Japanese Surveillance Systems and Treatment for Influenza

Influenza management and surveillance programs in Japan possess several unique features. The national influenza surveillance is affiliated with National Epidemiological Surveillance for Infectious Diseases (NESID) and features sentinel outpatient surveillance, virological surveillance, and reports on hospitalization, mortality, and influenza-associated encephalopathy. Of note, information on the number of student absences and class/grade/school closures due to influenza are also reported to the government and made publically available. A private online influenza surveillance portal by volunteer doctors provides a real-time information source for the Japanese clinicians and the general public. For influenza treatment, three classes of drugs are approved and covered by national medical insurance in Japan: M2 inhibitors, neuraminidase inhibitors (NAIs), and a polymerase inhibitor. Four NAIs, oseltamivir, zanamivir, laninamivir, and peramivir, are licensed in Japan and are prescribed to seven to eight million patients annually. NAIs are prescribed to any influenza outpatient rather than being limited to severe cases. The majority (80–95 %) of patients start the treatment within 48 h of onset. Laninamivir and peramivir were used almost solely in Japan, until the approval of the latter drug by the FDA. Observational studies showed that the two drugs have equal effectiveness as oseltamivir and zanamivir. The Japanese approach to influenza surveillance and management has facilitated bringing new influenza antivirals to the markets and has driven innovative research in this field. New classes of antivirals, including polymerase inhibitors and cap-dependent endonuclease inhibitor, provide novel tools for treatment of influenza in Japan and the rest of the world.