2.1 Patients
This study enrolled patients older than 15 years of age who were
diagnosed with influenza and required hospitalization between November
2014 and August 2019. Formal and collaborating members of the JRS
throughout the country were invited to participate in the study. The
members logged into the internet-surveillance system 3and registered the patients’ data. The required data included age, sex,
medical professional or not, presence of family transmission, diagnostic
methods, type of influenza, the onset date, the hospitalized date,
vaccination history for both influenza and pneumococcus, underlying
diseases or comorbidity, smoking habits, presence of obesity (body mass
index≥30), reasons for hospitalization, presence of pneumonia, category
and types of pneumonia, causative pathogens of pneumonia, antiviral
drugs used, presence of oxygen therapy or artificial ventilation,
antimicrobials used, and outcomes. The system sent reminder mails 14,
30, and 90 days after registration to follow up on the original
registration. The internet surveillance committee of the JRS extracted
and analyzed the registered data twice a year.
This study was registered with UMIN (UMIN000015989) and was approved by
all participating institutional review boards. All patients gave their
informed consents by being given opportunities to refuse to participate.