Table 2. Influenza viruses submitted to the United States national surveillance and subjected to next generation sequencing analysis, 2016/17 and 2017/18 influenza seasons.
| Virus | Influenza Season | Total | |
|---|---|---|---|
| 2016/17 | 2017/18a | ||
| A(H3N2) | 1,594 | 1,570 | 3,164 |
| A(H1N1)pdm09 | 383 | 967 | 1,350 |
| B/Victoria | 459 | 304 | 763 |
| B/Yamagata | 660 | 954 | 1,614 |
| Totalb | 3,096 | 3,795 | 6,891 |
| Specimen only | 2,168 | 3,036 | 5,204 |
| Isolate only | 81 | 62 | 143 |
| Both specimen and isolate | 847 | 697 | 1,544 |
a Included in the analysis were 235 viruses, 185 A(H3N2) and 50 A(H1N1)pdm09, collected from 12 US states for enhanced antiviral surveillance.
b The total number of influenza viruses with polymerase acidic sequences downloaded from Global Initiative on Sharing All Influenza Data database; duplicate sequences were not counted.
Season 2016/17 dates are 1 October 2016–30 September 2017; season 2017/18 dates are 1 October 2017–30 September 2018.