Table 2.
| Year | Actual impact of season | Parametersa | Total score (max=20) | Severity indexb, % | ||||
| Timing of seasonal onset (score) | Relative magnitude of influenza activity (score) | Dominant strain (score) | Vaccine mismatch in the season (score) | Early season deaths (score) | ||||
| 2007 | Severe | 1.1 (1) | 1.3 (1) | A/H3N2 (3) | All strains (4) | 18c (3) | 12 | 60 |
| 2008 | Moderate | 1.7 (2) | 2.8 (4) | B (1) | 1 strain (2) | 3c (1) | 10 | 50 |
| 2009 | Very severe (pandemic) | 13.7 (4) | 19.3 (4) | Novel/pandemic strain or A/H1N1pdm09 (4) | All strains (4) | 61 (4) | 20 | 100 |
| 2010 | Mild | 1.2 (1) | 0.3 (0) | A/H1N1pdm09 (2) | None (1) | 2 (1) | 5 | 25 |
| 2011 | Moderate | 1.1 (1) | 1.4 (1) | A/H1N1pdm09 (2) | None (1) | 10 (2) | 7 | 35 |
| 2012 | Severe | 2.5 (3) | 1.4 (1) | A/H3N2 (3) | >1 but not all strains (3) | 23 (3) | 13 | 65 |
| 2013 | Moderate | 1.1 (1) | 0.8 (0) | A/H1N1pdm09 (2) | 1 strain (2) | 11 (2) | 7 | 35 |
| 2014 | Moderate | 1.1 (1) | 1.2 (1) | A/H1N1pdm09 (2) | 1 strain (2) | 22 (3) | 9 | 45 |
| 2015 | Moderate | 1.5 (1) | 2.9 (4) | B (1) | None (1) | 46 (4) | 11 | 55 |
| 2016 | Moderate | 1.0 (0) | 1.5 (1) | A/H1N1pdm09 (2) | None (1) | 17 (3) | 7 | 35 |
| 2017 | Severe | 1.3 (1) | 2.1 (3) | A/H3N2 (3) | 1 strain (2) | 43 (4) | 13 | 65 |
| 2018d | Moderate | 0.6 (0) | 1.0 (0) | A/H1N1pdm09 (2) | None (1) | 35 (3) | 6 | 30 |
aTiming of seasonal onset: ratio of laboratory-confirmed influenza notifications in May/January to April average [5]; relative magnitude of influenza activity: ratio of laboratory-confirmed influenza notifications in May compared to last 5 years’ average [5]; dominant strain: dominant strain in circulation [7]; vaccine mismatch in season: vaccine mismatch with dominant strain(s) [7]; early season deaths: rate per 100,000 population of notified influenza-associated deaths at the end of July in the season [7].
cSeverity index=total score/maximum score.
dInfluenza-associated deaths in 2007 and 2008 were estimated by calculating the proportion (total number of notifications at the end of July/total notifications in the year) multiplied by total deaths reported by the Australian Bureau of Statistics for 2007 and 2008, accordingly.
eProspective year, real-time data.