What is it about?

In Japan, most people with cold symptoms see a doctor, are tested for influenza and, if positive, are prescribed antiviral medication in most cases. There are also six different medicines available for influenza. This type of practice is not common in other countries. Using a national Japanese medical database, we looked at who is prescribed which drugs and for which people. In Japan, with a population of 126 million, between 6.7 and 13.4 million people were prescribed antiviral drugs each year and between 21.1 and 32 million flu tests were performed; only 14,000 people were prescribed flu drugs in 2020 due to COVID-19. Influenza was the most common illness among children, accounting for 37.6% of all prescriptions. It is also a frightening disease for the elderly, leading to hospitalisation and death, with those aged 65 and over accounting for 12.2%. The higher number of female patients than male patients in their 30s may also reflect the fact that child care in Japan is biased towards mothers and that many kindergarten and primary school teachers are women. The newer drugs laninamivir and baloxavir, which require only one dose of oral or inhalation to complete treatment, were prescribed more frequently in Japan than oseltamivir and zanamivir, which have been used for many years and have extensive efficacy and safety data.

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Why is it important?

Influenza treatment in Japan is unique, but for the first time, large-scale data on the actual situation can be presented. Data on the number, gender and age of influenza patients have been collected for some time, but additional data on treatment, such as in this study, will hopefully help to evaluate and improve practice in Japan. There are regional differences in the choice of treatment, and it is also necessary to examine what doctors are basing their choice of treatment on, and whether practice guidelines are needed.


The database used in this study, NDB open data, does not contain detailed information, so future studies that delve deeper into the subject will be necessary.

Akahito Sako
Kohnodai Hospital, National Center for Global Health and Medicine

Read the Original

This page is a summary of: Prescription of anti-influenza drugs in Japan, 2014–2020: A retrospective study using open data from the national claims database, PLoS ONE, October 2023, PLOS,
DOI: 10.1371/journal.pone.0291673.
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