Table 1.
Virus and patient characteristics for influenza type A viruses (n = 138) phenotypically tested by WHO CCs and showing reduced (RI) or highly reduced inhibition (HRI) by NAIs.a
| Virus (n) | n | IC50 fold-change compared to reference median IC50 valuesb | NA substitutionc | Patient setting | Antiviral treatment | Immunocompromised | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Oseltamivir | Zanamivir | Peramivir | Laninamivir | Virus isolate | Clinical specimen | |||||
| A(H1N1) pdm09 (133 of 10280) | 101 | 286–2194 | 0.5–3 | 86–629 (75) | 1–5 (75) | H275Y | Not availabled (30) H275Y (65) H275Y/H mix (6) |
Community (42) Hospital (43) Unknown (16) |
Yes, oseltamivir (20) Yes, peramivir (5) Yes, laninamivir (1) Yes, oseltamivir, baloxavir (1) Yes, peramivir, laninamivir (1) Yes, oseltamivir, laninamivir (3) No (29) Unknown (41) |
Yes (5) No (62) Unknown (34) |
| 6 | 24–976 | 1–4 (4) | 32–197 (2) | 3 (2) | H275Y/H mix | Not available (3) H275Y/H mix (2) Nonee (1) |
Community (1) Hospital (2) Unknown (3) |
No (1) Unknown (5) |
No (3) Unknown (3) |
|
| 1 | 1376 | 3 | 746 | 3 | G147R/G mix, H275Y | Not available | Unknown | Unknown | Unknown | |
| 10 | 0.5–2 (8) | 13–332 | 15–196 (5) | 5–56 (5) | Q136K (5) Q136K/Q mix, D151E/D mix (2) Q136K/Q mix, D151N/D mix (1) Q136R (2) |
Not available (8) None (2) |
Hospital (4) Unknown (5) Community (1) |
Unknown (9) No (1) |
Unknown (8) No (2) |
|
| 6 | 11–28 | 2–8 | 1–11 (5) | 1–5 (5) | I223K (3) I223L (1) I223M (1) I223R (1) |
I223K (2) I223L (1) I223M (1) Not available (2) |
Unknown (6) | Unknown (6) | Unknown (6) | |
| 3 | 96–191 | 3–4 | 2–13 (2) | 3–4 (2) | N295S | Not available (1) N295S (2) |
Unknown (2) Hospital (1) |
Unknown (2) Yes (1) |
Unknown (3) | |
| 2 | 1–2 | 26–81 | 9–83 | 6–7 | E119K (1) E119K, Q136K (1) |
None | Hospital | Unknown | Unknown | |
| 1 | 11 | 11 | 1 | 2 | V116A | Not available | Unknown | Unknown | Unknown | |
| 1 | 1 | 321 | 24 | 58 | E119G | None | Hospital | Unknown | Unknown | |
| 1 | 52 | 21 | n/tf | n/t | R152K | Not available | Hospital | Unknown | Unknown | |
| 1 | 12 | 3 | 2 | 1 | D199G | None | Unknown | Unknown | Unknown | |
| A(H3N2) (5 of 7755) | 2 | 4.5–6 | 12–21 | 2 (1) | 4 (1) | D151N/D mix (1) D151N/D mix, V165I (1) |
Not available | Community (1) Sentinel outpatient (1) |
Unknown (1) No (1) |
Unknown (1) No (1) |
| 1 | 1 | 17 | n/t | n/t | M241 V/M mix | Not available | Unknown | Yes | Unknown | |
| 1 | 15 | 5 | 1.5 | 1 | N245Y(-gly) | N245Y(-gly) | Hospital | Yes, peramivir | Unknown | |
| 1 | 11.5 | 4 | 1 | 2 | S331R | S331R | Community | No | No | |
The number of viruses for which data were reported is shown in parentheses if it is less than the number in the ‘n’ column.
Reduced inhibition (RI) and highly reduced inhibition (HRI) fold-change values are displayed underlined and in bold typeface. For type A viruses, normal inhibition (NI) is a <10-fold increase in the NAI IC50; RI is a 10- to 100-fold increase; and HRI is a >100-fold increase (World Health Organization, 2012).
Amino acid position numbering is A subtype specific.
Clinical specimen not available for sequencing.
None: the sequence contained no amino acid substitutions when compared to the consensus sequence of viruses for the same subtype.
n/t: not tested.