Antiviral resistance surveillance in Japan (as of January 24, 2025)

Influenza surveillance is conducted as a part of the National Epidemiological Surveillance of Infectious Diseases (NESID) by the Ministry of Health, Labor, and Welfare, Japan.

Clinical specimens and the corresponding patient records are collected in 500 sentinel sites for laboratory-based surveillance. Public Health Institutes isolate influenza viruses from the specimens. Approximately 10-15% of total isolates are randomly selected and sent to the National Institute of Infectious Diseases (NIID). NIID analyze all viruses sent by the Public Health Institutes.

To monitor antiviral-resistant influenza viruses, we test A(H1N1)pdm09, A(H3N2) and B viruses by a combination of phenotypic and genotypic assays.In the phenotypic assay, viruses are subjected to a neuraminidase (NA) inhibition assay for NA inhibitors, oseltamivir, peramivir, zanamivir, and laninamivir, or a focus reduction assay for baloxavir.In the genotypic assay, allele-specific TaqMan RT-PCR and/or sequencing of NA, PA, and M2 genes were performed to detect antiviral resistance mutations. 

The data summarized below are results of phenotypic and genotypic assays reported.

2024/2025 influenza season (Sep. 2024-Aug. 2025)(as of December 25, 2024) NEW

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：17KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：22KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：22KB）

2023/2024 influenza season (Sep. 2023-Aug. 2024)(as of January 24, 2025) NEW 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：18KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：26KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：35KB）

2022/2023 influenza season (Sep. 2022-Aug. 2023)(as of November 11, 2024) 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：18KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：24KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：35KB）

2021/2022 influenza season (Sep. 2021-Aug. 2022)(as of February 2, 2023) 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：81KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：76KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：78KB）

2020/2021 influenza season (Sep. 2020-Aug. 2021)(as of July 27, 2021) 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：82KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：78KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：78KB）

2019/2020 influenza season (Sep. 2019-Aug. 2020)(as of August 18, 2021)

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：118KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：92KB） （PDF：61KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：81KB）

2018/2019 influenza season (Sep. 2018-Aug. 2019)(as of December 27, 2019) 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：61KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：60KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：48KB）

2017/2018 influenza season (Sep. 2017-Aug. 2018)(as of September 24, 2019)  

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：61KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：61KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：47KB）

2016/2017 influenza season (Sep. 2016-Aug. 2017)(as of January 27, 2020)

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：59KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：49KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：45KB）

2015/2016 influenza season (Sep. 2015-Aug. 2016)(as of January 27, 2020) 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（PDF：59KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（PDF：58KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（PDF：46KB）

2014/2015 influenza season (Sep. 2014-Aug. 2015)(as of March 4, 2016)  

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week

2013/2014 influenza season (Sep. 2013-Aug. 2014)(as of April 23, 2015)

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week

2012/2013 influenza season (Sep. 2012-Aug. 2013)(as of March 10, 2014)

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（GIF：26KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（GIF：69KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（GIF：67KB）

2011/2012 influenza season (Sep. 2011-Aug. 2012)(as of April 11, 2013) 

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（GIF：25KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（GIF：72KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（GIF：66KB）

2010/2011 influenza season (Sep. 2010-Aug. 2011)(as of February 6, 2013)

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（GIF：30KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（GIF：33KB）
• Table 3. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by week（GIF：25KB）

2009/2010 influenza season (Sep. 2009-Aug. 2010)(as of February 6, 2013)

• Table 1. Detection of antiviral drug-resistant viruses in Japan, [A(H1N1)pdm09, A(H3N2), B]（GIF：43KB）
• Table 2. Detection of A(H1N1)pdm09 viruses with H275Y mutation in Japan, Report by prefecture（GIF：120KB）

Laboratory of influenza virus surveillance and WHO Collaborating Center 
for Reference and Research on Influenza, Tokyo, Japan 
at Research Center for Influenza and Respiratory Viruses, 
National Institute of Infectious Diseases and
the Influenza Virus Surveillance Group of Japan

Go to Flash report of influenza virus in Japan（GIF：28KB）