Respiratory syncytial virus (RSV) in infants hospitalized for acute lower respiratory tract disease: incidence and associated risks

Abstract

Respiratory syncytial virus (RSV) is one of the main causes of acute lower respiratory tract infections worldwide. We examined the incidence and associated risks for RSV infection in infants hospitalized in two university hospitals in the state of São Paulo. We made a prospective cohort study involving 152 infants hospitalized for acute lower respiratory tract infections (ALRTI) in two university hospitals in Campinas, São Paulo, Brazil, between April and September 2004. Clinical and epidemiological data were obtained at admission. RSV was detected by direct immunofluorescence of nasopharyngeal secretions. Factors associated with RSV infection were assessed by calculating the relative risk (RR). The incidence of RSV infection was 17.5%. Risk factors associated with infection were: gestational age less than 35 weeks (RR: 4.17; 95% confidence interval (CI) 2.21-7.87); birth weight less than or equal to 2,500 grams (RR: 2.69; 95% CI 1.34-5.37); mother's educational level less than five years of schooling (RR: 2.28; 95% CI 1.13-4.59) and pulse oximetry at admission to hospital lower than 90% (RR: 2.19; 95% CI 1.10-4.37). Low birth weight and prematurity are factors associated with respiratory disease due to RSV in infants. Low educational level of the mother and poor socioeconomic conditions also constitute risk factors. Hypoxemia in RSV infections at admission indicates potential severity and a need for early oxygen therapy.

Surveillance of eight respiratory viruses in clinical samples of pediatric patients in Southeast Brazil

“…Nos surtos epidêmicos de VRSH foi observado um padrão dependente da temperatura e nenhuma associação com precipitação pluviométrica, com picos nos meses mais frios do ano. Esse padrão dos surtos de VRSH é semelhante àquele observado por outros autores 18,19 …”

Comparison of direct immunofluorescence, conventional cell culture and polymerase chain reaction techniques for detecting respiratory syncytial virus in nasopharyngeal aspirates from infants

“…Immunofluorescence (IF), on the other hand, is widely used to detect RSV in epithelial nasopharyngeal cells because it is faster and less laborious than isolation. However, the IF technique requires a sample rich in cells, expertise in handling an immunofluorescence microscope 10 and is less sensitive than RT-PCR 18,20,22 . Our in house RT PCR could detect as few as 100 RSV copies, and this analytic sensitivity is similar to RT assays used in other studies 16 .…”

“…The respiratory syncytial virus (RSV) is considered to be the most common viral agent of lower respiratory tract infections in infants and young children, and can cause serious respiratory illnesses 5,7,12,20 .The highest morbidity rates are observed in infants, in the elderly and in the immunocompromised 4,9,17,18,22 . Viral isolation in cell cultures continues to be considered the most definitive test for diagnosis 6 .…”

A systematic review of predictive modeling for bronchiolitis

“…This model achieved a low AUC of 66%, a sensitivity of 80%, a low specificity of 68%, a positive predictive value of 82%, and a low negative predictive value of 66%. For infants hospitalized for acute lower respiratory tract disease, Riccetto et al [126] identified several risk factors for RSV infection: gestational age < 35 weeks, birth weight ≤ 2.5 kg, mother has less than five years of school education, and pulse oximetry < 90% upon hospital admission time.…”