Clinical effectiveness of four neuraminidase inhibitors (oseltamivir, zanamivir, laninamivir, and peramivir) for children with influenza A and B in the 2014-2015 to 2016-2017 influenza seasons in Japan.

The clinical effectiveness of four neuraminidase inhibitors (NAIs) (oseltamivir, zanamivir, laninamivir, and peramivir) for children aged 0 months to 18 years with influenza A and B were investigated in the 2014-2015 to 2016-2017 influenza seasons in Japan. A total of 1207 patients (747 with influenza A and 460 with influenza B) were enrolled. The Cox proportional-hazards model using all of the patients showed that the duration of fever after administration of the first dose of the NAI was shorter in older patients (hazard ratio = 1.06 per 1 year of age, p < 0.001) and that the duration of fever after administration of the first dose of the NAI was shorter in patients with influenza A infection than in patients with influenza B infection (hazard ratio = 2.21, p < 0.001). A logistic regression model showed that the number of biphasic fever episodes was 2.99-times greater for influenza B-infected patients than for influenza A-infected patients (p < 0.001). The number of biphasic fever episodes in influenza A- or B-infected patients aged 0-4 years was 2.89-times greater than that in patients aged 10-18 years (p = 0.010), and the number of episodes in influenza A- or B-infected patients aged 5-9 years was 2.13-times greater than that in patients aged 10-18 years (p = 0.012).

Influenza-associated acute encephalopathy in Japanese children in 1994-2002.

We addressed the incidence of influenza-associated acute encephalopathy, which is distinct from Reye syndrome, in children in Japan. Eighty-nine children with a mean age of 3.8 years were reported to have developed this disease during eight influenza seasons (December 1994-April 2002) in Hokkaido, Japan. None of them had received aspirin. Most of the patients rapidly became comatose with or without convulsions with a mean interval of 1.7 days from the onset of fever to the onset of central nervous system symptoms. Thirty-three (37.1%) patients died and 17 (19.1%) patients had neurological sequelae. A total of 53 (59.6%) cases were proved to have an influenza virus infection. Interleukin-6 and tumor necrosis factor-alpha were markedly elevated in serum and cerebrospinal fluid samples from two patients who died after a rapid, fulminant course. A post-mortem examination of one fatal case revealed vasogenic brain edema with generalized vasculopathy, suggesting that the generalized impairment of vascular endothelial cells caused by highly activated cytokines plays a central role in the pathophysiology of this disease. We conclude that influenza-associated acute encephalopathy may be an underestimated syndrome and is another reason to promote vaccination against influenza in infants and younger children.