Influenza and pertussis vaccine coverage in pregnancy in Australia, 2016-2021.

Vaccination in pregnancy is the best strategy to reduce complications from influenza or pertussis infection in infants who are too young to be protected directly from vaccination. Pregnant women are also at risk of influenza complications preventable through antenatal vaccination. Both vaccines are funded under the National Immunisation Program for pregnant women in Australia, but coverage is not routinely reported nationally. We reviewed all reported Australian maternal influenza and pertussis vaccine coverage data for the period 2016-2021, to identify gaps and information needs. Maternal influenza vaccine coverage was suboptimal at < 58% for 2016-2018, with higher coverage of 62-75% reported in two states (Victoria and Western Australia) for 2019-2021. Maternal pertussis vaccine coverage from 2016 was generally higher than for influenza at > 70%, with the highest jurisdictional coverage of 89% reported in Western Australia in 2020. Vaccination rates were often suboptimal among First Nations pregnant women and up to 20% lower than among non-First Nations Australian women; while data were limited, coverage was low among culturally and linguistically diverse women and among women of lower socio-economic status. Jurisdictional perinatal data collections were the best source of information on antenatal vaccine coverage but were only available for a minority of the population; a nationally consistent systematic approach is lacking. Timely and comprehensive data are needed to provide feedback to improve maternal vaccination coverage, particularly among groups with higher risk and/or low uptake, and as new vaccines are recommended, including COVID-19 vaccination.

Seroprevalence of SARS-CoV-2-specific antibodies in Sydney after the first epidemic wave of 2020.

OBJECTIVES: To estimate SARS-CoV-2-specific antibody seroprevalence after the first epidemic wave of coronavirus disease 2019 (COVID-19) in Sydney. SETTING, PARTICIPANTS: People of any age who had provided blood for testing at selected diagnostic pathology services (general pathology); pregnant women aged 20-39 years who had received routine antenatal screening; and Australian Red Cross Lifeblood plasmapheresis donors aged 20-69 years. DESIGN: Cross-sectional study; testing of de-identified residual blood specimens collected during 20 April - 2 June 2020. MAIN OUTCOME MEASURE: Estimated proportions of people seropositive for anti-SARS-CoV-2-specific IgG, adjusted for test sensitivity and specificity. RESULTS: Thirty-eight of 5339 specimens were IgG-positive (general pathology, 19 of 3231; antenatal screening, 7 of 560; plasmapheresis donors, 12 of 1548); there were no clear patterns by age group, sex, or location of residence. Adjusted estimated seroprevalence among people who had had general pathology blood tests (all ages) was 0.15% (95% credible interval [CrI], 0.04-0.41%), and 0.29% (95% CrI, 0.04-0.75%) for plasmapheresis donors (20-69 years). Among 20-39-year-old people, the age group common to all three collection groups, adjusted estimated seroprevalence was 0.24% (95% CrI, 0.04-0.80%) for the general pathology group, 0.79% (95% CrI, 0.04-1.88%) for the antenatal screening group, and 0.69% (95% CrI, 0.04-1.59%) for plasmapheresis donors. CONCLUSIONS: Estimated SARS-CoV-2 seroprevalence was below 1%, indicating that community transmission was low during the first COVID-19 epidemic wave in Sydney. These findings suggest that early control of the spread of COVID-19 was successful, but efforts to reduce further transmission remain important.

"No jab, no pay": catch-up vaccination activity during its first two years.

OBJECTIVES: To assess catch-up vaccination of older children and adolescents during the first two years of the "No jab, no pay" policy linking eligibility for federal family assistance payments with childhood vaccination status. DESIGN, SETTING, PARTICIPANTS: Cross-sectional analysis of Australian Immunisation Register data on catch-up vaccination of children aged 5 to less than 7 years before (January 2013 - December 2014; baseline) and during the first two years of "No jab, no pay" (December 2015 - December 2017), and of children aged 7 to less than 10 years and young people aged 10 to less than 20 years ("No jab, no pay" period only). MAIN OUTCOMES: Catch-up vaccination rates for measles-mumps-rubella vaccine second dose (MMR2), by age group, Indigenous status, and socio-economic status; catch-up vaccination of children aged 5 to less than 7 years (third dose of diphtheria-tetanus-pertussis vaccine [DTPa3], MMR1), before and after introduction of "No jab, no pay". RESULTS: The proportion of incompletely vaccinated children aged 5 to less than 7 years who received catch-up DTPa3 was higher under "No jab, no pay" than during the baseline period (15.5% v 9.4%). Of 407 332 incompletely vaccinated people aged 10 to less than 20 years, 71 502 (17.6%) received catch-up MMR2 during the first two years of "No jab, no pay", increasing overall coverage for this age group from 86.6% to 89.0%. MMR2 catch-up activity in this age group was greater in the lowest socio-economic status areas than in the highest status areas (29.1% v 7.6%), and also for Indigenous than for non-Indigenous Australians (35.8% v 17.1%). MMR2 catch-up activity in 2016 and 2017 peaked mid-year. CONCLUSIONS: Linking family assistance payments with childhood vaccination status and associated program improvements were followed by substantial catch-up vaccination activity, particularly in young people from families of lower socio-economic status.

Closing the vaccination coverage gap in New South Wales: the Aboriginal Immunisation Healthcare Worker Program.

OBJECTIVES: To assess vaccination coverage and timeliness among Indigenous and non-Indigenous children in New South Wales and the rest of Australia, with a particular focus on changes in the vaccination coverage gaps after the introduction of the Aboriginal Immunisation Healthcare Worker (AIHCW) Program in NSW in 2012. DESIGN: Cross-sectional analysis of Australian Immunisation Register data (2008-2016). MAIN OUTCOME MEASURES: Annual estimates of full vaccination coverage at 9, 15 and 51 months of age for Indigenous and non-Indigenous children in NSW and the rest of Australia; differences in coverage between Indigenous and non-Indigenous children at each milestone. RESULTS: The proportion of Indigenous and non-Indigenous children classified as fully vaccinated at 9, 15, and 51 months increased significantly in both NSW and the rest of Australia after the introduction of the AIHCW Program. The mean annual difference in full vaccination coverage between Indigenous and non-Indigenous children in NSW aged 9 months declined from 6.6 (95% CI, 5.2-8.0) during 2008-2011 to 3.7 percentage points (95% CI, 2.5-4.8) during 2012-2016; for those aged 15 months it declined from 4.6 (95% CI, 3.1-6.0) to 2.2 percentage points (95% CI, 1.0-3.4), and for those aged 51 months it declined from 8.5 (95% CI, 7.2-9.8) to 0.6 percentage points (95% CI, -0.6 to 1.8). Reductions in the differences in coverage were not as marked in the rest of Australia. In 2016, there was no statistically significant difference in coverage at any of the three milestones in NSW: at 9 months the difference was 1.6 percentage points (95% CI, -1.0 to 4.1); at 15 months, 0.4 percentage points (95% CI, -2.2 to 2.9); and at 51 months, -1.8 percentage points (95% CI, -4.4 to 0.8). CONCLUSION: Our findings suggest that a dedicated program can help overcome barriers to timely vaccination and significantly improve timely vaccination rates in Indigenous Australian children.

Evaluation of bacille Calmette-Guérin immunisation programs in Australia.

BACKGROUND: bacille Calmette-Guérin (BCG) immunisation programs in Australia are funded and operated by the individual states and territories. In recent years BCG vaccine shortages have required use of unregistered products. We aimed to evaluate BCG immunisation programs in Australia, with particular reference to program implementation and national consistency.
 Methods: Between September and November 2015, 12 key stakeholders, representing Australian states and territories, completed surveys. We analysed BCG vaccination coverage data from the Australian Childhood Immunisation Register (ACIR), and data on adverse events following immunisation (AEFI) with BCG vaccine from the Therapeutic Goods Administration's Adverse Drug Reactions System, for 2001 to 2014.
 Results: Access to BCG vaccination varies between jurisdictions, with some states providing this only in major city locations. Analysis of ACIR data suggests significant differences in vaccine delivery between jurisdictions, but varying levels of under-reporting to the ACIR were also acknowledged. The rate of BCG AEFI appeared to increase between 2011 and 2014; however, these data need to be interpreted with caution due to small numbers, likely under-reporting of both numerator (AEFI) and denominator (vaccine doses administered), and the general increase in reporting of AEFI related to other vaccines in children over this period.
 Conclusions: BCG immunisation programs aim to prevent severe forms of tuberculosis in young children who live in or travel to high burden settings. A range of factors, particularly inconsistent vaccine supply are leading to low, variable and inequitable vaccine delivery across Australian jurisdictions. Improved BCG vaccination uptake and AEFI data quality are required for accurate monitoring of program delivery and vaccine safety - this is particularly important given the current need to use unregistered vaccines. Improved and consistent access to BCG vaccine is suggested to optimise equity for at-risk children Australia-wide.

Immunisation coverage annual report, 2014.

This 8th annual immunisation coverage report shows data for 2014 derived from the Australian Childhood Immunisation Register and the National Human Papillomavirus Vaccination Program Register. This report includes coverage data for 'fully immunised' and by individual vaccines at standard age milestones and timeliness of receipt at earlier ages according to Indigenous status. Overall, 'fully immunised' coverage has been mostly stable at the 12- and 24-month age milestones since late 2003, but at 60 months of age, it has increased by more than 10 percentage points since 2009. As in previous years, coverage for 'fully immunised' at 12 months of age among Indigenous children was 3.7% lower than for non-Indigenous children overall, varying from 6.9 percentage points in Western Australia to 0.3 of a percentage point in the Australian Capital Territory. In 2014, 73.4% of Australian females aged 15 years had 3 documented doses of human papillomavirus vaccine (jurisdictional range 67.7% to 77.4%), and 82.7% had at least 1 dose, compared with 71.4% and 81.5%, respectively, in 2013. The disparity in on-time vaccination between Indigenous and non-Indigenous children in 2014 diminished progressively from 20.2% for vaccines due by 12 months to 11.5% for those due by 24 months and 3.0% at 60 months of age.

Trends and patterns in vaccination objection, Australia, 2002-2013.

OBJECTIVES: To examine geographic and demographic trends in objection to vaccination in Australia. DESIGN: Cross-sectional analysis of Australian Childhood Immunisation Register (ACIR) data (2002-2013) for children aged 1-6 years. MAIN OUTCOME MEASURES: Immunisation status according to whether an objection had been registered, and remoteness and socio-economic status of area of residence. Registration of children with Medicare after 12 months of age was used as a proxy indicator of being overseas-born. RESULTS: The proportion of children affected by a registered vaccination objection increased from 1.1% in 2002 to 2.0% in 2013. Children with a registered objection were clustered in regional areas. The proportion was lower among children living in areas in the lowest decile of socio-economic status (1.1%) than in areas in the highest socio-economic decile (1.9%). The proportion not affected by a recorded objection but who were only partly vaccinated for vaccines due at 2, 4 and 6 months of age was higher among those in the lowest decile (5.0% v 3.4%), suggesting problems of access to health services, missed opportunities, and logistic difficulties. The proportion of proxy overseas-born for whom neither vaccinations nor an objection were recorded was 14 times higher than for other children (17.1% v 1.2%). These children, who are likely to be vaccinated although this is not recorded on the ACIR, resided predominantly in major cities. CONCLUSIONS: There was a small increase in registered objection rates since 2002. We estimate that 3.3% of children are affected by registered or presumptive (unregistered) vaccination objection, which suggests that the overall impact of vaccination objection on vaccination rates has remained largely unchanged since 2001. Incomplete records, barriers to access, and missed opportunities are likely to be responsible for most other deficiencies in vaccination coverage.

Summary of National Surveillance Data on Vaccine Preventable Diseases in Australia, 2008-2011.

This summary report on vaccine preventable diseases in Australia brings together the 3 most important national sources of routinely collected data on vaccine preventable diseases (notifications, hospitalisations and deaths) for all age groups for the period January 2008 to December 2011. The general trend towards improved control of disease is evident, particularly in the childhood years. Detailed results are available in 16 individual chapters. Although these data have limitations, which are discussed in detail in the body of the report, some clear trends are evident. Compared with the previous review period (2005-2007), there are continuing declines in the overall disease burden, driven by improving control of mumps, rubella, hepatitis B and meningococcal disease. There is an ongoing absence of disease due to polio and a continuing low incidence of tetanus. There have been continuing declines in the incidence of hepatitis A and B. However, there were 4 notified cases of diphtheria in 2011; prior to these reports there had been no notified diphtheria cases since 2001. Influenza and pertussis notifications have increased, whereas notifications and hospitalisations for mumps have remained stable and for meningococcal disease have declined. Influenza, pertussis and pneumococcal disease continue to contribute the greatest burden of serious disease.

Adverse events following immunisation with bacille Calmette-Guérin vaccination: baseline data to inform monitoring in Australia following introduction of new unregistered BCG vaccine.

In recent years there has been a global shortage of bacille Calmette-Guérin (BCG) vaccine and, from September 2012, unregistered vaccines have needed to be used in Australia (a Danish product initially until the end of 2015, and a Polish product used in some jurisdictions from early 2016). We examined rates and types of adverse events following immunisation (AEFI) with BCG vaccine reported to the Therapeutic Goods Administration between 2009 and 2014 in children aged less than 7 years. Reporting rates of AEFI with BCG vaccine increased from 87 per 100,000 doses (registered Sanofi Pasteur product) in 2009 to 201 per 100,000 doses (unregistered Danish Statens Serum Institute product) in 2014, with Victoria having the highest rate each year. Substantial variation between jurisdictions exists, suggesting differential reporting of BCG vaccine doses administered and/or BCG vaccine-related AEFI. The most commonly reported reactions were abscess (31%), injection site reaction (27%) and lymphadenopathy/lymphadenitis (17%). This study provides baseline data on BCG vaccine safety to inform surveillance. Given the current use of unregistered vaccines in the context of vaccine supply issues, improved recording of both administered BCG vaccine doses and the reporting of BCG vaccine-related AEFI are required to facilitate close monitoring of vaccine safety.

Rise in invasive serogroup W meningococcal disease in Australia 2013-2015.

Since 2013, there has been an increase in the number of notified cases of invasive meningococcal disease (IMD) due to serogroup W (MenW) in Australia. In response to this observed increase, the Communicable Diseases Network Australia convened a working group in 2015 to collate and analyse the epidemiology of MenW disease nationally. Enhanced surveillance data collected by jurisdictions were collated and analysed, and whole genome sequencing (WGS) of MenW isolates assessed the genomic relatedness of strains between 2012 and 2015. This report describes that epidemiology. Since 2013, the incidence and proportion of MenW has increased in Australia, rising from an average of 2% of all IMD cases annually (range 0% to 5%) between 1991 and 2012; to 8% (12/149) of cases in 2013, 10% (17/169) in 2014, and 19% (34/182) in 2015. Victoria has been the main affected state, with 50% (17/34) of national cases in 2015. MenW has affected older populations, with a median age between 2003 and 2015 being 44 years. During this period, case fatality was 10.7% (17/159), 2.3 times higher than for all IMD serogroups combined (4.7%, 173/3720). There were 7 deaths due to MenW in 2015 (CFR 21%). WGS has found the majority of Australian isolates cluster within a group of W:P1.5,2:F1-1:ST11 isolates from the United Kingdom and South America, regions where rapid spread and endemic transmission has occurred since 2009. The recent increase in incidence of MenW in Australia is evolving and is being closely monitored. Lessons learned from the international experience will be important in informing the public health response.

Australian vaccine preventable disease epidemiological review series: Influenza 2006 to 2015.

INTRODUCTION: Influenza is a major contributor to the preventable health burden of Australians each year. The National Immunisation Program provides influenza vaccine for those at highest risk of severe disease. This review of influenza epidemiology examines current data on influenza disease burden in Australia, in the context of several comparable countries having programs with much broader eligibility for influenza vaccine in children. METHODS: Influenza notifications (2006-2015), hospitalisations, and deaths (2006-2013) were sourced and age-specific rates calculated. Comparisons were made across age groups in the pre-pandemic, pandemic, and post-pandemic periods and by Indigenous and non-Indigenous status. RESULTS: The 2009 pandemic year and the 2012 non-pandemic season resulted in the highest rates of notification, hospitalisation and death. Influenza notification rates were 4.0 times higher and hospitalisation rates 2.1 times higher during 2011-2013 compared with 2006-2008. Death rates varied widely, but peaks corresponded to high-activity seasons. Influenza hospitalisation rates were highest among those aged <5 and ≥65 years, but influenza-attributable deaths were identified primarily in those aged ≥75 years. Significantly higher notification and hospitalisation rates were seen for all Indigenous people, but higher death rates were largely restricted to the 2009 pandemic year. CONCLUSIONS: Based on notifications, hospitalisations and deaths, burden of disease from influenza is highest at the extremes of life and is significantly higher among Indigenous people of all ages. This pattern of disease burden warrants consideration of widened eligibility for influenza vaccine under the National Immunisation Program to all Indigenous people and all children less than 5 years of age.

Pertussis immunisation in pregnancy: a summary of funded Australian state and territory programs.

The Australian Immunisation Handbook, 10th edition now recommends pertussis vaccination during pregnancy as the preferred option for protecting vulnerable young infants. Jurisdictionally funded pertussis immunisation programs for pregnant women have been progressively introduced in all Australian states and territories between August 2014 and June 2015. A meeting convened by the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases was held on 31 May 2015 to share information regarding jurisdictional policies and program implementation. This report of that meeting provides the first published comparison of these jurisdictional programs, which are of a broadly similar nature but with important differences. Monitoring and evaluation of the uptake, safety and impact of the current programs in Australia will be important to inform future policy decisions.

Disseminated varicella zoster virus infection following live attenuated herpes zoster vaccine: descriptive analysis of reports to Australia's spontaneous vaccine pharmacovigilance system, 2016-2020.

OBJECTIVES: To examine the reported incidence and features of disseminated varicella zoster virus (VZV) infection following live attenuated herpes zoster vaccine live (ZVL: Zostavax, Merck) in immunocompromised people in Australia. DESIGN AND SETTING: ZVL was funded in 2016 in Australia for people aged 70 years, with a catch-up programme for those 71-79 years. From 2016 to 2020, three deaths due to disseminated vaccine-strain VZV infection occurred following inadvertent ZVL administration in individuals with varying levels of immunocompromise. This descriptive study examined 4 years of national surveillance data reported to the Therapeutic Goods Administration's Adverse Event Monitoring System (AEMS). Denominator data for rates were from doses recorded in the Australian Immunisation Register. PARTICIPANTS: Individuals vaccinated between 1 November 2016 and 31 December 2020 who experienced adverse event(s) following immunisation (AEFI) after ZVL recorded in the AEMS. PRIMARY AND SECONDARY OUTCOME MEASURES: Rates and outcomes of confirmed (Oka strain positive) or probable disseminated VZV infection, and inadvertent administration of ZVL in immunocompromised individuals. RESULTS: 854 AEFI were reported from 1 089 966 doses of ZVL administered (78.4 per 100 000 doses). Of those, 14 were classified as confirmed (n=6, 0.55 per 100 000) or probable (n=8) disseminated VZV infection. The confirmed cases were all hospitalised, and most (5/6) were immunocompromised; three cases died. Thirty-seven individuals were reported as vaccinated despite a contraindication due to immunocompromise (3.4 per 100 000), with 12/37 (32%) hospitalised. CONCLUSIONS: Disseminated VZV is potentially life-threatening and occurs mostly in those with severe immunocompromise. Inadvertent administration of ZVL to immunocompromised individuals has occurred despite initial provider guidance and education. Multiple additional strategies to assist providers to identify contraindications have been implemented to prevent adverse outcomes.