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. 2000 Jan;44(1):78–87. doi: 10.1128/aac.44.1.78-87.2000

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
a

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. 

b

One replicate had an IC50 of >100 μM. 

c

Zanamivir-resistant influenza B/Beijing/1/87 (HA, Val105-Ala, Leu225-Gln; NA, Glu116-Gly). 

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