Volume 25, Number 10—October 2019
Susceptibility of Influenza A, B, C, and D Viruses to Baloxavir1
|No. viruses tested||EC50, nmol/L, mean ± SD†||No. viruses tested||EC50, nmol/L, mean ± SD†|
|H5N6‡||3||0.31 ± 0.19||–||–|
|H7N9||19||0.48 ± 0.32||9||1.44 ± 1.08|
|H1N1¶||–||–||3||0.72 ± 0.27|
|H1N1v||–||–||3||0.51 ± 0.12|
|H1N2v||–||–||9||1.19 ± 0.36|
||0.86 ± 0.50
|A/Illinois/08/2018 (H1N1)pdm09 PA-I38||2.12||–||1.75 ± 0.59|
|A/Illinois/37/2018 (H1N1)pdm09 PA-I38L
||14.96 (7-fold)**||–||13.09 ± 3.56 (8-fold)**|
*Both assays were conducted by using MDCK-SIAT1 cells. Details on viruses tested are in the Appendix. According to World Health Organization nomenclature, the swine-origin influenza viruses isolated from humans are named variant viruses (e.g., A[H1N1]v). EC50, 50% effective concentration; FRA, focus reduction assay; HINT, high-content imaging neutralization test; –, not tested.
†Mean ± SD or average of 2 test results.
‡One of 3 viruses was isolated from chicken (Appendix Table 1).
§Virus was isolated from chicken (Appendix Table 1).
¶All 3 viruses were isolated from swine (Appendix Table 2).
#A pair of seasonal influenza A(H1N1)pdm09 viruses were included in each test as reference viruses (12).
**Fold change to EC50 of virus carrying PA-I38L compared with sequence-matched control virus carrying PA-I38.
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1Preliminary results from this study were presented at the 6th International Society for Influenza and Other Respiratory Virus Diseases Antiviral Group Conference; November 13–15, 2018; Rockville, Maryland, USA.