The Aboriginal gap in online active vaccine safety surveillance

Objectives: To investigate if Aboriginal people are equally included in new forms of vaccine safety post-marketing surveillance that support safety signal detection and confidence in the vaccine program by comparing the use of Vaxtracker active adverse events following immunisation (AEFI) surveillance between Aboriginal and non-Aboriginal parents of vaccinated children. Methods: In 2016, automated AEFI surveillance was conducted to monitor seasonal influenza vaccine in children aged 18 months to less than 5 years and for DTPa vaccine after the inclusion of a new dose at 18 months of age. To explore reasons for non-response, Aboriginal Immunisation Officers contacted the parents/carers of 24 (48.0%) Aboriginal children and 31 (26.7%) non-Aboriginal children who did not respond to the online survey. Results: There were differential response rates for both vaccines between Aboriginal and non-Aboriginal enrolees; 56.4% vs 76.8% (p=0.005) and 55.1% vs 78.2% (p Conclusion: New systems of vaccine safety surveillance may not adequately include Aboriginal people. Implications: Vaccine safety surveillance systems need to be designed to ensure high levels of participation and response from Aboriginal people

A Discrete-Event, Simulated Social Agent-Based Network Transmission (DESSABNeT) model for communicable diseases: Method and validation using SARS-CoV-2 data in three large Australian cities

IMPORTANCE: During pandemics Agent Based Models (ABMs) can model complex, fine-grained behavioural interactions occurring in social networks, that contribute to disease transmission by novel viruses such as SARS-CoV-2. OBJECTIVE: We present a new agent-based model (ABM) called the Discrete-Event, Simulated Social Agent based Network Transmission model (DESSABNeT) and demonstrate its ability to model the spread of COVID-19 in large cities like Sydney, Melbourne and Gold Coast. Our aim was to validate the model with its disease dynamics and underlying social network. DESIGN: DESSABNeT relies on disease transmission within simulated social networks. It employs an epidemiological SEIRD+M (Susceptible, exposed, infected, recovered, died and managed) structure. One hundred simulations were run for each city, with simulated social restrictions closely modelling real restrictions imposed in each location. MAIN OUTCOME(S) AND MEASURE(S): The mean predicted daily incidence of COVID-19 cases were compared to real case incidence data for each city. R(eff) and health service utilisation outputs were compared to the literature, or for the Gold Coast with daily incidence of hospitalisation. RESULTS: DESSABNeT modelled multiple physical distancing restrictions and predicted epidemiological outcomes of Sydney, Melbourne and the Gold Coast, validating this model for future simulation work. CONCLUSIONS AND RELEVANCE: DESSABNeT is a valid platform to model the spread of COVID-19 in large cities in Australia and potentially internationally. The platform is suitable to model different combinations of social restrictions, or to model contact tracing, predict, and plan for, the impact on hospital and ICU admissions, and deaths; and also the rollout of COVID-19 vaccines and optimal social restrictions during vaccination

School-based HPV vaccination positively impacts parents’ attitudes toward adolescent vaccination

Introduction This qualitative study aimed to explore parental attitudes, knowledge and decision-making about HPV vaccination for adolescents in the context of a gender-neutral school-based Australian National Immunisation Program (NIP). Methods Semi-structured interviews with parents of adolescents eligible for HPV vaccination were undertaken as part of an evaluation of a cluster-randomised controlled trial of a complex intervention in 40 schools (2013–2015). In this qualitative study, we purposively recruited a nested sample of parents from 11 schools across two Australian jurisdictions. Interviews explored parent knowledge and understanding of the HPV vaccine program; HPV vaccination decision-making; their adolescent’s knowledge about HPV vaccination; and their adolescent’s understanding about HPV vaccination, sexual awareness and behaviour. Transcripts were analysed using inductive and deductive thematic analysis. Results Parents’ of 22 adolescents had positive attitudes towards the program; the school-based delivery platform was the key driver shaping acceptance of and decision-making about HPV vaccination. They had difficulty recalling, or did not read, HPV vaccination information sent home. Some adolescents were involved in discussions about vaccination, with parents’ responsible for ultimate vaccine decision-making. All parents supported in-school education for adolescents about HPV and HPV vaccination. Parents’ knowledge about HPV vaccination was limited to cervical cancer and was largely absent regarding vaccination in males. Conclusions Parents’ positive attitudes towards the NIP and inclusion of the HPV vaccine is central to their vaccine decision-making and acceptance. More intensive communication strategies including school education opportunities are required to improve parents’ knowledge of HPV-related disease and to promote vaccine decision-making with adolescents

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND: Live attenuated varicella vaccines for the prevention of varicella (chickenpox) has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States. However, many countries do not routinely immunise children against varicella, and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP). OBJECTIVE: To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults. CRITERIA FOR CONSIDERING STUDIES FOR THIS REVIEW: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008, Issue 1); MEDLINE (1966 to February 2008); and EMBASE (January 1990 to February 2008). SELECTION CRITERIA: RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse effects following vaccination. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted and analysed data using Review Manager software. MAIN RESULTS: Three studies involving 110 healthy children who were siblings of household contacts were identified as suitable for inclusion. The studies varied in quality, study design, vaccine used, and outcomes measured and, as such, were not suitable for meta-analysis. Overall, 13 out of 56 vaccine recipients (18%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with less than 50 skin lesions). In the three studies, most subjects received PEP within three days following exposure; too few subjects were vaccinated four to five days post exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included studies reported on adverse events following immunisation. AUTHORS CONCLUSIONS: These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. No RCTs for adolescents or adults were identified. However safety was not adequately addressed