Report of the National Influenza Surveillance Scheme, 2020–2021
DOI:
https://doi.org/10.33321/cdi.2026.50.021Keywords:
influenza, surveillance, influenza-like illness, sentinel surveillanceAbstract
This report describes influenza surveillance activities in Australia in 2020 to 2021 and the impact which coronavirus disease 2019 (COVID-19) related public health and social measures (PHSMs) had on influenza notifications. Data were extracted from several sources constituting the National Influenza Surveillance Scheme.
In 2020 and 2021, a range of PHSMs were instituted across Australia to reduce the spread of COVID-19. These measures had a substantial impact on influenza circulation during this time. Laboratory-confirmed influenza notifications in these years were the lowest reported to the National Notifiable Diseases Surveillance System (NNDSS) since influenza became nationally notifiable in 2001. Laboratory-confirmed influenza notification rates varied greatly between states and territories in the two-year reporting period, likely influenced by differences in the PHSMs instituted across the country. Higher influenza notification rates were observed in the 0–4 and 5–9 year age groups in 2020, while the notification rates in 2021 were very low across all age groups. In 2020, eighty-seven percent of laboratory-confirmed influenza notifications were influenza A (91.1% influenza A(unsubtyped); 7.7% A(H1N1)pdm09; 1.2% A(H3N2)) and 12.6% were influenza B. In 2021, seventy-two percent of laboratory-confirmed influenza notifications were influenza A (91.1% influenza A(unsubtyped); 8.3% A(H3N2); 1.3% A(H1N1)pdm09) and 17.3% were influenza B.
Very low influenza activity was also observed in community sentinel surveillance systems. However, slight increases in influenza-like illness, still at very low rates compared to previous years, were reported by sentinel general practices, with rises observed in mid-June in both 2020 and 2021. Very few laboratory-confirmed influenza sentinel hospital admissions and deaths were reported in 2020 and 2021.
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