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Peter B McIntyre

Publications and source records attributed to Peter B McIntyre.

29 records · Page 2Linked to original sources
PubMed2004

What do we know about 7vPCV coverage in Aboriginal and Torres Strait Islander children?

In 2001, a publicly funded pneumococcal conjugate vaccine (7vPCV) program commenced for Aboriginal and Torres Strait Islander children aged under two years. At present, there is very little knowledge about the uptake of 7vPCV vaccine amongst Aboriginal and Torres Strait Islander children. This study examined the rollout and use of 7vPCV vaccine in Australia and estimated immunisation coverage for Indigenous children at the age of 12 months for 7vPCV vaccine. To calculate 7vPCV coverage we chose four consecutive 3-month birth cohorts born between 1 October 2001 and 30 September 2002. The immunisation status of children in each birth cohort was assessed at 12 months for the third dose of 7vPCV vaccine. The largest absolute number of 7vPCV doses was given in Queensland, the Northern Territory and New South Wales. As the 7vPCV program matured, a progressively higher proportion of total doses was administered to children under the age of 12 months consistent with the introduction of the program. For all jurisdictions except the Northern Territory and Western Australia, where it has remained reasonably constant, estimated coverage increased over the most recent birth cohorts but was still less than 50 per cent for all states except the Northern Territory, Queensland, and Western Australia. This study provides the first national measure of 7vPCV immunisation coverage among Indigenous children in Australia. With the likely improvement over time in the recording of 7vPCV vaccinations and Indigenous status on the Australian Childhood Immunisation Register, the validity of coverage estimates is likely to increase.

Attitude to Health↗
PubMed2004

Reasons for incomplete immunisation among Australian children. A national survey of parents.

BACKGROUND: Incomplete immunisation among Australian children may be due to parents disagreeing with immunisation rather than medical contraindications or access issues. SETTING AND METHODS: The parents of 1338 children recorded on the ACIR as incompletely immunised were telephoned and interviewed. RESULTS: Of the 462 parents who confirmed their child was incompletely immunised, 270 (58%) disagreed with or were concerned about immunisation; 190 (70%) of these were concerned about vaccine side effects. The disagreeing 270 parents were significantly more likely to be highly educated and have a child with no vaccinations recorded on the ACIR. No vaccinations were recorded on the ACIR for 81% of children of both these parents, and of parents registered as conscientious objectors to immunisation. Together these two groups accounts for 2.5-3.0% of the annual birth cohort. DISCUSSION: In order to achieve the 95% immunisation rates necessary for disease control, tailored approaches to promote immunisation among parents are required.

Australia↗
PubMed2003

Effectiveness of pertussis vaccination in New South Wales, Australia, 1996-1998.

Pertussis notifications have increased over the past decade in Australia and other industrialised countries. This study estimates the effectiveness of pertussis vaccination in one Australian State (New South Wales, NSW) among children aged less than 14 years, during a period when an Australian whole-cell pertussis vaccine was in routine use. Cases notified with pertussis between 1996 and 1998 and pertussis vaccine coverage estimates from the Australian Childhood Immunisation Register were used. Vaccine effectiveness (VE) was calculated using the screening method, with adjustment for age group, year of disease onset and area of residence. VE was highest (91%) in the youngest age group (8-23 months) and lowest (78%) in the oldest age group (9-13 years). Pertussis vaccination is highly effective at preventing pertussis in NSW children, as measured by notified cases. Ongoing monitoring will be important to evaluate VE following Australia's change to an acellular vaccine based program.

Adolescent↗
PubMed2003

Effect of the preschool pertussis booster on national notifications of disease in Australia.

BACKGROUND: Australia introduced a fifth dose of pertussis vaccine at 4 to 5 years of age in 1994, the first country to do so for some 40 years. We report trends in national pertussis notifications from 1993 to 2001. METHODS: Notified pertussis cases were analyzed by age and year of disease onset. RESULTS: Before the fifth dose was introduced, notification rates were higher among 5- to 9-year-olds than 10- to 14-year-olds (76 per 100 000 population vs.65 per 100 000). As more 5- to 9-year-olds became eligible for the fifth dose, their notification rates as a group and by year of age progressively fell to below those of 10- to 14-year-olds, consistent with a vaccine effect. Comparison of notification rates for the epidemic years of 1997 and 2001 shows that 5- to 10-year-olds (eligible for fifth dose) had lower notification rates in 2001 (61 per 100 000) than 5- to 10-year-olds in 1997 (196 per 100 000). This contrasts with children who were not eligible for the fifth dose (12- to 14-year-olds), who had higher notification rates in 2001 (223 per 100 000) than 12- to 14-year-olds in 1997 (160 per 100 000). CONCLUSIONS: The pattern of age-specific notification rates provides strong evidence that the fifth dose reduced the incidence of pertussis in older children. It will be important to track the impact of the fifth dose on adolescent pertussis notifications to assess the duration of vaccine-acquired immunity.

Adolescent↗
PubMed2003

Measles vaccination coverage among five-year-old children: implications for disease elimination in Australia.

OBJECTIVES: To (i) assess under-reporting of measles-mumps-rubella (MMR) vaccinations to the Australian Childhood Immunisation Register (ACIR); (ii) estimate MMR coverage among five-year-old children and the proportion immune to measles infection; (iii) identify factors related to non-uptake of MMR vaccination. METHODS: We analysed ACIR data for a birth cohort of approximately 64,000 children aged five years. The parents of a sample of 506 children with no ACIR record for the second MMR vaccination (MMR2), due at four years of age, were interviewed by telephone to assess under-reporting to the ACIR and reasons for non-uptake of MMR vaccination. RESULTS: Parents reported that 22% (n = 111) of the surveyed 506 children had received MMR2 before their fifth birthday, and 42% (n = 214) by approximately 5.5 years of age. After correcting for this level of under-reporting to the ACIR, MMR2 coverage for the entire cohort at five years of age was 52.9% (95% CI 52.3-53.4), and increased to 84.1% (95% CI 83.4-84.8) by approximately 5.5 years of age. This was 4.3% and 8.2%, respectively, higher than ACIR coverage estimates at the two ages. Based on the corrected MMR coverage estimates, 93% of the cohort was immune to measles due to vaccination. The most common parent-reported reason for incomplete vaccination was lack of knowledge about the MMR vaccination schedule. CONCLUSIONS: Measles elimination in Australia will require continued effort in vaccination coverage and timeliness among pre-school children. School-entry requirements are important for MMR2 uptake. Strategies are needed to improve reporting to the ACIR for more accurate measurement of coverage.

Attitude to Health↗
PubMed2003

Immunisation coverage in Australia corrected for under-reporting to the Australian Childhood Immunisation Register.

OBJECTIVE: To assess the level of under-reporting to the Australian Childhood Immunisation Register (ACIR) and the resulting underestimation of national immunisation coverage using ACIR data, and to correct national immunisation estimates for under-reporting. METHODS: A national population-based telephone survey was conducted in May-July 2001 of two random samples of children born in 1998 and 1999 who were recorded on the ACIR as incompletely immunised at either 12 months or 24 months of age. Parents were asked whether and when their child had received the vaccinations required to qualify as fully immunised. Survey data were then used to correct ACIR-derived coverage estimates at 12 and 24 months of age. RESULTS: Of 640 surveyed children in the 12-month group, 258 (40%) met the study definition of 'definitely immunised'. This adjusted the ACIR coverage estimate upwards by 2.7% to 94% (95% CI 93.6-94.1). Of 698 surveyed children in the 24-month group, 387 (55%) met the study definition of 'definitely immunised' at the second birthday. Adjusted coverage for doses due by 24 months was 89.8% (95% CI 89.6-90.1), 5% higher than recorded on the ACIR. CONCLUSIONS: Immunisation coverage in Australia for all scheduled vaccines due by 12 months of age is 94% and for all vaccines due by two years of age is almost 90%. The ACIR underestimates coverage by up to 5%. As the ACIR database relies on provider notification, published estimates of immunisation coverage are unlikely to rise significantly above current levels, unless mechanisms are put in place to further improve notification to the ACIR.

Australia↗
PubMed2003

Estimating immunisation coverage: is the 'third dose assumption' still valid?

Immunisation coverage is calculated from Australian Childhood Immunisation Register (ACIR) data using the 'third dose assumption'. This assumes that if the third in a series of vaccine doses has been recorded on the ACIR, the previous two doses have been received, whether or not they are recorded. The objectives of this study were to validate the 'third dose assumption', and measure the impact of the assumption on immunisation coverage estimates at 12 months of age. A sample of children born in 1999 and assessed as fully immunised at 12 months of age by applying the 'third dose assumption' were selected from the ACIR. Parents were interviewed by telephone to obtain information about vaccinations not recorded on the ACIR. Based on the survey results, the impact of the 'third-dose assumption' on national coverage estimates at 12 months of age was estimated. Of 219 surveyed children assessed as up-to-date at 12 months of age only by applying the 'third dose assumption', 212 (96.8%) met study criteria of 'definite' immunisation for all unrecorded first and second vaccine doses. Of the remaining seven, six believed all doses had been received, while one confirmed that one dose had been missed. The 'third dose assumption' overestimated coverage by 0.2 per cent, based on criteria for 'definite' immunisation. If the assumption were not used, immunisation coverage at 12 months of age in Australia would have been underestimated by 7 per cent. The 'third dose assumption' is valid and important to use in calculating immunisation coverage from the ACIR. Although ACIR reporting and coverage levels continue to improve, under-reporting of vaccine doses due at two and four months of age persists. The 'third dose assumption' may be applicable to comparable immunisation registries in other countries.

Australia↗
PubMed2003

Is low immunisation coverage in inner urban areas of Australia due to low uptake or poor notification?

INTRODUCTION: The Australian Childhood Immunisation Register (ACIR) consistently reveals pockets of lower immunisation coverage in inner urban areas. We investigated whether low uptake or poor notification of immunisation is the main reason for this difference. METHODS: We estimated under reporting by telephone surveying the parents of 640 children recorded as incompletely immunised on the ACIR at 12 months of age. Immunisation status was based on parental report of written records and/or date of receipt. RESULTS: Of the 97 children living in inner urban areas (defined by postcode and population density), 55 (57%) were shown to be 'definitely immunised'. One hundred and thirty-four (53%) of the 253 children in other urban areas were shown to be 'definitely immunised'. Both these groups were significantly more likely to be 'definitely immunised' than the 104 (36%) of 290 children in areas outside capital cities (p < 0.0001). DISCUSSION: Apparent lower immunisation uptake in inner urban areas of Australia may be attributable to reporting error.

Australia↗
PubMed2002

Observational methods in epidemiologic assessment of vaccine effectiveness.

Observational methods are important in the measurement of vaccine effectiveness (VE) as experimental designs cannot be used for measurement of vaccines already on the vaccination schedule. Furthermore, efficacy measured in clinical trials under ideal conditions may differ to effectiveness in the field under non-ideal conditions and in different populations. In addition to post-licensure surveillance, observational VE studies are particularly important when disease incidence does not predictably decrease with increased vaccine coverage, when high proportions of vaccine failure among reported cases suggest a problem with the vaccine or when issues arise that were not predicted in pre-licensure evaluations. Commonly used study types for evaluating VE include cohort studies, household contact studies, case-control studies, the screening method and case-cohort studies. There are many potential biases in all observational VE studies which should be considered in the study design and analysis stage. Of the five observational study types reviewed, cohort studies undertaken during an outbreak investigation offer the simplest means of VE estimation and is the preferred study design where the situation permits. Where this is not possible the screening method is the most economical and rapid method. It is essential that the effectiveness of all vaccination programs be evaluated. As new vaccines are introduced to the schedule, booster doses are added and the timing of doses changed, the role of observational methods in the evaluation of VE will become even more important. To date, few observational VE studies have been undertaken in Australia, suggesting the under-utilisation of these methods.

Case-Control Studies↗
PubMed2002

Using the Australian Childhood Immunisation Register to track the transition from whole-cell to acellular pertussis vaccines.

From 1997 to 1999, Australia changed from a whole-cell based pertussis vaccination program to an acellular one. This paper tracks the transition from whole-cell to acellular pertussis vaccines by calculating the number of whole cell (DTPw) and acellular (DTPa) pertussis vaccines recorded on the Australian Childhood Immunisation Register (ACIR) each month from January 1996 to August 2000. The number of combined diphtheria-tetanus (CDT) vaccines, recommended where DTP is contraindicated and for the fifth dose prior to 1994, was also calculated. The use of DTPa increased following its licensing in 1997, with a corresponding decrease in the use of DTPw. The increase was initially greatest in its use as a fourth and fifth dose, for which it was funded at a national level in 1997. Subsequently, a steep increase in its use for the first three doses followed in 1999, coinciding with it becoming free of charge for infants nationally. The use of CDT has decreased markedly since January 1996 and, since March 2000, fewer than 100 CDT vaccines per month were recorded on the ACIR, suggesting that this vaccine is not being inappropriately used.

Australia↗