A community cluster of influenza A(H3N2) virus infection with reduced susceptibility to baloxavir due to a PA E199G substitution in Japan, February to March 2023

• Published in: Euro surveillance : bulletin européen sur les maladies transmissibles Vol. 28; no. 39; p. 1
• Main Authors: Takashita, Emi, Fujisaki, Seiichiro, Morita, Hiroko, Nagata, Shiho, Miura, Hideka, Matsuura, Yuki, Yamamoto, Saya, Chiba, Shoko, Inoue, Yumiko, Minami, Iori, Yoshikawa, Sayaka, Yamazaki, Seiko, Kishida, Noriko, Nakamura, Kazuya, Shirakura, Masayuki, Watanabe, Shinji, Hasegawa, Hideki
• Format: Journal Article
• Language: English
• Published: Saint-Maurice Centre Europeen pour la Surveillance Epidemiologique du SIDA (European Centre for the Epidemiological Monitoring of AIDS) 28-09-2023; European Centre for Disease Prevention and Control (ECDC)
• Subjects: Antiviral drugs; Health surveillance; Influenza; Rapid Communication; Viruses; Japan
• ISSN: 1560-7917; 1025-496X; 1560-7917
• DOI: 10.2807/1560-7917.ES.2023.28.39.2300501

A community cluster of influenza A(H3N2) caused by viruses with an E199G substitution in PA was detected in Nara, Japan, between February and March 2023. The three patients with these mutant viruses had not received antiviral treatment before specimen collection but patients in the same hospital had. The sequences of the mutant viruses were closely related, suggesting clonal spread in Nara. They showed reduced susceptibility to baloxavir in vitro; however, the clinical significance of the PA E199G substitution remains unclear.