccination during pregnancy to prevent lower respiratory tract illness in newborns and infants: a systematic review and meta-analysis of randomized controlled trials. Front Pediatr 2024; 11: 1260740.
18. Tavakoli F, Izadi A, Yavarian J, Sharifi‐Zarchi A, Salimi V, Mokhtari-Azad T. Determination of genetic characterization and circulation pattern of Respiratory Syncytial Virus (RSV) in children with a respiratory infection, Tehran, Iran, during 2018-2019. Virus Res 2021; 305: 198564.
19. Malekshahi SS, Razaghipour S, Samieipoor Y, Hashemi FB, Manesh AAR, Izadi A, et al. Molecular characterization of the glycoprotein and fusion protein in human respiratory syncytial virus subgroup A: Emergence of ON-1 genotype in Iran. Infect Genet Evol 2019; 71: 166-178.
20. Ramzali M, Salimi V, Cheraghali F, Hosseini SD, Yasaghi M, Samadizadeh S, et al. Epidemiology and clinical features of respiratory syncytial virus (RSV) infection in hospitalized children during the COVID‐19 pandemic in Gorgan, Iran. Health Sci Rep 2024; 7(1): e1787.
21. Hosseinpour Sadeghi R, Pourakbari B, Mahmoudi S, Ahmadi R, Jafari E, Sajedi Moghaddam S, et al. Evaluation of common respiratory viruses other than SARS-CoV-2 in hospitalized children during the COVID-19 pandemic. BMC Infect Dis 2025; 25: 910.
22. Mohebi L, Karami H, Mirsalehi N, Ardestani NH, Yavarian J, Mard‐Soltani M, et al. A delayed resurgence of respiratory syncytial virus (RSV) during the COVID‐19 pandemic: an unpredictable outbreak in a small proportion of children in the Southwest of Iran, April 2022. J Med Virol 2022; 94: 5802-5807.
23. Eden JS, Sikazwe C, Xie R, Deng YM, Sullivan SG, Michie A, et al. Off-season RSV epidemics in Australia after easing of COVID-19 restrictions. Nat Commun 2022; 13: 2884.
24. Hernández-Rivas L, Pedraz T, Calvo C, San Juan I, Mellado MªJ, Robustillo A. Respiratory syncytial virus outbreak during the COVID-19 pandemic. How has it changed? Enferm Infecc Microbiol Clin 2023; 41: 352-355.
25. Dolores A, Stephanie G, Mercedes S NJ, Érica G, Mistchenko AS, Mariana V. RSV reemergence in Argentina since the SARS-CoV-2 pandemic. J Clin Virol 2022; 149: 105126.
26. Ujiie M, Tsuzuki S, Nakamoto T, Iwamoto N. Resurgence of respiratory syncytial virus infections during COVID-19 pandemic, Tokyo, Japan. Emerg Infect Dis 2021; 27: 2969-2970.
27. Cohen R, Ashman M, Taha M-K, Varon E, Angoulvant F, Levy C, et al. Pediatric Infectious Disease Group (GPIP) position paper on the immune debt of the COVID-19 pandemic in childhood, how can we fill the immunity gap? Infect Dis Now 2021; 51: 418-423.
28. Thindwa D, Li K, Cooper-Wootton D, Zheng Z, Pitzer VE, Weinberger DM. Global patterns of rebound to normal RSV dynamics following COVID-19 suppression. BMC Infect Dis 2024; 24: 635.
29. Abu-Raya B, Viñeta Paramo M, Reicherz F, Lavoie P. Why has the epidemiology of RSV changed during the COVID-19 pandemic? EClinicalMedicine 2023; 61: 102089.
30. Cantú-Flores K, Rivera-Alfaro G, Muñoz-Escalante JC, Noyola DE. Global distribution of respiratory syncytial virus A and B infections: a systematic review. Pathog Glob Health 2022; 116: 398-409.
31. Salimi V, Tavakoli-Yaraki M, Yavarian J, Bont L, Mokhtari-Azad T. Prevalence of human respiratory syncytial virus circulating in Iran. J Infect Public Health 2016; 9: 125-135.
32. Korsun N, Trifonova I, Madzharova I, Alexiev I, Uzunova I, Ivanov I, et al. Resurgence of respiratory syncytial virus with dominance of RSV-B during the 2022–2023 season. Front Microbiol 2024; 15: 1376389.
33. Bhardwaj S, Choudhary ML, Chadha MS, Kinikar A, Bavdekar A, Gujar N, et al. Resurgence of respiratory syncytial virus infection during COVID-19 pandemic in Pune, India. BMC Infect Dis 2024; 24: 586.
34. Madi N, Safar HA, Al-Adwani A, Sadeq M, Al-Turab M. Genomic characterization of circulating human respiratory syncytial viruses A and B in Kuwait using whole-genome sequencing. Microbiol Spectr 2024; 12(7): e0015924.
35. Tayachew A, Mekuria Z, Shure W, Arimide DA, Gebeyehu A, Berkesa T, et al. Epidemiology of respiratory syncytial virus and its subtypes among cases of influenza like illness and severe acute respiratory infection: findings from nationwide sentinel surveillance in Ethiopia. BMC Infect Dis 2025; 25: 941.
36. Rios-Guzman E, Simons LM, Dean TJ, Agnes F, Pawlowski A, Alisoltanidehkordi A, et al. Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic. Nat Commun 2024; 15: 3374.
37. Pierangeli A, Midulla F, Piralla A, Ferrari G, Nenna R, Pitrolo AMG, et al. Sequence analysis of respiratory syncytial virus cases reveals a novel subgroup-B strain circulating in north-central Italy after pandemic restrictions. J Clin Virol 2024; 173: 105681.
38. de Jesus-Cornejo J, Hechanova-Cruz RAB, Sornillo JBT, Okamoto M, Oshitani H; Viral Etiology Working Group. Prolonged RSV circulation in 2022 to 2023 associated with the emergence of a novel RSV-B clade in Biliran, Philippines. J Infect 2025; 90: 106467.
39. Huang L, Xu Y, Yang Y, Dong H, Luo Q, Chen Z, et al. Molecular epidemiology and clinical characteristics of respiratory syncytial virus in hospitalized children during winter 2021–2022 in Bengbu, China. Front Public Health 2024; 11: 1310293.
40. Wildenbeest JG, Billard M-N, Zuurbier RP, Korsten K, Langedijk AC, van de Ven PM, et al. The burden of RSV in healthy term-born infants in Europe: a prospective birth cohort study. Lancet Respir Med 2023; 11: 341-353.
41. Patton ME, Moline HL, Whitaker M, Tannis A, Pham H, Toepfer AP, et al. Interim Evaluation of Respiratory Syncytial Virus Hospitalization Rates Among Infants and Young Children After Introduction of Respiratory Syncytial Virus Prevention Products—United States, October 2024–February 2025. MMWR Morb Mortal Wkly Rep 2025; 74: 273-281.
42. Laham FR, Mansbach JM, Piedra PA, Hasegawa K, Sullivan AF, Espinola JA, et al. Clinical profiles of respiratory syncytial virus subtypes A and B among children hospitalized with bronchiolitis. Pediatr Infect Dis J 2017; 36: 808-810.
43. Bechini A, Salvati C, Bonito B, Del Riccio M, Stancanelli E, Bruschi M, et al. Costs and healthcare utilisation due to respiratory syncytial virus disease in paediatric patients in Italy: A systematic review. Public Health 2024; 227: 103-111.
2. Niya MHK, Jeda AS, Tavakoli A, Sohani H, Tameshkel FS, Panahi M, et al. Molecular epidemiology of human respiratory syncytial virus (HRSV) in Iranian military trainees with acute respiratory symptoms in 2017. Iran J Microbiol 2020; 12: 495-502.
3. Tavakoli A, Karbalaie Niya MH, Bokharaei-Salim F, Farahmand M, Izadi M, Dorostkar R, et al. The molecular epidemiology of respiratory viruses in military trainees in Iran. Med J Islam Repub Iran 2019; 33: 40.
4. Sadeh Tehrani R, Mohammadjafari H, Alizadeh S, Naseroleslami M, Karbalaie Niya MH. The prevalence of 17 common respiratory viruses in patients with respiratory illness but negative for COVID‐19: A cross‐sectional study. Health Sci Rep 2024; 7(3): e1986.
5. Tramuto F, Maida CM, Di Naro D, Randazzo G, Vitale F, Restivo V, et al. Respiratory syncytial virus: new challenges for molecular epidemiology surveillance and vaccination strategy in patients with ILI/SARI. Vaccines (Basel) 2021; 9: 1334.
6. Shi T, McAllister DA, O'Brien KL, Simoes EA, Madhi SA, Gessner BD, et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: a systematic review and modelling study. Lancet 2017; 390: 946-958.
7. Li Y, Wang X, Blau DM, Caballero MT, Feikin DR, Gill CJ, et al. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet 2022; 399: 2047-2064.
8. Guo L, Deng S, Sun S, Wang X, Li Y. Respiratory syncytial virus seasonality, transmission zones, and implications for seasonal prevention strategy in China: a systematic analysis. Lancet Glob Health 2024; 12(6): e1005-e16.
9. Mazur NI, Higgins D, Nunes MC, Melero JA, Langedijk AC, Horsley N, et al. The respiratory syncytial virus vaccine landscape: lessons from the graveyard and promising candidates. Lancet Infect Dis 2018; 18(10): e295-e311.
10. Topalidou X, Kalergis AM, Papazisis G. Respiratory syncytial virus vaccines: a review of the candidates and the approved vaccines. Pathogens 2023; 12: 1259.
11. Domachowske JB, Anderson EJ, Goldstein M. The future of respiratory syncytial virus disease prevention and treatment. Infect Dis Ther 2021; 10( Suppl 1): 47-60.
12. Ruckel CE, Wolf JD, Plemper RK. Status of advanced respiratory syncytial virus antiviral therapeutics 2025. Curr Opin Virol 2025; 73: 101477.
13. Verwey C, Dangor Z, Madhi SA. Approaches to the prevention and treatment of respiratory syncytial virus infection in children: rationale and progress to date. Paediatr Drugs 2024; 26: 101-112.
14. Kieffer A, Beuvelet M, Moncayo G, Chetty M, Sardesai A, Musci R, et al. Disease burden associated with all infants in their first RSV season in the UK: a static model of universal immunization with nirsevimab against RSV-related outcomes. Infect Dis Ther 2024; 13: 2135-2153.
15. López-Lacort M, Munoz-Quiles C, Mira-Iglesias A, Xavier López-Labrador F, Garcés-Sánchez M, Escribano-López B, et al. Nirsevimab effectiveness against severe respiratory syncytial virus infection in the primary care setting. Pediatrics 2025; 155(1): e2024066393.
16. Jabagi MJ, Cohen J, Bertrand M, Chalumeau M, Zureik MJNe. Nirsevimab effectiveness at preventing RSV-related hospitalization in infants. NEJM Evid 2025; 4(3): EVIDoa2400275.
17. Ma J, Chen L, Tang S, Shi Y. Efficacy and safety of respiratory syncytial virus vaccination during pregnancy to prevent lower respiratory tract illness in newborns and infants: a systematic review and meta-analysis of randomized controlled trials. Front Pediatr 2024; 11: 1260740.
18. Tavakoli F, Izadi A, Yavarian J, Sharifi‐Zarchi A, Salimi V, Mokhtari-Azad T. Determination of genetic characterization and circulation pattern of Respiratory Syncytial Virus (RSV) in children with a respiratory infection, Tehran, Iran, during 2018-2019. Virus Res 2021; 305: 198564.
19. Malekshahi SS, Razaghipour S, Samieipoor Y, Hashemi FB, Manesh AAR, Izadi A, et al. Molecular characterization of the glycoprotein and fusion protein in human respiratory syncytial virus subgroup A: Emergence of ON-1 genotype in Iran. Infect Genet Evol 2019; 71: 166-178.
20. Ramzali M, Salimi V, Cheraghali F, Hosseini SD, Yasaghi M, Samadizadeh S, et al. Epidemiology and clinical features of respiratory syncytial virus (RSV) infection in hospitalized children during the COVID‐19 pandemic in Gorgan, Iran. Health Sci Rep 2024; 7(1): e1787.
21. Hosseinpour Sadeghi R, Pourakbari B, Mahmoudi S, Ahmadi R, Jafari E, Sajedi Moghaddam S, et al. Evaluation of common respiratory viruses other than SARS-CoV-2 in hospitalized children during the COVID-19 pandemic. BMC Infect Dis 2025; 25: 910.
22. Mohebi L, Karami H, Mirsalehi N, Ardestani NH, Yavarian J, Mard‐Soltani M, et al. A delayed resurgence of respiratory syncytial virus (RSV) during the COVID‐19 pandemic: an unpredictable outbreak in a small proportion of children in the Southwest of Iran, April 2022. J Med Virol 2022; 94: 5802-5807.
23. Eden JS, Sikazwe C, Xie R, Deng YM, Sullivan SG, Michie A, et al. Off-season RSV epidemics in Australia after easing of COVID-19 restrictions. Nat Commun 2022; 13: 2884.
24. Hernández-Rivas L, Pedraz T, Calvo C, San Juan I, Mellado MªJ, Robustillo A. Respiratory syncytial virus outbreak during the COVID-19 pandemic. How has it changed? Enferm Infecc Microbiol Clin 2023; 41: 352-355.
25. Dolores A, Stephanie G, Mercedes S NJ, Érica G, Mistchenko AS, Mariana V. RSV reemergence in Argentina since the SARS-CoV-2 pandemic. J Clin Virol 2022; 149: 105126.
26. Ujiie M, Tsuzuki S, Nakamoto T, Iwamoto N. Resurgence of respiratory syncytial virus infections during COVID-19 pandemic, Tokyo, Japan. Emerg Infect Dis 2021; 27: 2969-2970.
27. Cohen R, Ashman M, Taha M-K, Varon E, Angoulvant F, Levy C, et al. Pediatric Infectious Disease Group (GPIP) position paper on the immune debt of the COVID-19 pandemic in childhood, how can we fill the immunity gap? Infect Dis Now 2021; 51: 418-423.
28. Thindwa D, Li K, Cooper-Wootton D, Zheng Z, Pitzer VE, Weinberger DM. Global patterns of rebound to normal RSV dynamics following COVID-19 suppression. BMC Infect Dis 2024; 24: 635.
29. Abu-Raya B, Viñeta Paramo M, Reicherz F, Lavoie P. Why has the epidemiology of RSV changed during the COVID-19 pandemic? EClinicalMedicine 2023; 61: 102089.
30. Cantú-Flores K, Rivera-Alfaro G, Muñoz-Escalante JC, Noyola DE. Global distribution of respiratory syncytial virus A and B infections: a systematic review. Pathog Glob Health 2022; 116: 398-409.
31. Salimi V, Tavakoli-Yaraki M, Yavarian J, Bont L, Mokhtari-Azad T. Prevalence of human respiratory syncytial virus circulating in Iran. J Infect Public Health 2016; 9: 125-135.
32. Korsun N, Trifonova I, Madzharova I, Alexiev I, Uzunova I, Ivanov I, et al. Resurgence of respiratory syncytial virus with dominance of RSV-B during the 2022–2023 season. Front Microbiol 2024; 15: 1376389.
33. Bhardwaj S, Choudhary ML, Chadha MS, Kinikar A, Bavdekar A, Gujar N, et al. Resurgence of respiratory syncytial virus infection during COVID-19 pandemic in Pune, India. BMC Infect Dis 2024; 24: 586.
34. Madi N, Safar HA, Al-Adwani A, Sadeq M, Al-Turab M. Genomic characterization of circulating human respiratory syncytial viruses A and B in Kuwait using whole-genome sequencing. Microbiol Spectr 2024; 12(7): e0015924.
35. Tayachew A, Mekuria Z, Shure W, Arimide DA, Gebeyehu A, Berkesa T, et al. Epidemiology of respiratory syncytial virus and its subtypes among cases of influenza like illness and severe acute respiratory infection: findings from nationwide sentinel surveillance in Ethiopia. BMC Infect Dis 2025; 25: 941.
36. Rios-Guzman E, Simons LM, Dean TJ, Agnes F, Pawlowski A, Alisoltanidehkordi A, et al. Deviations in RSV epidemiological patterns and population structures in the United States following the COVID-19 pandemic. Nat Commun 2024; 15: 3374.
37. Pierangeli A, Midulla F, Piralla A, Ferrari G, Nenna R, Pitrolo AMG, et al. Sequence analysis of respiratory syncytial virus cases reveals a novel subgroup-B strain circulating in north-central Italy after pandemic restrictions. J Clin Virol 2024; 173: 105681.
38. de Jesus-Cornejo J, Hechanova-Cruz RAB, Sornillo JBT, Okamoto M, Oshitani H; Viral Etiology Working Group. Prolonged RSV circulation in 2022 to 2023 associated with the emergence of a novel RSV-B clade in Biliran, Philippines. J Infect 2025; 90: 106467.
39. Huang L, Xu Y, Yang Y, Dong H, Luo Q, Chen Z, et al. Molecular epidemiology and clinical characteristics of respiratory syncytial virus in hospitalized children during winter 2021–2022 in Bengbu, China. Front Public Health 2024; 11: 1310293.
40. Wildenbeest JG, Billard M-N, Zuurbier RP, Korsten K, Langedijk AC, van de Ven PM, et al. The burden of RSV in healthy term-born infants in Europe: a prospective birth cohort study. Lancet Respir Med 2023; 11: 341-353.
41. Patton ME, Moline HL, Whitaker M, Tannis A, Pham H, Toepfer AP, et al. Interim Evaluation of Respiratory Syncytial Virus Hospitalization Rates Among Infants and Young Children After Introduction of Respiratory Syncytial Virus Prevention Products—United States, October 2024–February 2025. MMWR Morb Mortal Wkly Rep 2025; 74: 273-281.
42. Laham FR, Mansbach JM, Piedra PA, Hasegawa K, Sullivan AF, Espinola JA, et al. Clinical profiles of respiratory syncytial virus subtypes A and B among children hospitalized with bronchiolitis. Pediatr Infect Dis J 2017; 36: 808-810.
43. Bechini A, Salvati C, Bonito B, Del Riccio M, Stancanelli E, Bruschi M, et al. Costs and healthcare utilisation due to respiratory syncytial virus disease in paediatric patients in Italy: A systematic review. Public Health 2024; 227: 103-111.
| Files | ||
| Issue | Vol 18 No 3 (2026) | |
| Section | Original Article(s) | |
| DOI | https://doi.org/10.18502/ijm.v18i3.21663 | |
| Keywords | ||
| Respiratory syncytial virus Prevalence Respiratory infections Epidemiology | ||
| Rights and permissions | |
|
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
How to Cite
1.
Tavakoli F, Moghim S, Salimi V, Pourmirzaiee MA. Epidemiology and subtype analysis of respiratory syncytial virus among hospitalized children under five in Isfahan during early 2024. Iran J Microbiol. 2026;18(3):367-374.
