TABLE 2.
Zanamivir susceptibility of paired influenza virus clinical isolates from NAIB2008
Treatment group | Virus subtype | Subject | Sample day | Plaque reduction IC50 (μg/ml)a | NA IC50 (ng/ml)a |
---|---|---|---|---|---|
QID | H3N2 | 7222 | 1 | 0.04 ± 0.02 | C |
2 | 0.05 ± 0.06 | C | |||
H3N2 | 7232 | 1 | 0.04 ± 0.02 | 0.9 ± 0.57 | |
3 | 0.05 ± 0.06 | 1.65 ± 0.35 | |||
H3N2 | 7241 | 1 | >100 | C | |
4 | >100 | C | |||
H3N2 | 7228 | 1 | 0.04 ± 0.05 | 0.75 ± 0.35 | |
3 | 0.09 ± 0.05 | 0.95 ± 0.78 | |||
H3N2 | 7249 | 1 | >100 | 0.9 ± 0.14 | |
4 | >100 | 0.75 ± 0.21 | |||
H3N2 | 7257 | 1 | >100 | 0.4 ± 0.14 | |
2 | >100 | 3.1 ± 0.42 | |||
BID | H3N2 | 7227 | 1 | >100 | C |
2 | >100 | C | |||
H3N2 | 7244 | 1 | >100 | 0.8 ± 0.14 | |
2 | >100 | 0.6 ± 0.28 | |||
H3N2 | 7256 | 1 | >100 | 1.1 ± 0.28 | |
3 | >100 | 2.75 ± 1.63 | |||
H3N2 | 7230 | 1 | 0.22 ± 0.12 | C | |
2 | 50.29 ± 49.72b | C | |||
H3N2 | 7259 | 1 | NT | 0.8 ± 0.14 | |
3 | NT | 2.85 ± 2.05 | |||
H1N1 | 7239 | 1 | >100 | 10 ± 00 | |
2 | >100 | 0.95 ± 0.07 | |||
Placebo | H3N2 | 7229 | 1 | >100 | 0.945 ± 0.36 |
3 | >100 | 1.25 ± 0.35 | |||
H3N2 | 7237 | 1 | >100 | 1.35 ± 0.07 | |
3 | >100 | 1.4 ± 0.71 | |||
H3N2 | 7248 | 1 | NT | 1.05 ± 0.49 | |
4 | NT | 1.05 ± 0.35 | |||
H1N1 | 7231 | 1 | NT | 0.5 ± 0.42 | |
3 | NT | 0.5 ± 0.42 | |||
H1N1 | 7242 | 1 | >100 | 0.85 ± 0.35 | |
4 | >100 | 0.9 ± 0.28 | |||
H3N2 | 7250 | 1 | NT | 1.3 ± 0.57 | |
5 | NT | 0.9 ± 0.57 | |||
H3N2 | 7258 | 1 | NT | 1.2 ± 0.57 | |
3 | NT | 1.05 ± 0.35 | |||
Negative control | B/Beijing/1/87 | 0.012 | 14.3 | ||
Positive control | B/Beijing/ Zrc | >100 | 2,326 |
Values represent the means of at least two assays. C, insufficient NA activity following concentration; 76% of isolates were influenza A (H3N2); the remainder were influenza A (H1N1); NT, not tested.
One replicate had an IC50 of >100 μM.
Zanamivir-resistant influenza B/Beijing/1/87 (HA, Val105-Ala, Leu225-Gln; NA, Glu116-Gly).