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.
Background:As most Salmonella Typhi (S. Typhi) cases notified to public health units in Australia are acquired overseas, a case without recent travel raises concerns of local transmission. We describe a case of S. Typhi in a hospital inpatient without recent travel, where early use of genomic sequencing suggested remote acquisition from Chile in the 1980s, with chronic asymptomatic carriage. This facilitated the stand-down of a complex acquisition investigation. Case:A notification of S. Typhi on stool culture was received for a female aged over 90 years living in Melbourne, Australia in October 2023. She had been hospitalised for three weeks (unrelated illness) and transferred into a residential aged care facility (RACF) six days prior to the result being known. She was asymptomatic and the sample was collected due to a recent ward gastroenteritis outbreak. Investigation:Epidemiological investigation identified the case had emigrated to Australia in 1981 from Chile. Recent typhoid-like illness, overseas travel or contact with travellers from endemic areas were excluded. Subsequent genomic sequencing identified the isolate was multilocus sequence type 2 and did not cluster with any strains isolated in Victorian or international databases, most closely clustering with historical South American strains, with potential in-host changes over time. Management:The case was presumed infectious throughout their hospital stay, with chronic carriage. There were 18 contacts, of whom 14 provided screening samples and were negative. Antibiotic case clearance was not recommended by the treating clinician due to patient comorbidity, treatment toxicity risks and unlikely treatment success without gallbladder removal. Enhanced infection control measures were instituted in the RACF (e.g. private bathroom, contact precautions for personal care, no food preparation). No additional cases were reported after two incubation periods (60 days). Conclusion:Early genomic sequencing enhanced the efficiency of the public health investigation by rapidly confirming overseas acquisition and chronic carriage, obviating the need for extensive local upstream investigation.
Two incursions of high pathogenicity avian influenza (HPAI) A(H5N1) clade 2.3.4.4b in vagrant birds were identified in the Hunter New England region of New South Wales, Australia on 28 June 2026 and 10 July 2026. These were the first detections of the virus in New South Wales and occurred shortly after the first Australian detection in June 2026. The Hunter New England Population Health Unit managed human contacts of the infected birds using a contact management system designed and purpose-built by the Unit. We report on the public health response and opportunities for improvement.
Vaccination plays a pivotal role in protecting people who are immunocompromised, and who may therefore be at increased risk of infectious diseases, including vaccine preventable diseases (VPDs). However, there are special challenges in clinical practice and the development of immunisation policies to accurately address the vaccination needs of this heterogeneous population. This review aims to highlight the immunisation needs and challenges of immunocompromised populations, and to summarise the rationale behind the immunisation recommendations for these populations in Australia. The chapter Vaccination for people who are immunocompromised, in the Australian Immunisation Handbook, was recently updated by the Australian Technical Advisory Group on Immunisation (ATAGI). The updated chapter introduces new categorisation and risk classification for various types of immunocompromise, alongside the principles of immunisation. When planning immunisation for immunocompromised people, it is crucial to consider their underlying diagnoses, exposure to immunosuppressive therapies, susceptibility to VPDs, and their immune response to vaccination. Strategies to improve protection for immunocompromised persons include booster doses or altered schedules of routine vaccines; additional vaccines to prevent specific VPDs; and complete revaccination following immune reconstitution. Several national and jurisdictional vaccination programs have been implemented for immunocompromised populations (alongside other priority populations); however, monitoring vaccine coverage in these groups is challenging, and strategies to improve coverage are needed. There are significant evidence gaps in vaccine research for immunocompromised people, particularly regarding the optimal timing and scheduling of vaccinations to ensure maximum efficacy and safety. Future research should prioritise the inclusion of immunocompromised people in clinical trials and should integrate evidence from post-licensure use through data linkage. Emerging vaccine technologies may enable the development of more immunogenic vaccines or may offer more effective vaccination strategies for better protection against VPDs in immunocompromised people.
This report describes influenza surveillance activities in Australia in 2019. Data were extracted from several sources constituting the National Influenza Surveillance Scheme. The 2019 influenza season in Australia was characterised by high activity overall, with 2.8 times as many laboratory-confirmed influenza notifications as the five-year mean value. There were an unusually high number of notifications reported in the 2018-2019 interseasonal period; an earlier peak in influenza notifications; and prolonged activity after the peak of the season compared to previous years. There was considerable variation in the timing of peak influenza activity between states and territories; however, this was not unexpected given climatic differences. Notification rates were highest in the 0-4 and 5-9 year age groups, and about 2.1 times higher in these age groups than the overall notification rate. The age-specific notification rates of influenza A were higher than the corresponding rates of influenza B in all age groups in 2019; however, the age-specific notification rate of influenza B was considerably higher among those aged 0-15 years compared to other age groups. In 2019, of laboratory-confirmed influenza notifications, 76.6% were influenza A (71.6% influenza A(unsubtyped), 3.9% A(H3N2) and 1.1% A(H1N1)pdm09) and 23.2% were influenza B. Similar trends were observed across many sentinel surveillance systems for influenza, with each sentinel system showing increased activity during the interseasonal period and earlier peak activity in 2019. High notification rates were reflected in an increase in sentinel hospital admissions with confirmed influenza. The burden placed on hospitals due to people admitted with influenza was high; however, severity (measured through the proportion of patients admitted directly to intensive care units) was moderate. Influenza was recorded as the underlying cause of death for fewer than 1% of all deaths that occurred in 2019.
