title: Clinical features of children hospitalized with influenza A and B infections during the 2012-2013 influenza season in Italy.
abstract: BACKGROUND
  Influenza is a major public health issue worldwide. It is characterized by episodes of infection that involve hundreds of millions of people each year. Since that in the seasons 2010-2011 and 2011-2012 the circulation of FLUB was decreasing we evaluated the clinical presentation, demographic characteristics, admitting department, and length of stay in children who contracted influenza admitted to Bambino Gesù Children's Hospital, during the 2012-2013 influenza season, with the aim to establish if the recover of FLUB was associated to a clinical worsening, in comparison with those due to FLUA.
  
  
  METHODS
  A total of 133 respiratory specimens, collected from patients with symptoms of respiratory tract infections, positive for the Influenza A and B viruses (FLUA and B) were subtyped. Comparisons between the FLUA and FLUB groups were performed with the one-way ANOVA for continuous parametric variables, the Mann-Whitney test for non-parametric variables, or the Chi-Square test or Fisher's exact test (if cells <5) for categorical variables.
  
  
  RESULTS
  87.09% of the FLUA isolates were the H1N1 subtype and 12.90% were H3N2. Among the FLUB isolates, 91.54% were the B/Yamagata/16/88 lineage and 8.45% were the B/Victoria/02/87 lineage. The largest number of FLUA/H1N1 cases was observed in children less than 1 years old, while the B/Yamagata/16/88 lineage was most prevalent in children 3-6 years old. Fever was a common symptom for both FLUA and B affected patients. However, respiratory symptoms were more prevalent in patients affected by FLUA. The median length of stay in the hospital was 5 days for FLUA and 3 days for FLUB.
  
  
  CONCLUSIONS
  The clinical features correlated to different Influenza viruses, and relevant subtypes, were evaluated concluding that the increasing of FLUB in the season 2012-2013 was without any dramatic change in clinical manifestation. Our findings suggest, finally, that a stronger commitment to managing patients affected by FLUA is required, as the disease is more severe than FLUB.
authors.affiliation: Virology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. liviamancinelli12@gmail.com.
authors.forename: Livia
authors.initials: L
authors.lastname: Mancinelli
authors.affiliation: Virology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. manuela.onori@libero.it.
authors.forename: Manuela
authors.initials: M
authors.lastname: Onori
authors.affiliation: Virology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. carlo.concato@opbg.net.
authors.forename: Carlo
authors.initials: C
authors.lastname: Concato
authors.affiliation: Laboratory of Biometry, University of Tor Vergata, Rome, Italy. sorge@uniroma2.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sorge
authors.affiliation: Virology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. stefano.chiavelli@opbg.net.
authors.forename: Stefano
authors.initials: S
authors.lastname: Chiavelli
authors.affiliation: Virology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. luana.coltella@opbg.net.
authors.forename: Luana
authors.initials: L
authors.lastname: Coltella
authors.affiliation: Pediatric Emergency Department, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. umberto.raucci@opbg.net.
authors.forename: Umberto
authors.initials: U
authors.lastname: Raucci
authors.affiliation: Pediatric Emergency Department, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. antonio.reale@opbg.net.
authors.forename: Antonio
authors.initials: A
authors.lastname: Reale
authors.affiliation: Medical Direction, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. donato.menichella@opbg.net.
authors.forename: Donato
authors.initials: D
authors.lastname: Menichella
authors.affiliation: Virology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy. cristina.russo@opbg.net.
authors.forename: Cristina
authors.initials: C
authors.lastname: Russo
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003710:Demography; D005260:Female; D005334:Fever; D006760:Hospitalization; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D007251:Influenza, Human / Q000503:physiopathology* / Q000821:virology; D007558:Italy; D007902:Length of Stay; D008297:Male; D012621:Seasons