Predictors of herpes zoster vaccination among Australian adults aged 65 and over.

OBJECTIVE(S): To estimate HZ vaccine coverage in Australia among older Australians and to identify potential barriers to vaccination. DESIGN: Analysis of data from three cross-sectional surveys administered online between 2019 and 2020. SETTING AND PARTICIPANTS: Adults aged 65 and over residing in Australia. MAIN OUTCOME MEASURES: Self-reported herpes zoster vaccination. RESULTS: Among the 744 adults aged 65 and over in this sample, 32% reported being vaccinated for HZ, including 23% of participants aged 65-74, 55% of participants aged 75-84, and 0% for participants aged 85 and above. Those who are vaccinated with other immunisations are more likely to have received HZ vaccine, including seasonal influenza (OR = 4.41, 95 % CI: 2.44-7.98) and pneumococcal vaccines (OR = 4.43, 95 % CI: 2.92 - 6.75). Participants with a history of certain conditions, such as stroke (OR = 2.26, 95 % CI: 1.13-4.49), were more likely to be vaccinated against HZ. Participants that reported smoking tobacco daily were less likely to be vaccinated against HZ (OR = 0.48, 95 % CI: 0.26-0.89). Participants were less likely to be vaccinated against HZ if they preferred to develop immunity 'naturally' (OR = 0.29, 95 % CI: 0.15 - 0.57) or expressed distrust of vaccines (OR = 0.34, 95 % CI: 0.13-0.91). CONCLUSION(S): Further research is required to understand the barriers to HZ vaccine uptake. Increasing the funding eligibility for those who are at risk of complications from shingles, or lowering the age of eligibility, may increase vaccine coverage.

Predictors of pneumococcal vaccination among Australian adults at high risk of pneumococcal disease.

BACKGROUND: Although nearly all Australian children are vaccinated against pneumococcal disease, pneumococcal vaccine uptake is low among high-risk adults. This study aimed to identify perceived barriers to pneumococcal vaccination among high-risk adults. METHODS: This paper reports combined data on pneumococcal vaccination collected from three different online, cross-sectional surveys that were administered in Australia between August 2019 and September 2020. Using Poisson regression, we identified characteristics and beliefs associated with self-reported pneumococcal vaccination among adults aged 65 and over or with chronic health conditions. RESULTS: The weighted estimate for pneumococcal vaccine coverage was 24% for high-risk adults under 65 and 53% for adults aged 65 and over. Nearly half of those under 65 reported they had never heard of the pneumococcal vaccine, while 26% of those aged 65 and over had never heard of the vaccine. Among those under 65, pneumococcal vaccination was associated with high perceived disease susceptibility (PR = 1.97, 95% CI: 1.23, 3.18), not having heard of the pneumococcal vaccine (PR = 0.44, 95% CI: 0.28-0.69), awareness that their chronic health condition puts them at increased risk of pneumonia (PR = 2.44, 95% CI: 1.51-3.98), and having a doctor recommend the vaccine (PR = 3.02, 95% CI: 2.05-4.44). Among adults aged 65 and over, self-reported pneumococcal vaccination was associated with influenza vaccination in the previous 12 months (PR = 4.28, 95% CI: 2.85-6.44) and awareness that they are eligible for free pneumococcal vaccination (PR = 5.02, 95% CI: 2.34-10.77). CONCLUSION: Awareness of pneumococcal vaccines was low among adults at high risk of pneumococcal disease, which appears to be contributing to low vaccine uptake. A doctor's recommendation was associated with increased uptake of pneumococcal vaccine, so interventions should be developed to promote pneumococcal vaccine uptake in GP practices.

Pharmacy, workplace or primary care? Where Australian adults get their influenza vaccines.

OBJECTIVE: To estimate the proportion of influenza vaccines administered in non-medical settings in Australia in 2019 and identify factors associated with vaccination site. METHODS: We surveyed 1,444 Australian adults online in October 2019. To identify factors associated with vaccination site, we used Pearson's chi-square test. We used thematic analysis to describe responses to the question, 'Please explain why you chose to get vaccinated there'. RESULTS: Most participants (73%) received the influenza vaccine in a medical setting, while 13% received it at a pharmacy and 14% at their workplace. Being vaccinated in pharmacy was associated with being under 65 years of age (p<0.01), marital status (p=0.01), and not having a high-risk comorbidity (p<0.01). Workplace vaccination was associated with being under 65 (p<0.01), household income (p<0.01), not having a regular general physician/practice (p=0.01), having private insurance (p<0.01), and not having a high-risk comorbidity (p<0.01). There was no association between site of vaccination and first-time vaccination (p=0.71, p=0.22). CONCLUSIONS: Despite new policies allowing pharmacists to administer influenza vaccines, most Australian adults are still vaccinated in medical settings. Pharmacy and workplace vaccination settings were more common among younger adults without high-risk comorbidities. Implications for public health: Workplaces, pharmacies and other non-medical settings may provide an opportunity to increase influenza vaccination among healthy, working-age adults who might otherwise forego annual vaccination. Pharmacies may also provide a convenient location for the rollout of the COVID-19 vaccine, particularly in medically underserved areas.

Using the health belief model to identify barriers to seasonal influenza vaccination among Australian adults in 2019.

BACKGROUND: Each year tens of thousands of Australians become ill with influenza, resulting in thousands of severe infections that require hospitalisation. However, only 40% of adults receive the annual influenza vaccine. We surveyed Australian adults to provide up to date, population-specific data on the predictors and barriers of seasonal influenza vaccination. METHODS: We administered an online survey to a nationally representative sample of Australian adults. We designed survey questions using the theoretical constructs of the health belief model. Using simple and multivariable Poisson regression, we identified attitudes and beliefs associated with influenza vaccination in 2019. RESULTS: Among 1,444 respondents, 51.7% self-reported influenza vaccination in 2019. We estimated vaccine coverage to be 44% for adults under 45, 46% for adults aged 45 to 64 and 77% for adults aged 65 and over. The strongest individual predictors of self-reported vaccination were believing the vaccine is effective at preventing influenza (APR = 3.71; 95% CI = 2.87-4.80), followed by recalling their doctor recommending the vaccine (APR = 2.70; 95% CI = 2.31-3.16). Common perceived barriers that predicted self-reported vaccination included believing the vaccine could give you influenza (APR = 0.59; 95% CI = 0.52-0.67), believing the vaccine can make you ill afterwards (APR = 0.68; 95% CI = 0.62-0.74) and preferring to develop immunity "naturally" (APR = 0.38; 95% CI = 0.32-0.45). CONCLUSION: Although vaccine uptake in 2019 appears to be higher than previous years, there are perceived barriers which may limit uptake among Australians. Tailored interventions are needed to combat widespread influenza vaccine hesitancy, particularly among high-risk groups.

Serological Immunity to Smallpox in New South Wales, Australia.

The re-emergence of smallpox is an increasing and legitimate concern due to advances in synthetic biology. Vaccination programs against smallpox using the vaccinia virus vaccine ceased with the eradication of smallpox and, unlike many other countries, Australia did not use mass vaccinations. However, vaccinated migrants contribute to population immunity. Testing for vaccinia antibodies is not routinely performed in Australia, and few opportunities exist to estimate the level of residual population immunity against smallpox. Serological data on population immunity in Australia could inform management plans against a smallpox outbreak. Vaccinia antibodies were measured in 2003 in regular plasmapheresis donors at the Australian Red Cross Blood Service from New South Wales (NSW). The data were analysed to estimate the proportion of Australians in NSW with detectable serological immunity to vaccinia. The primary object of this study was to measure neutralising antibody titres against vaccinia virus. Titre levels in donor samples were determined by plaque reduction assay. To estimate current levels of immunity to smallpox infection, the decline in geometric mean titres (GMT) over time was projected using two values for the antibody levels estimated on the basis of different times since vaccination. The results of this study suggest that there is minimal residual immunity to the vaccinia virus in the Australian population. Although humoral immunity is protective against orthopoxvirus infections, cell-mediated immunity and immunological memory likely also play roles, which are not quantified by antibody levels. These data provide an immunological snapshot of the NSW population, which could inform emergency preparedness planning and outbreak control, especially concerning the stockpiling of vaccinia vaccine.

Persistence of immunity to conjugate and polysaccharide pneumococcal vaccines in frail, hospitalised older adults in long-term follow up.

BACKGROUND: Data on long-term antibody responses to pneumococcal vaccines in the elderly, especially the frail elderly at greatest risk of severe disease, are limited. We followed up participants in a randomised trial of the immunogenicity of 23-valent polysaccharide vaccine (23vPPV) and 7 valent pneumococcal conjugate vaccines (PCV7) in hospitalised older adults. METHODS: We measured antibody to vaccine serotypes by standardised enzyme-linked immunosorbent assay (ELISA) and opsonophagocytic (OPA) assays. A follow up study was conducted six years after vaccination with 23vPPV alone or with PCV7 followed by 23vPPV six months later. RESULTS: Of 215 surviving trial participants, 136 (63%) completed follow up; 62 received 23vPPV and 74 received PCV7 + 23vPPV. There was no significant difference in death and readmission between arms. Antibody levels by ELISA and OPA did not differ significantly between the two study arms at 72 months post-vaccination. ELISA and OPA antibody remained higher than baseline except for OPA antibody to 4, 6A, 6B, 9v, 19F and 23F, including in subjects with undetectable immunity at baseline. DISCUSSION: While ELISA responses in both study arms remained high 6 years post-vaccination, considerable waning was observed by OPA in both study arms, which should be considered given the current single-dose recommendation in Australia. Further research is needed to inform pneumococcal vaccine recommendations in people over the age of 65.

Parental opinions towards the "No Jab, No Pay" policy in Australia.

BACKGROUND: In 2016, Australia introduced the "No Jab, No Pay" legislation, which removed the option of non-medical exemptions from the vaccination requirements to receive certain family and child care tax benefits. We aimed to gauge parental support for "No Jab, No Pay" and explore how it has impacted parental attitudes towards vaccination, particularly among families that are reliant on the tax benefits linked to vaccination under "No Jab, No Pay". METHODS: An online survey distributed to parents with children under 5 in Australia assessed parental knowledge and opinions towards childhood vaccination and the "No Jab, No Pay" policy. RESULTS: A total of 411 parents completed the survey. The majority of parents reported their child was either fully vaccinated or they intended to fully vaccinate. Eighty-two percent of parents were in favour of "No Jab, No Pay." The belief that vaccine-preventable diseases are a significant risk to unvaccinated children was a predictor of supporting the "No Jab, No Pay" policy (AOR = 5.95, 95% CI = [3.60, 10.94], p < 0.001). Parents that depend on the financial benefits associated with "No Jab, No Pay" and parents that utilize child care services were significantly more likely to reconsider vaccination, if they previously hesitated or objected, because of the policy (AOR = 9.66, 95% CI = [4.98, 18.72], p < 0.001 and AOR = 2.09, 95% CI = [1.04, 4.17], p = 0.04). CONCLUSION: We found that there is widespread support for "No Jab, No Pay" among parents of young children, but parents that depend on the financial benefits or utilize child care services may be disproportionately affected by the policy. Childhood vaccination coverage in Australia could best be improved by increasing access to vaccination services and by imposing significant administrative barriers to obtaining non-medical exemptions.