Table 2. Susceptibility of influenza A(H3N2) viruses detected in outbreaks, Yokohama, Japan, December 2018 (n = 4).

Isolate name	PA substitution	IC50, nM
		Baloxavir	Neuraminidase inhibitors (WHO criteria)
			Oseltamivira	Peramivira	Zanamivira	Laninamivira
A/YOKOHAMA/133/2018	I38T	227.08	0.41 (NI)	0.16 (NI)	0.88 (NI)	0.76 (NI)
A/YOKOHAMA/135/2018	I38T	144.02	0.25 (NI)	0.15 (NI)	0.81 (NI)	0.92 (NI)
A/YOKOHAMA/136/2018	38I	2.78	0.38 (NI)	0.12 (NI)	0.77 (NI)	1.05 (NI)
A/YOKOHAMA/134/2018	38I	1.02	0.28 (NI)	0.12 (NI)	0.76 (NI)	0.88 (NI)

PA: polymerase acidic subunit; IC₅₀: 50% inhibitory concentration; NI: Normal inhibition; WHO: World Health Organization.

^aThe median IC₅₀ values of 30 influenza A(H3N2) viruses isolated in the 2018/19 influenza season in Japan to oseltamivir, peramivir, zanamivir and laninamivir were 0.22 ± 0.08, 0.11 ± 0.02, 0.50 ± 0.26 and 0.98 ± 0.26, respectively.