title: Very low pandemic influenza A (H1N1) 2009 mortality associated with early neuraminidase inhibitor treatment in Japan: analysis of 1000 hospitalized children.
abstract: OBJECTIVE
  There were many cases of pandemic influenza A (H1N1) 2009 (H1N1/09) in Japan during the 2009-2010 epidemic. They accounted for 16% of the total population (20.7 million/128 million), and 59% of the patients were children 15 years of age and under (12.2 million/20.7million). However, there were only 38 paediatric deaths. We analyzed the clinical manifestations and treatment of children hospitalized because of H1N1/09 infection in order to clarify the association between treatment with neuraminidase inhibitors and the low mortality rate.
  
  
  METHODS
  A retrospective chart review was performed on a total of 1000 paediatric inpatients.
  
  
  RESULTS
  The causes of the hospitalizations were respiratory complications in 651 cases (65.1%), neurological complications in 255 cases (25.5%) and other complications in 94 cases. Neuraminidase inhibitors, primarily oseltamivir, had been used to treat 984 (98.4%) of the 1000 patients, and in 88.9% of the patients, treatment with neuraminidase inhibitors was initiated within 48 h after the onset of illness. Only 12 (1.2%) of the 1000 patients underwent mechanical ventilation, and one patient died of H1N1/09 infection.
  
  
  CONCLUSIONS
  Although a high proportion of the patients in this study had severe respiratory complications, the case fatality rate was only 0.1%. The low mortality rate of children due to the H1N1/09 epidemic in Japan was probably attributable to the universal implementation of early treatment with neuraminidase inhibitors.
authors: Department of Paediatrics, Keiyu Hospital, 3-7-3 Minatomirai, Nishi-ku, Yokohama, 220-0012 Kanagawa, Japan. sugaya-n@za2.so-net.ne.jp
authors: Norio
authors: N
authors: Sugaya
authors: Masayoshi
authors: M
authors: Shinjoh
authors: Keiko
authors: K
authors: Mitamura
authors: Takao
authors: T
authors: Takahashi
mesh_terms: D000293:Adolescent; D000998:Antiviral Agents / Q000008:administration & dosage* / Q000494:pharmacology; D002648:Child; D002673:Child, Hospitalized; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects / Q000302:isolation & purification*; D007251:Influenza, Human / Q000188:drug therapy* / Q000401:mortality* / Q000821:virology; D007564:Japan; D008297:Male; D009439:Neuraminidase / Q000037:antagonists & inhibitors; D053139:Oseltamivir / Q000008:administration & dosage* / Q000494:pharmacology; D012189:Retrospective Studies; D013997:Time Factors; D014764:Viral Proteins / Q000037:antagonists & inhibitors; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D014764:Viral Proteins; D053139:Oseltamivir; C487630:NA protein, influenza A virus; D009439:Neuraminidase