Epidemiology and virology of acute respiratory infections during the first year of life: a birth cohort study in Vietnam

Journal article

Understanding viral etiology and age-specific incidence of acute respiratory infections in infants can help identify risk groups and inform vaccine delivery, but community-based data is lacking from tropical settings.One thousand four hundred and seventy-eight infants in urban Ho Chi Minh City and 981 infants in a semi-rural district in southern Vietnam were enrolled at birth and followed to 1 year of age. Acute respiratory infection (ARI) episodes were identified through clinic-based illness surveillance, hospital admissions and self-reports. Nasopharyngeal swabs were collected from infants with respiratory symptoms and tested for 14 respiratory pathogens using multiplex reverse transcription-polymerase chain reaction.Estimated incidence of ARI was 542 and 2691 per 1000 infant-years, and hospitalization rates for ARI were 81 and 138 per 1000 infant-years, in urban and semi-rural cohorts, respectively, from clinic- and hospital-based surveillance. However self-reported ARI episodes were just 1.5-fold higher in the semi-rural versus urban cohort, indicating that part of the urban-rural difference was explained by under-ascertainment in the urban cohort. Incidence was higher in infants ≥6 months of age than <6 months, but this was pathogen-specific. One or more viruses were detected in 53% (urban) and 64% (semi-rural) of samples from outpatients with ARI and in 78% and 66% of samples from hospitalized ARI patients, respectively. The most frequently detected viruses were rhinovirus, respiratory syncytial virus, influenza virus A and bocavirus. ARI-associated hospitalizations were associated with longer stays and more frequent ICU admission than other infections.ARI is a significant cause of morbidity in Vietnamese infants and influenza virus A is an under-appreciated cause of vaccine-preventable disease and hospitalizations in this tropical setting. Public health strategies to reduce infant ARI incidence and hospitalization rates are needed.

Authors: Anders, K; Nguyen, H; Nguyen, N; Van Thuy, N; Hong Van, N

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Lippincott, Williams & Wilkins
• Journal: Pediatric Infectious Disease Journal
• Volume: 34
• Issue: 4
• Pages: 361–370
• Publication date: 2015-04-01
• DOI: 10.1097/INF.0000000000000643
• ISSN: 0891-3668, 1532-0987
• Pmid: 25674708
• Language: English
• Keywords: viruses; young adult; reverse transcriptase polymerase chain reaction; Vietnam; respiratory tract infections; pregnancy; adult; incidence; multiplex polymerase chain reaction; cohort studies; male; virus diseases; humans; female; nasopharynx; infant; respiratory syncytial viruses; infant, newborn; SBTMR