Vaccination In Australia Research Articles

BCG vaccine in Australia

BCG vaccine in Australia

Assessment of a low virulence Australian isolate of Anaplasma marginale for pathogenicity, immunogenicity and transmissibility by Boophilus microplus

A 14-year-old cow (Dawn) born and kept in a Boophilus microplus-free region gave birth to a calf, which showed the presence of an Anaplasma marginale infection after splenectomy. The calf’s grand dam was from a B. microplus infected area and we assume the infection originated via the transplacental route over two generations. An isolate, prepared from the calf, had similar or lower pathogenicity as Anaplasma centrale, and previously exposed steers were resistant to challenge by four A. marginale field isolates. Two attempts to transmit the isolate using B. microplus were unsuccessful. Our results indicate that Dawn A. marginale may be a useful vaccine in Australia and warrants larger scale validation of its safety and potency locally as well as of the protection it affords against African and New World isolates.

The cost-effectiveness of pneumococcal conjugate vaccination in Australia

Background: Pneumococcal conjugate vaccine, 7 valent (PCV7) is the most costly vaccine yet considered for publicly funded programs. In mid 2001, Australia funded PCV7 for high-risk groups only (indigenous children and children with certain underlying medical conditions). World wide, non-industry-funded studies and studies using cost–utility measures are sparse. We undertook an independent economic analysis of PCV7 compared with no vaccination in the non high-risk Australian childhood population using cost–utility and cost-effectiveness measures. Methods: The incidence of invasive pneumococcal disease (IPD), non-bacteraemic pneumonia and otitis media was estimated using representative urban Australian data, or by extrapolation from comparable industrialised countries. A decision-analytic model was developed for a hypothetical birth cohort using the age-specific vaccine coverage from the Californian randomised controlled trial of PCV7. Health outcomes were measured by life-years saved and deaths and disability-adjusted life-years (DALYs) averted. In line with government guidelines, only direct costs were considered in 1997–1998 Australian dollars. Results: For a birth cohort of 250,000, the gross cost of vaccination is $ 78.6 million. Subtracting treatment cost savings, the net cost (discounted) is $ 61.7 million. In undiscounted terms, vaccination prevents 13.7 deaths, 11.2 (82%) from IPD and the remainder from non-bacteraemic pneumonia. The discounted cost per death avoided is $ 5.0 million, per life-year saved $ 230,130 and per DALY averted $ 121,100, giving a break-even vaccine price of $ 15.40 per dose. These estimates are most sensitive to the unit cost per dose of vaccine, estimates of incidence and vaccine efficacy against non-bacteraemic pneumonia and the discount rate. The cost per DALY reduced to $ 81,000 with a discount rate of 3% rather than 5% and to $ 90,000 with the most favourable assumptions concerning pneumonia reduction. Discussion: With a vaccine price of $ 90 per dose, mid-range estimates of impact against non-bacteraemic pneumonia, and discount rate of 5%, a PCV7 program for infants not at high risk of IPD is at the upper limit of cost per DALY previously approved under Australian pharmaceutical funding guidelines. The impact of PCV7 against non-bacteraemic pneumonia is poorly defined, but its importance to cost-effectiveness in resource rich and resource poor settings warrants further studies or analysis to give greater precision to this outcome.

Overcoming constraints to meeting increased demand for Babesia bigemina vaccine in Australia

Demand for live trivalent tick fever vaccine containing Babesia bovis, Babesia bigemina and Anaplasma centrale produced by the Department of Primary Industries, Queensland, has increased from less than 10,000 doses in 1988 to 500,000 doses in 2001. This paper describes a series of trials aimed at overcoming certain constraints to obtain B. bigemina parasitised erythrocytes (PEs) on a large enough scale from infected splenectomised calves to meet the demand. Passage through a series of splenectomised calves failed to increase the yield per calf but we showed that the dose rate of infected cells could be reduced from the long-time standard of 1×10 7 to 2.5×10 6 without affecting immunogenicity and still leaving a safety margin of at least 50-fold for infectivity. This change quadrupled the potential yield of doses per calf and allowed the DPI to meet the increased demand for B bigemina in vaccine. Due to the high cost and limited availability of suitable, health tested donors, calves previously infected with B. bovis or A. centrale were used to provide B. bigemina organisms but the practice resulted in red cell agglutination in some batches of prepared vaccine. A trial is described where B. bigemina-infected red cells were washed by centrifugation to remove agglutinating antibodies. Washing had no effect on parasite viability and this method is now in routine use in the production of trivalent vaccine.

Influenza virus vaccine live intranasal--MedImmune vaccines: CAIV-T, influenza vaccine live intranasal.

Influenza virus vaccine live intranasal--MedImmune vaccines: CAIV-T, influenza vaccine live intranasal.

Programmes to boost vaccination in Australia, Zambia

Programmes to boost vaccination in Australia, Zambia

Reply

10 October 2001 Dear Editor REPLY Dr Thies is correct that there are economic arguments against the birth dose of hepatitis B vaccine in Australia, a country of low endemicity. However, these arguments assume that selective vaccination of high-risk neonates is well implemented. An effective control strategy must focus on preventing chronic carriage, as chronic carriers are the main reservoir of infection.1 The risk of carriage is inversely proportional to age, with neonates being at highest risk of becoming carriers.2 A vaccination programme for newborns will have a much greater impact on carriage rates than one at 2 months of age because the risk of chronic carriage is highest (up to 90%) in the neonate. Dr Thies states that he has found ‘no evidence’ of poor implementation of selective programmes, but does not provide any references to support this lack of ‘evidence’. I can only assume he is speaking anecdotally. There are studies from several countries that do provide evidence that vaccination of neonates born to carrier mothers is variably implemented, and that completion of the full schedule of vaccination is poor.3-5 In addition, antenatal screening for hepatitis B, despite the existence of screening policies, is variable.3 Provider factors can have a significant impact on vaccine uptake.3 Although it is quite reasonable (and desirable) to question and evaluate policy, it is unhelpful when providers send mixed messages about national vaccination policy to their patients. The bottom line is that global eradication of hepatitis B cannot be achieved with selective vaccination. The same rationale lies behind the need for continued universal vaccination against poliomyelitis in Australia, despite a very low risk in this country. It is interesting that resistance by health professionals to universal polio vaccination does not seem as prevalent as that towards the hepatitis B vaccine.

Cost-effectiveness analysis of changing from live oral poliovirus vaccine to inactivated poliovirus vaccine in Australia.

Estimate the economic impact of introducing inactivated poliovirus vaccine (IPV) into the Australian childhood immunisation schedule to eliminate vaccine-associated paralytic poliomyelitis (VAPP). Cost-effectiveness of two different four-dose IPV schedules (monovalent vaccine and IPV-containing combination vaccine) compared with the current four-dose oral poliovirus vaccine (OPV) schedule for Australian children through age six years. Model used estimates of VAPP incidence, costs, and vaccine utilisation and price obtained from published and unpublished sources. Main outcome measures were total costs, outcomes prevented, and incremental cost-effectiveness, expressed as net cost per case of VAPP prevented. Changing to an IPV-based schedule would prevent 0.395 VAPP cases annually. At $20 per dose for monovalent vaccine and $14 per dose for the IPV component in a combination vaccine, the change would incur incremental, annual costs of $19.5 million ($49.3 million per VAPP case prevented) and $6.7 million ($17.0 million per VAPP case prevented), respectively. Threshold analysis identified break-even prices per dose of $1 for monovalent and $7 for combination vaccines. Introducing IPV into the Australian childhood immunisation schedule is not likely to be cost-effective unless it comes in a combined vaccine with the IPV-component price below $10. More precise estimates of VAPP incidence in Australia and IPV price are needed. However, poor cost-effectiveness will make the decision about switching from OPV to IPV in the childhood schedule difficult.

Cost-effectiveness analysis of changing from live oral poliovirus vaccine to inactivated poliovirus vaccine in Australia

Cost-effectiveness analysis of changing from live oral poliovirus vaccine to inactivated poliovirus vaccine in Australia

Should programmes for community-level meningococcal vaccination be considered in Australia? An economic evaluation.

Disease due to serogroup C Neisseria meningitidis is life-threatening and potentially preventable by vaccination. In 1999, the UK instigated mass vaccination after a sustained increase in serogroup C meningococcal disease. In the same year, Victoria, Australia experienced a similar change in disease epidemiology. It is timely to undertake an economic evaluation of options for community vaccination in Australia based on local data. Cost-effectiveness and cost-benefit analyses of three options for use of polysaccharide vaccine were undertaken for a hypothetical population aged 15--19 years. Baseline analyses assumed 5 years' duration of vaccine protection following a single year of programme implementation. Sensitivity analyses of key variables were performed, including vaccine coverage and effectiveness, case fatality rate and the discount rate. Outcomes included the number of people vaccinated, cases averted, life-years saved and disability-adjusted life-years (DALY) averted. Cost-benefit analysis used lost earnings avoided as a measure of vaccination benefit. Vaccination of people aged 15--19 years in a defined population with a high rate of disease was the most cost-effective option. Compared with no vaccination and assuming 5 years' duration of protection and exclusion of direct cost savings, this resulted in a discounted cost per life-year saved of $23,623, a cost per DALY avoided of $21,097 and benefits exceeding costs in discounted terms. The 'break-even' incidence rate for this option with exclusion of direct cost savings was 14.0/100,000. Community use of polysaccharide vaccination may be cost effective in Australia under certain conditions. Economic evidence favours use of vaccination in well-defined populations with a high rate of disease. Policy decision-making also requires consideration of non-economic factors, including feasibility of implementation and risk perception by the community.

A short history of vaccination in Australia.

It is almost 50 years since infant vaccination for diphtheria, pertussis and tetanus became routine in Australia. Since then, the incidence of vaccine-preventable diseases has declined dramatically. We have used existing records and the recollections of experts to compile a history of vaccination in Australia, focusing on vaccines in the current childhood schedule.

Efficacy and effectiveness of pneumococcal polysaccharide vaccines and their use in industrialised countries.

Use of pneumococcal polysaccharide vaccines remains controversial, even though clinical trials have shown their efficacy in preventing invasive disease caused by vaccine serotypes in immunocompetent adults. Retrospective studies indicate these vaccines have about 50%-80% effectiveness for preventing invasive disease caused by vaccine serotypes, although effectiveness wanes over time and with age. The elderly, people living in institutions and those with chronic cardiac or respiratory disease, alcoholism or diabetes mellitus who are in relatively good health would benefit from vaccination; a polysaccharide vaccine program in the elderly has been shown to be cost-effective. In young children, polysaccharide vaccine should be evaluated as a booster to conjugate pneumococcal vaccines, which are likely to be available soon in industrialised countries. In view of the high rates of hospitalisation and of antimicrobial resistance in pneumococci, every effort should be made to increase coverage by pneumococcal polysaccharide vaccine in Australia, according to guidelines of the National Health and Medical Research Council.

Cost effectiveness of rotavirus vaccination in Australia

Rotavirus gastroenteritis causes substantial morbidity, including hospital admission, in young children. In the context of recent vaccine developments, this study aimed to estimate the cost-effectiveness of a rotavirus vaccination program in Australia. Standard methods of health economic evaluation were used to assess the total cost of rotavirus immunisation (as the difference between estimated vaccination program costs and the cost of disease that would be avoided by immunisation) and relate this to the number of cases of disease that would be prevented. Estimates were made from both societal and health care systems perspectives. Based on Australian data on disease incidence and cost of hospitalisation, the current annual cost of rotavirus disease is about $26.0 million. Using conservative vaccine efficacy estimates, current immunization uptake rates and a cost of $30 per dose of vaccine, rotavirus immunisation would incur a net societal cost of $2.9 million ($11 per child), at a gross program cost of $21.6 million. These estimates are sensitive to two sources of uncertainty in the estimation of program delivery costs: vaccine price and whether separate immunization visits would be required. A rotavirus immunisation program would be cost-neutral to Australian society at a vaccine price of $26 per dose (or $19 when health care system costs only are considered). Rotavirus immunization may be cost-effective in Australia, but considerable uncertainty remains. Policy decisions will depend heavily on pricing of the vaccine and may also need to consider intangible costs not accounted for in this analysis.

Field isolates of fowlpox virus contaminated with reticuloendotheliosis virus

The polymerase chain reaction (PCR) method was used to examine samples from field cases of fowlpox for the presence of reticuloendotheliosis virus (REV). The S‐strain fowlpox vaccine, known to be contaminated with REV, served as a positive control. Fowlpox virus was grown from field samples and vaccines by inoculation of embryonated hen eggs by the chorioallantoic membrane (CAM) route. DNA was extracted from the CAM lesions and examined for REV proviral sequences using primers specific for the long terminal repeats of REV. Amplicons of the expected length were detected in all the 45 field samples from poultry and in the S strain vaccine. Two other vaccines and two isolates from wild birds contained no detectable REV sequences. The PCR products from the vaccine and one field isolate were sequenced and were identical. These products showed 81 to 87.5% homology with the published sequences for the long terminal repeats of REV. It was not determined whether the REV proviral DNA was integrated with cellular DNA, fowlpox DNA or both. Inoculation of day‐old chickens with the S‐strain vaccine resulted not only in the production of fowlpox lesions but also feathering defects and proventriculitis. This suggests that the REV present in the vaccine is replication competent. Problems being encountered with protection from fowlpox following vaccination in Australia might be attributed to simultaneous challenge with fowlpox virus and REV.

Models used in Australia in risk assessments for veterinary biologicals.

In Australia, the development of models for risk assessment in the field of veterinary biologicals is based on the chapter on "Import risk analysis' in the Office International des Epizooties International Animal Health Code. The development process involves examination of the following: country factor (source of the product), commodity factor, nature of the product, potential to carry contaminating organisms, end-use, risk reduction features of the manufacture or nature of the product (e.g. inactivation or extraction techniques, dilution). Finally, the Australian risk model and quarantine process carefully examine the risk of domestic exposure. Consideration goes beyond potential in vivo or in vitro use of the product and encompasses the wider potential for access to animals (domestic and farm, native and feral) after arrival in Australia. Practice involves the limitation of certain agents to appropriate biocontainment facilities, or--where therapeutic or immunotherapeutic use is planned--continuous assessment of the production systems of the manufacturing company. These assessments are developed into templates or precedents which may be re-used to lend consistency and security to the manufacturing process. Australian practice and assessment recognise the wide variety of biologicals and the number of diseases which they can potentially introduce. The author examines several types of biologicals and emerging threats, including that presented by bovine spongiform encephalopathy. This paper complements the paper by J. Owusu in this issue of the Scientific and Technical Review, which addresses, in particular, the assessment of vaccines in Australia. The National Registration Authority plays a specific role which is complementary to that of the other quarantine authorities. Attitudes to risk assessment in Australia derive from the freedom of this country from many diseases, from the potential for inoculation of imported biologicals into animals with direct transmission of contaminants, and from the difficulty of identifying the original source country in many cases (due to the freedom of movement of many biologicals, particularly the substrates of many immunobiologicals).

Adaptation to environment--the Pasteur anthrax vaccine in Australia.

Australian Veterinary JournalVolume 69, Issue 12 p. 318-321 Adaptation to environment—the Pasteur anthrax vaccine in Australia JH TODD, JH TODD 6 Balowrie Street, Yowie Bay, New South Wales 2228Search for more papers by this author JH TODD, JH TODD 6 Balowrie Street, Yowie Bay, New South Wales 2228Search for more papers by this author First published: December 1992 https://doi.org/10.1111/j.1751-0813.1992.tb09913.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume69, Issue12December 1992Pages 318-321 RelatedInformation

Investigations of breakdowns in protection provided by living Babesia bovis vaccine

Field investigations of protection afforded by live Babesia bovis vaccine in Australia revealed that a ninefold increase in vaccine failures occured in the period from 1985 to 1990. Laboratory trials using 189 experimental cattle were conducted to evaluate the protection afforded by the Babesia bovis strain used in the commercial vaccine during this time. Four isolates from clinical cases of babesiosis in vaccinated cattle were assessed. The results showed that the strain used in the vaccine during the 5 year period was poorly protective against three isolates while a recently isolated and prepared vaccine strain was strongly protective. Circumstantial evidence is provided that indicates the vaccine failures were due to change in the field populations of Babesia bovis, rather than change in the strain used in the vaccine. Implications of the results for the future of Babesia bovis vaccines are discussed.

Optimal age for measles and mumps vaccination in Australia

Trivalent measles-mumps-rubella vaccine has recently replaced measles-mumps vaccine in Australia and is recommended as a single dose at the age of 12 to 15 months, with the exception of Aboriginal children in central Australia who are vaccinated at 9 months. The timing of measles vaccination has been controversial not only in Australia but also in the United States, where measles outbreaks continue to occur. This study aimed to determine seroconversion rates for measles-mumps vaccine in children aged 12 to 18 months and to make a recommendation for the timing of vaccination based on seroconversion rates and attack rates. The parents of 425 children aged 12 to 18 months gave consent for their children to have serum collected at the time of measles-mumps vaccination and three months later. The mean age at vaccination of the children who had two serum samples for measles and mumps antibody estimations was 13.9 months (mode, 13.1). The seroconversion rate for measles was 95% (314/329) (95% confidence interval (CI), 92.5% to 97.3%) and for mumps 97% (309/320) (95% CI, 93.8% to 98.1%). There were no statistically significant differences in the rates of seroconversion for measles or mumps related to age in months at the time of vaccination or in post-vaccination measles antibody titres related to age at vaccination. Post-vaccination mumps antibody titres tended to be lower in older vaccinees. None of the children who presented for vaccination had serological evidence of prior measles infection but five had evidence suggestive of prior mumps. As the seroconversion rates for measles and mumps vaccines were very high in these children it was concluded that no advantage resulted from delaying vaccination until 15 months and that the current National Health and Medical Research Council recommendations for vaccination at age 12 to 15 months should remain.

FROM PARIS TO NARRANDERA: ADAPTATION IN THE DIFFUSION OF ANTHRAX VACCINATION IN THE AUSTRALIAN PASTORAL INDUSTRY

In 1881 Louis Pasteur demonstrated to an incredulous world the efficacy of his vaccine for the prevention of the fatal disease anthrax in sheep and cattle. A decade later Pasteur's nephew and assistant, Adrien Loir, was manufacturing the vaccine in Sydney. But although Loir's operations were begun at the behest of local pastoralists, the diffusion of the Pasteur vaccine was not very successful in Australia. Within a few years it was virtually displaced from the market by the modified vaccine produced by two Australian men, John Alexander Gunn and John McGarvie Smith. The process of transfer and diffusion involved in that displacement is the concern of this paper. In particular, it highlights the importance of local adaptation for the successful diffusion of anthrax vaccination in Australia.

Influenza vaccination in Australia: a review of the economic evidence for policy recommendations.

The National Health and Medical Research Council recommends that persons who are believed to be at a higher risk of the complications and of dying of influenza should receive annual vaccinations against the disease. The Council refers specifically to persons who are over the age of 65 years and to those with chronic medical conditions. Recommendations such as these place demands on scarce health resources and it is important to determine if such policies result in the efficient utilization of resources. Accordingly, this article reviews the evidence on the economic efficiency of different vaccination strategies. Two major conclusions emerge. First, even allowing for variability in vaccine effectiveness due to viral antigenic drift, influenza-vaccination programmes, in general, are more cost-effective than are many other interventions that are undertaken as a routine in Australia. Secondly, vaccinating healthy persons who are 45 years of age to 64 years of age is more cost-effective than is vaccinating persons in some of the high-risk groups. Thus, there is likely to be a case for reconsidering whether healthy persons who are younger than 65 years of age also should be included in the official recommendations.