Association of severe abnormal behavior of influenza patients and administered anti-influenza virus drugs: 2006-2022.

OBJECTIVES

Since February 2007, abnormal behaviors of influenza patients, especially of 10-19-year-olds, have raised public health concern in Japan. Those behavior-related events were caused putatively by anti-influenza drugs. The Ministry of Health, Labour and Welfare (MHLW) issued an administrative note to deter antiviral drug administration to 10-19-year-old patients, later withdrawing it on August 21, 2018, after detailed epidemiological study. The objective of this study using all reported data of abnormal behaviors from the 2006/2007 season through the 2021/2022 season in Japan was to evaluate the association of abnormal behavior types with anti-influenza virus drugs.

METHODS

MHLW had requested that all physicians report influenza cases with associated abnormal behaviors from the 2006/2007 season through the 2021/2022 season by abnormal behavior type: running, jumping from high places, sudden cessation of communication, being spooked or panicked, hallucination, and others. Differences in incidence rates among patients administered anti-influenza virus drugs were tested using Fisher's exact test.

RESULTS

Findings common to both age classes were that peramivir presented higher incident than oseltamivir for running, and that zanamivir or laninamivir presented higher incident for running and for jumping from high places. Peramivir presented a higher incident than either oseltamivir or zanamivir for abnormal behaviors of other types among 0-9-year-olds, but not among 10-19 year olds. Because patients with peramivir were presumed to have a more severe condition of influenza clinically, this result might suggest some association among the clinical condition and abnormal behaviors.

CONCLUSION

Findings indicate that oseltamivir alone does not raise risks of abnormal behavior among influenza patients.