Biomedical subjects

Brynley P Hull

Publications and source records attributed to Brynley P Hull.

12 recordsLinked to original sources

PubMed2006

Timeliness of childhood immunisation in Australia.

There are few data, especially outside the United States, examining the timeliness of childhood vaccination, although it is of key importance for diseases such as pertussis, and invasive disease due to Haemophilus influenzae type b and Streptococcus pneumoniae. The aim of this study was to use the unique resource of the Australian Childhood Immunisation Register (ACIR) to examine trends in and factors associated with timeliness of infant vaccination at the national level. As in previous studies, age-appropriate immunisation was defined as within 30 days of the recommended age. Vaccination delays became more common for later doses, given at an older age, but long delay (greater than 6 months) occurred in only 1-2%. Although immunisation coverage increased over time, timeliness did not improve. Among Indigenous infants, long delays occurred in 5-12% of those residing in very remote areas, but by 2 years of age, overall immunisation coverage was similar to non-Indigenous children. With immunisation coverage at the key indicator ages of 12 and 24 months now high in most industrialised countries including Australia, timeliness of vaccine doses should be the next benchmark to aim for in program performance, especially in specific sub-groups such as Indigenous children who stand to gain most from prevention of early onset disease.

Australia↗

PubMed2006

Australia's notifiable diseases status, 2004, annual report of the National Notifiable Diseases Surveillance System.

In 2004, 60 diseases and conditions were nationally notifiable in Australia. States and Territories reported a total of 110,929 cases of communicable diseases to the National Notifiable Diseases Surveillance System (NNDSS): an increase of 4 per cent on the number of notifications in 2003. In 2004, the most frequently notified diseases were sexually transmissible infections (46,762 cases; 42% of total notifications), gastrointestinal diseases (25,247 cases; 23% of total notifications) and bloodborne diseases (19,191 cases; 17% of total notifications). There were 13,206 notifications of vaccine preventable diseases, 6,000 notifications of vectorborne diseases, 1,799 notifications of other bacterial infections (includes, legionellosis, leprosy, meningococcal infections and tuberculosis) and 877 notifications of zoonotic diseases.

Adolescent↗

PubMed2005

Probability of coincident vaccination in the 24 or 48 hours preceding sudden infant death syndrome death in Australia.

OBJECTIVE: Vaccination does not cause sudden infant death syndrome (SIDS). However, SIDS peaks at 2 months of age, when vaccination encounters are frequent. There are no published estimates using population data on age of death and immunization coverage to indicate to practitioners how often coincident vaccination may occur by chance. This study aimed to determine the probability that an Australian infant who has died of SIDS was vaccinated in the days before death. METHODS: An analytical study of population death data and immunization coverage was conducted for Australian children who were born between April 1, 2002, and March 31, 2003. Also evaluated were Australian children who were registered as dying of SIDS between 1997 and 2001. The main outcomes measured were distribution of SIDS deaths by age and distribution of immunization coverage by age. RESULTS: The probability of recent vaccination and SIDS coinciding varied by age and day of the week of death. The overall estimated probability of vaccination within the last 24 hours for a child who has died of SIDS in Australia is estimated as 1.3%. In the last 48 hours, it is 2.6%. With the average number of SIDS deaths for the period 1997-2001 equal to 130 cases per year, we estimated that a case of SIDS will occur when vaccination was given in the last 24 hours in 1.7 cases per year and within 48 hours in 3.5 cases. CONCLUSIONS: Although coincident vaccination and SIDS should not be a frequent problem, it can be expected to occur at least annually in Australia by chance alone. The probabilities of vaccination by age estimated in this study can also be applied to estimate the probability of a vaccination encounter for children who have experienced any unusual medical condition or death, when these occurrences are known to be unrelated to vaccination.

Age Factors↗

PubMed2004

Effectiveness of the linkage of child care and maternity payments to childhood immunisation.

In 1998, Australia enacted comprehensive national legislation making receipt of the maternity immunisation allowance (MIA) and the child care benefit (CCB) conditional on evidence of age-appropriate immunisation. We assessed the impact of this policy on immunisation status using a nationally representative population-based case-control study of 589 fully immunised controls and 190 incompletely immunised cases, aged 28-31 months. Immunisation status was significantly associated with parent awareness of the MIA (adjusted odds ratio (aOR) = 3.34, 95% CI = 2.28 - 4.91) and CCB (aOR = 2.08, 95% CI = 1.30 - 3.34). Only 31% of the 219 control parents who were receiving the CCB reported that they could continue to afford child care without the assistance of the CCB. The use of legislated financial immunisation incentives for parents appears to be widely accepted among Australian parents and to have had an impact on immunisation uptake. The policy may serve as a model for other comparable countries.

Australia↗

PubMed2004

Evaluation of immunisation coverage for aboriginal and Torres Strait Islander children using the Australian Childhood Immunisation Register.

OBJECTIVE: To estimate immunisation coverage for routinely administered vaccines among children using receipt of a particular Hib vaccine (PRP-OMP) as a proxy for Indigenous status. METHODS: Until May 2000, PRP-OMP was provided only for Indigenous children in all jurisdictions except the Northern Territory. In three one-year ACIR-derived birth cohorts, any child recorded on the ACIR as receiving one or more doses of PRP-OMP as the only Hib vaccine was presumed to be Aboriginal and Torres Strait Islander. Using this proxy, estimated numbers of Indigenous children were compared with Australian Bureau of Statistics estimates, and immunisation status for recommended vaccines was estimated at 12 and 24 months by jurisdiction and remoteness compared with children who received other Hib vaccines (presumed non-Indigenous). RESULTS: The numbers of Aboriginal and Torres Strait Islander children estimated using this 'proxy method' are approximately 42% of those estimated by the ABS. Immunisation coverage (among proxy Indigenous children) at 12 months (72-76%) and 24 months (64-73%) was considerably lower than others (90-94% and 81-88%, respectively). These children had significantly lower coverage when living in accessible areas than remote areas. CONCLUSIONS AND IMPLICATIONS: These data provide the first national measure of immunisation status and are likely to be a valid measure among those identified. Aboriginal and Torres Strait Islander immunisation coverage is 17% lower with the biggest gaps in urban areas, indicating the need for better quality data informing appropriate interventions.

Australia↗

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

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

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↗