The information is based on testing of influenza virus isolates obtained from cell culture, except for influenza A(H1) viruses for which genotypic assay is also performed on selected clinical specimens, and intends to provide a profile on the proportion of strains with reduced antiviral susceptibility. The date refers to specimen reception by the laboratory. Numbers and trends presented here should be interpreted in light of the small specimen numbers in particular categories.
Antiviral susceptibility testing of influenza A subtype H1 viruses in 2025
| Month | Phenotypic assay | Oseltamivir - Reduced susceptibility | Genotypic assay | H275Y substitution | ||
|---|---|---|---|---|---|---|
| No. | % | No. | % | |||
| Jan | 21 | 0 | 0% | - | - | - |
| Feb | 18 | 0 | 0% | - | - | - |
| Mar | 18 | 1 | 6% | - | - | - |
| Apr | 9 | 1 | 11% | - | - | - |
| May | 11 | 0 | 0% | - | - | - |
| Jun | 17 | 1 | 6% | - | - | - |
| Jul | 16 | 0 | 0% | - | - | - |
| Aug | 8 | 0 | 0% | - | - | - |
| Sep | 6 | 0 | 0% | 90 | 0 | 0% |
| Oct | 7 | 1 | 14% | 90 | 0 | 0% |
| Nov | ||||||
| Dec | ||||||
Antiviral susceptibility testing of influenza A subtype H3 viruses in 2025
| Month | Oseltamivir tested | Oseltamivir - Reduced susceptibility | |
|---|---|---|---|
| No. | % | ||
| Jan | 1 | 0 | 0% |
| Feb | 3 | 0 | 0% |
| Mar | 2 | 0 | 0% |
| Apr | 3 | 0 | 0% |
| May | 5 | 0 | 0% |
| Jun | 4 | 0 | 0% |
| Jul | 6 | 0 | 0% |
| Aug | 7 | 0 | 0% |
| Sep | 22 | 0 | 0% |
| Oct | 27 | 0 | 0% |
| Nov | |||
| Dec | |||
Antiviral susceptibility testing of influenza B viruses in 2025
| Month | Oseltamivir tested | Oseltamivir - Reduced susceptibility | |
|---|---|---|---|
| No. | % | ||
| Jan | 1 | 0 | 0% |
| Feb | 2 | 0 | 0% |
| Mar | 4 | 0 | 0% |
| Apr | 8 | 0 | 0% |
| May | 6 | 0 | 0% |
| Jun | 3 | 0 | 0% |
| Jul | 3 | 0 | 0% |
| Aug | 3 | 0 | 0% |
| Sep | 1 | 0 | 0% |
| Oct | 1 | 0 | 0% |
| Nov | |||
| Dec | |||