title: Hospitalization for respiratory syncytial virus bronchiolitis and disease severity in twins.
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) is a common cause of lower respiratory tract disease and hospitalization in infants and young children. Infants of multiple births, who are often premature, might be more susceptible to developing a more severe RSV infection than singletons.
  
  
  OBJECTIVE
  To assess the impact of multiple births on the severity of RSV infection and define risk factors for acquiring RSV infection in infants of multiple birth.
  
  
  METHODS
  Clinical data on infants hospitalized with RSV infection between 2008 and 2010 were retrospectively collected.
  
  
  RESULTS
  Twins comprised 7.6% (66/875) of hospitalized infants with RSV bronchiolitis during the study period. Infants in the twin group were younger (122.4 +/- 131.7 vs. 204.5 +/- 278.8 days, P = 0.014), had a lower mean gestational age (35.3 +/- 2.6 vs. 38.6 +/- 2.5 weeks, P < 0.001), and were more likely to have been born prematurely compared with singleton infants (65.6% vs. 13%, P < 0.001). On a multivariable logistic regression analysis, young age, early gestational age and male gender were the only variables identified as risk factors for pediatric intensive care unit admission (P < 0.001, P < 0.001 and P = 0.03, respectively). In contrast, the mere fact of a child being a twin was not found to be a significant risk factor for disease severity. In addition, if one twin is hospitalized due to RSV infection, the other has a 34% chance of also being hospitalized with bronchiolitis. Young age was a significant risk factor for hospitalization of the second twin (P < 0.001) CONCLUSIONS: Our findings suggest that twins hospitalized with RSV bronchiolitis do not have an increased risk for severe infection as compared to singletons. However, a twin of an infant hospitalized with RSV infection has a considerable risk of also being hospitalized with bronchiolitis, thus close monitoring is recommended.
authors: Department of Pediatrics 1A, Schneider Children's Medical Center of Israel, Petah Tikva, Israel. miridotan@gmail.com
authors: Miri
authors: M
authors: Dotan
authors: Department of Pediatrics 2C, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors: Liat
authors: L
authors: Ashkenazi-Hoffnung
authors: Department of Microbiology, Rabin Medical Center (Beillinson Campus), Petah Tikva, Israel.
authors: Zmira
authors: Z
authors: Samra
authors: Department of Pediatrics 1A, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors: Gilat
authors: G
authors: Livni
authors: Department of Pediatrics 1A, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors: Havatzelet
authors: H
authors: Yarden-Bilavsky
authors: Department of Pediatrics 2C, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors: Jacob
authors: J
authors: Amir
authors: Department of Pediatrics 2C, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.
authors: Efraim
authors: E
authors: Bilavsky
mesh_terms: D000367:Age Factors; D001990:Bronchiolitis, Viral / Q000453:epidemiology / Q000503:physiopathology* / Q000821:virology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005865:Gestational Age; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology / Q000503:physiopathology*; D018113:Respiratory Syncytial Virus, Human / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D014427:Twins