Intraseason decline in influenza vaccine effectiveness during the 2016 southern hemisphere influenza season: A test-negative design study and phylogenetic assessment.

BACKGROUND: We estimated the effectiveness of seasonal inactivated influenza vaccine and the potential influence of timing of immunization on vaccine effectiveness (VE) using data from the 2016 southern hemisphere influenza season. METHODS: Data were pooled from three routine syndromic sentinel surveillance systems in general practices in Australia. Each system routinely collected specimens for influenza testing from patients presenting with influenza-like illness. Next generation sequencing was used to characterize viruses. Using a test-negative design, VE was estimated based on the odds of vaccination among influenza-positive cases as compared to influenza-negative controls. Subgroup analyses were used to estimate VE by type, subtype and lineage, as well as age group and time between vaccination and symptom onset. RESULTS: A total of 1085 patients tested for influenza in 2016 were included in the analysis, of whom 447 (41%) tested positive for influenza. The majority of detections were influenza A/H3N2 (74%). One-third (31%) of patients received the 2016 southern hemisphere formulation influenza vaccine. Overall, VE was estimated at 40% (95% CI: 18-56%). VE estimates were highest for patients immunized within two months prior to symptom onset (VE: 60%; 95% CI: 26-78%) and lowest for patients immunized >4 months prior to symptom onset (VE: 19%; 95% CI: -73-62%). DISCUSSION: Overall, the 2016 influenza vaccine showed good protection against laboratory-confirmed infection among general practice patients. Results by duration of vaccination suggest a significant decline in effectiveness during the 2016 influenza season, indicating immunization close to influenza season offered optimal protection.

Understanding influenza vaccine protection in the community: an assessment of the 2013 influenza season in Victoria, Australia.

BACKGROUND: The influenza virus undergoes frequent antigenic drift, necessitating annual review of the composition of the influenza vaccine. Vaccination is an important strategy for reducing the impact and burden of influenza, and estimating vaccine effectiveness (VE) each year informs surveillance and preventative measures. We aimed to describe the influenza season and to estimate the effectiveness of the influenza vaccine in Victoria, Australia, in 2013. METHODS: Routine laboratory notifications, general practitioner sentinel surveillance (including a medical deputising service) data, and sentinel hospital admission surveillance data for the influenza season (29 April to 27 October 2013) were collated in Victoria, Australia, to describe influenza-like illness or confirmed influenza during the season. General practitioner sentinel surveillance data were used to estimate VE against medically-attended laboratory confirmed influenza. VE was estimated using the case test negative design as 1-adjusted odds ratio (odds of vaccination in cases compared with controls) × 100%. Cases tested positive for influenza while non-cases (controls) tested negative. Estimates were adjusted for age group, week of onset, time to swabbing and co-morbidities. RESULTS: The 2013 influenza season was characterised by relatively low activity with a late peak. Influenza B circulation preceded that of influenza A(H1)pdm09, with very little influenza A(H3) circulation. Adjusted VE for all influenza was 55% (95%CI: -11, 82), for influenza A(H1)pdm09 was 43% (95%CI: -132, 86), and for influenza B was 56% (95%CI: -51, 87) Imputation of missing data raised the influenza VE point estimate to 64% (95%CI: 13, 85). CONCLUSIONS: Clinicians can continue to promote a positive approach to influenza vaccination, understanding that inactivated influenza vaccines prevent at least 50% of laboratory-confirmed outcomes in hospitals and the community.

Mortality due to viral hepatitis in the Global Burden of Disease Study 2010: new evidence of an urgent global public health priority demanding action.

The recently published Global Burden of Disease Study 2010 (GBD 2010) contains accurate, contemporary estimates of human morbidity and mortality, with substantial changes in the patterns of illness observed over the last two decades. One of the most significant alterations to these estimates has been the recognition that viral hepatitis is a leading cause of human mortality, with an estimated 1.29 million deaths worldwide in 2010. The global community must act to address emerging health priorities identified by GBD 2010, including the need to provide treatment and care to people living with viral hepatitis, especially in resource-poor settings.

Disease burden and health-care clinic attendances for young children in remote aboriginal communities of northern Australia.

OBJECTIVE: To determine the frequency of presentations and infectious-disease burden at primary health care (PHC) services in young children in two remote Aboriginal communities in tropical northern Australia. METHODS: Children born after 1 January 2001, who were resident at 30 September 2005 and for whom consent was obtained, were studied. Clinic records were reviewed for all presentations between 1 January 2002 and 30 September 2005. Data collected included reason for presentation (if infectious), antibiotic prescription and referral to hospital. FINDINGS: There were 7273 clinic presentations for 174 children aged 0-4.75 years, 55% of whom were male. The median presentation rate per child per year was 16 (23 in the first year of life). Upper-respiratory-tract infections (32%) and skin infections (18%) were the most common infectious reasons for presentation. First presentations for scabies and skin sores peaked at the age of 2 months. By 1 year of age, 63% and 69% of children had presented with scabies and skin sores, respectively. CONCLUSION: These Aboriginal children average about two visits per month to PHC centres during their first year of life. This high rate is testament to the disease burden, the willingness of Aboriginal people to use health services and the high workload experienced by these health services. Scabies and skin sores remain significant health problems, with this study describing a previously undocumented burden of these conditions commencing within the first few months of life. Appropriate prevention and treatment strategies should encompass early infancy to reduce the high burden of infectious diseases in this population.