Anaphylaxis following quadrivalent human papillomavirus vaccination

BACKGROUND

In 2007, Australia implemented the National human papillomavirus (HPV) Vaccination Program, which provides quadrivalent HPV vaccine free to all women aged 12-26 years. Following notification of 7 presumptive cases of anaphylaxis in the state of New South Wales, Australia, we verified cases and compared the incidence of anaphylaxis following HPV vaccination to other vaccines in comparable settings.

METHODS

We contacted all patients with suspected anaphylaxis and obtained detailed histories from telephone interviews and a review of medical records. A multidisciplinary team determined whether each suspected case met the standardized Brighton definition. Some participants also received skin-prick allergy testing for common antigens and components of the HPV vaccine.

RESULTS

Of 12 suspected cases, 8 were classified as anaphylaxis. Of these, 4 participants had negative skin-prick test results for intradermal Gardasil. From the 269 680 HPV vaccine doses administered in schools, 7 cases of anaphylaxis were identified, which represents an incidence rate of 2.6 per 100 000 doses (95% CI 1.0-5.3 per 100 000). In comparison, the rate of identified anaphylaxis was 0.1 per 100 000 doses (95% CI 0.003-0.7) for conjugated meningococcal C vaccination in a 2003 school-based program.

INTERPRETATION

Based on the number of confirmed cases, the estimated rate of anaphylaxis following quadrivalent HPV vaccine was significantly higher than identified in comparable school-based delivery of other vaccines. However, overall rates were very low and managed appropriately with no serious sequelae.

Evaluating the potential effectiveness of compensatory mitigation strategies for marine bycatch

Conservationists are continually seeking new strategies to reverse population declines and safeguard against species extinctions. Here we evaluate the potential efficacy of a recently proposed approach to offset a major anthropogenic threat to many marine vertebrates: incidental bycatch in commercial fisheries operations. This new approach, compensatory mitigation for marine bycatch (CMMB), is conceived as a way to replace or reduce mandated restrictions on fishing activities with compensatory activities (e.g., removal of introduced predators from islands) funded by levies placed on fishers. While efforts are underway to bring CMMB into policy discussions, to date there has not been a detailed evaluation of CMMB's potential as a conservation tool, and in particular, a list of necessary and sufficient criteria that CMMB must meet to be an effective conservation strategy. Here we present a list of criteria to assess CMMB that are tied to critical ecological aspects of the species targeted for conservation, the range of possible mitigation activities, and the multi-species impact of fisheries bycatch. We conclude that, overall, CMMB has little potential for benefit and a substantial potential for harm if implemented to solve most fisheries bycatch problems. In particular, CMMB is likely to be effective only when applied to short-lived and highly-fecund species (not the characteristics of most bycatch-impacted species) and to fisheries that take few non-target species, and especially few non-seabird species (not the characteristics of most fisheries). Thus, CMMB appears to have limited application and should only be implemented after rigorous appraisal on a case-specific basis; otherwise it has the potential to accelerate declines of marine species currently threatened by fisheries bycatch.

What do we know about 7vPCV coverage in Aboriginal and Torres Strait Islander children? A 2007 update

In 2001, a publicly funded 7 valent pneumococcal conjugate vaccine (7vPCV) program commenced for Aboriginal and Torres Strait Islander children aged less than 2 years. This study updates early estimates of 7vPCV coverage in Aboriginal and Torres Strait Islander children using Australian Childhood Immunisation Register data between 31 December 2004 and 30 September 2007. We chose four 3-month birth cohorts of children and assessed their immunisation status at 12 months of age for pneumococcal conjugate vaccine and for 'fully immunised'. After the introduction of universal childhood conjugate pneumococcal vaccination in 2005, 7vPCV coverage increased substantially among Aboriginal and Torres Strait Islander children nationally, and in all jurisdictions but remained lower than among non-Indigenous children. The results re-emphasise the greater impact of universal, compared with targeted, programs on vaccine coverage among Indigenous children.

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.

Annual report on surveillance of adverse events following immunisation in Australia, 2006

This report summarises Australian passive surveillance data for adverse events following immunisation (AEFI) reported to the Adverse Drug Reactions Advisory Committee for 2006, and describes reporting trends over the seven-year period 2000 to 2006. There were 779 AEFI records for vaccines administered in 2006. This is an annual AEFI reporting rate of 3.8 per 100,000 population, the lowest since 2002 and a 10% decrease compared with 2005 (869 AEFI records; 4.3 records per 100,000 population). Dose-based AEFI reporting rates in 2006 were 1.9 per 100,000 doses of influenza vaccine for adults aged > or = 18 years, 19.1 per 100,000 doses of pneumococcal polysaccharide vaccine for those aged > or = 65 years and 12.5 per 100,000 doses of scheduled vaccines for children aged < 7 years. Trend data showed transient increases in reporting of AEFI following the introduction of DTPa-IPV combination vaccines in November 2005 for children aged < 7 years. The majority of the 779 AEFI records for 2006 described non-serious events while 11% (n = 85) described AEFIs defined as serious. There was one report of death temporally associated with receipt of dTpa-IPV and typhoid vaccines in an adult with a history of a chronic medical condition. The most frequently reported individual AEFI was injection site reaction in children following a fourth or fifth dose of acellular pertussis-containing vaccine (70 reports per 100,000 doses). The data confirm the low rate of AEFI reported in Australia and demonstrate the ability of the system to detect and investigate signals such as those associated with changes in immunisation programs.

The impact of a new universal infant and school-based adolescent hepatitis B vaccination program in Australia

We compared the results of two national serosurveys in Australia to evaluate the impact of universal infant vaccination and school-based programs for adolescents. Immunity improved significantly overall, especially in 1-year-olds (40.0% versus 86%; p<0.0001); in adolescents it was significantly higher in regions with established school-based programs (56.6% versus 38.8%; p=0.0008). 6.1% of 1-59-year-olds were positive for HBcAb and 0.7% for HBsAg. We have demonstrated successful implementation of universal infant hepatitis B vaccination in Australia and that school-based programs for adolescents are effective. This experience should be applicable to low prevalence countries in northern Europe which have not implemented universal hepatitis B immunisation.

Pertussis epidemiology in Australia over the decade 1995-2005--trends by region and age group

Important changes have occurred in the National Immunisation Program for pertussis during the decade 1995-2005, including the introduction of acellular pertussis vaccine for all doses, removal from the schedule of the booster dose at 18 months, and the introduction of a booster dose for adolescents. In addition, the coverage of pertussis vaccine at 12 and 24 months has substantially increased as recorded by Australian Bureau of Statistics surveys and the Australian Childhood Immunisation Register. There were 75,458 notifications nationally between 1995 and 2005, with little change in the annual number of notifications at the national level but with periodic and dramatic changes in the age distribution of notified cases. Pertussis is well controlled in the 1-4 and 5-9 year age groups, and the highest annual notification rates continue to be in infants under 6 months of age. Adolescents aged 10-19 years had high notification rates in all states and territories, over this period, but 63% of notifications are now in the 20-59 year age range. Following the introduction of a fifth dose for adolescents, the current focus should be on protecting infants too young to be vaccinated and further defining the true morbidity of the disease in the elderly population.

Compliance with three simultaneous vaccinations due at the one visit at 12 months of age in Australia

The introduction of meningococcal C conjugate vaccine (Men C) into the National Immunisation Program Schedule in January 2003 was the first time that 3 simultaneous vaccine injections were recommended for all Australian children. This study aimed to assess the level of simultaneous vaccination at 12 months of age for 4 cohorts of Australian children. The percentage of children with all 3 vaccinations given simultaneously by jurisdiction increased for all states and territories across the 4 study cohorts, however some jurisdictions fared better than others. The percentage of children with all 3 vaccinations given simultaneously varied by the provider type of the Men C vaccine, being lower for general practitioner providers than other providers. Men C vaccine was the vaccine most commonly delayed. The percentage of children who received all 3 vaccinations simultaneously in Australia also varied by indigenous status, with Indigenous children more likely to receive immunisations simultaneously. The study suggests that some children in Australia are at risk of receiving Men C vaccine late, especially children in jurisdictions where general practitioners give the majority of vaccinations.

The functional role of biodiversity in ecosystems: incorporating trophic complexity

Understanding how biodiversity affects functioning of ecosystems requires integrating diversity within trophic levels (horizontal diversity) and across trophic levels (vertical diversity, including food chain length and omnivory). We review theoretical and experimental progress toward this goal. Generally, experiments show that biomass and resource use increase similarly with horizontal diversity of either producers or consumers. Among prey, higher diversity often increases resistance to predation, due to increased probability of including inedible species and reduced efficiency of specialist predators confronted with diverse prey. Among predators, changing diversity can cascade to affect plant biomass, but the strength and sign of this effect depend on the degree of omnivory and prey behaviour. Horizontal and vertical diversity also interact: adding a trophic level can qualitatively change diversity effects at adjacent levels. Multitrophic interactions produce a richer variety of diversity-functioning relationships than the monotonic changes predicted for single trophic levels. This complexity depends on the degree of consumer dietary generalism, trade-offs between competitive ability and resistance to predation, intraguild predation and openness to migration. Although complementarity and selection effects occur in both animals and plants, few studies have conclusively documented the mechanisms mediating diversity effects. Understanding how biodiversity affects functioning of complex ecosystems will benefit from integrating theory and experiments with simulations and network-based approaches.

Epidemiology of severe hepatitis A in Indigenous Australian children

AIMS

To describe the epidemiology of hepatitis A in Indigenous Australian children.

METHODS

Analysis and mapping of national notification and hospitalisation data.

RESULTS

Indigenous Australian children are at far higher risk of clinical hepatitis A than their non-Indigenous counterparts, particularly in the age group 0-4 years. Rates of hospitalisation (15.5 vs. 0.3 per 100,000) and notification (24.4 vs. 1.8 per 100,000) were higher in Indigenous children aged 0-4 years compared with other children in the same age group. In the age group 5-14 years, the rates were 4.4 per 100,000 (Indigenous) versus 0.6 per 100,000 (non-Indigenous) hospitalisations. This excess morbidity falls sharply with age. Rates were the highest in the Northern Territory, South Australia, Western Australia and North Queensland.

CONCLUSIONS

Indigenous children are at risk of hepatitis A, particularly early in life. Mapping shows that rates were the highest in jurisdictions with the largest Indigenous populations. This study presents baseline data against which to measure the success of new hepatitis A vaccination programme for Indigenous Australian children which commenced in 2005.

Sustained measles elimination in Australia and priorities for long term maintenance

We used the 2002 national serosurvey to evaluate a primary care-based young adult vaccination campaign, measure the reproductive number (R) and, together with vaccination coverage estimates, predict R until 2012. The campaign had no impact on immunity in young adults. R was estimated to be 0.69 and predicted to stay well below the epidemic threshold of 1 until at least 2012, indicating that Australia should remain free of endemic measles in the medium term. To maintain elimination in the longer term, the timeliness and coverage of childhood vaccinations must improve and innovative strategies will be required to improve measles immunity among young adults. This experience is likely to apply to developed countries that have achieved or are approaching measles elimination.

Australia's notifiable diseases status, 2005: annual report of the National Notifiable Diseases Surveillance System

In 2005, 60 diseases and conditions were nationally notifiable in Australia. States and territories reported a total of 125,461 cases of communicable diseases to the National Notifiable Diseases Surveillance System: an increase of 10% on the number of notifications in 2004. In 2005, the most frequently notified diseases were sexually transmissible infections (51,557 notifications, 41% of total notifications), gastrointestinal diseases (29,422 notifications, 23%) and bloodborne diseases (19,278 notifications, 15%). There were 17,753 notifications of vaccine preventable diseases; 4,935 notifications of vectorborne diseases; 1,826 notification of other bacterial infections (legionellosis, leprosy, meningococcal infections and tuberculosis) and 687 notifications of zoonotic diseases.

Fish extinctions alter nutrient recycling in tropical freshwaters

There is increasing evidence that species extinctions jeopardize the functioning of ecosystems. Overfishing and other human influences are reducing the diversity and abundance of fish worldwide, but the ecosystem-level consequences of these changes have not been assessed quantitatively. Recycling of nutrients is one important ecosystem process that is directly influenced by fish. Fish species vary widely in the rates at which they excrete nitrogen and phosphorus; thus, altering fish communities could affect nutrient recycling. Here, we use extensive field data on nutrient recycling rates and population sizes of fish species in a Neotropical river and Lake Tanganyika, Africa, to evaluate the effects of simulated extinctions on nutrient recycling. In both of these species-rich ecosystems, recycling was dominated by relatively few species, but contributions of individual species differed between nitrogen and phosphorus. Alternative extinction scenarios produced widely divergent patterns. Loss of the species targeted by fishermen led to faster declines in nutrient recycling than extinctions in order of rarity, body size, or trophic position. However, when surviving species were allowed to increase after extinctions, these compensatory responses had strong moderating effects even after losing many species. Our results underscore the complexity of predicting the consequences of extinctions from species-rich animal communities. Nevertheless, the importance of exploited species in nutrient recycling suggests that overfishing could have particularly detrimental effects on ecosystem functioning.

Tetanus in the elderly—An important preventable disease in Australia

Notification trends from countries with well-established immunisation programs show increasing tetanus cases among the elderly, corresponding to seroepidemiologic data showing declining immunity with advanced age. We examined Australian trends in tetanus to review the likely value of routine funded immunisation at 65 years. Since 1993, 62% (36/58) of notifications, 44% (67/151) of hospitalisations and 83% (10/12) of deaths were in people aged over 65 years. Taking into account higher vaccine coverage at 65 years, versus the current recommended age in Australia of 50 years, we estimate that routine funded tetanus vaccine would prevent 9% more hospitalisations and 28% more deaths than the most favourable outcome from the current unfunded recommendation at 50 years. This is likely to be applicable to other industrialised countries.

Population-based seroprevalence of Neisseria meningitidis serogroup C capsular antibody before the introduction of conjugate vaccine, in Australia

Neisseria meningitidis serogroup C (NMC) conjugate vaccine was introduced, in Australia, in 2003. Our aims were to determine pre-immunisation IgG NMC seroprevalence and evaluate an enzyme-linked immunosorbent assay (ELISA), previously validated against the serum bactericidal assay (SBA). 2409 sera, collected in 2002, from subjects aged 2-34 years, were tested. The geometric mean concentration (GMC) of NMC anticapsular IgG was 0.38 U/mL in subjects under 19 years and it increased to 0.67 U/mL for those aged 30-34 years. Variation in GMC correlated with reported NMC disease incidence and was higher in males than females (0.52 U/mL versus 0.41 U/mL; p=0.005). The ELISA appears suitable for serosurveillance but the IgG level that correlates with protection needs further investigation. Serosurveys will be repeated to monitor the impact of vaccination.

Evaluation of two enzyme immunoassays for detection of immunoglobulin G antibodies to mumps virus

To determine suitability for national serosurveys, we compared two commercial enzyme-linked immunosorbent assays (ELISAs) for mumps antibody, Enzygnost Anti-Parotitis-Virus/IgG (which uses a whole-virus antigen) and Microimmune Mumps IgG Screen ELISA (which uses a recombinant nucleoprotein antigen), by testing 1,915 opportunistically collected sera submitted to diagnostic laboratories across Australia in 1997 to 1998. The proportion of positive results increased with age in both ELISAs but was significantly higher with the Microimmune than with the Enzygnost ELISA overall (88% versus 63%; P < 0.01) and in all age groups. However, the proportion of equivocal results was significantly higher with the Enzygnost than with the Microimmune ELISA (9% versus 4%; P < 0.01). Of the 572 sera with discrepant or equivocal results, 508 had sufficient sample remaining to perform the neutralization test (NT). A proportion with concordant results in both ELISAs were also tested by the NT. For sera with discrepant results, there was significantly better agreement between the NT and Microimmune than between the NT and Enzygnost (310/444 [70%] versus 135/348 [39%]; P < 0.01). Of 64 sera with equivocal Microimmune results, 45 (70%) were positive in the NT compared with 140 of 160 (88%) equivocal Enzygnost results (P < 0.01). Compared with the NT, the Microimmune ELISA is more sensitive (96% versus 80%) but apparently less specific (36% versus 85%) than the Enzygnost ELISA. However, this is likely to be due to the generally lower sensitivity of the NT, since the Microimmune results reflect expected seroprevalence, based on vaccine uptake in the age groups studied. We conclude that the Microimmune ELISA is a more appropriate assay than the Enzygnost ELISA for estimation of mumps seroprevalence.

Cellulitis in childhood invasive pneumococcal disease: a population-based study

AIM

There are few detailed data on the age-specific incidence and clinical pattern of pneumococcal cellulitis in children. We conducted a retrospective review of cellulitis as a subset of prospectively collected laboratory-identified invasive pneumococcal disease (IPD) and performed a systematic review of published literature.

METHODS

Prospective laboratory surveillance in urban regions of New South Wales, Australia, 1 June 1997-31 December 2001. Medical notes reviewed for each identified case and defined literature search strategy applied.

RESULTS

There were 1067 cases of IPD in children aged 0-17 years; 38 (3.3%) were cellulitis (32 periorbital, 6 buccal). Compared with other types of IPD, a greater proportion of cellulitis cases occur in children<2 years (30/38, 79% vs. 617/1029, 60.0%; P=0.004) in whom underlying illness was less common (0/30, 0% vs. 53/590, 9%; P=0.06). Initially, another diagnosis was made in 13 (34%) of cases; only five had a lumbar puncture, all normal. Of the 239 cases of pneumococcal cellulitis documented in the literature, 28 (11.7%) had the diagnosis made by means other than positive blood culture and 95% were facial or orbital with underlying illness (6%) and associated meningitis (1.9%) uncommon.

CONCLUSION

Cellulitis is an uncommon focus in IPD in children, and is almost always facial. Most cases occur under 2 years of age, are seldom associated with meningitis or other complications, and are frequently not recognised on admission.

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.

Rapid turnover of tissue nitrogen of primary consumers in tropical freshwaters

Stable isotopes are widely used as time-integrating tracers of trophic interactions, but turnover rates of isotopes in animal tissues remain poorly understood. Here, we report nitrogen (N) isotope turnover rates in tissues of four primary consumer species: Ancistrus triradiatus armored catfish (muscle, fins, and whole blood), Tarebia granifera snails (muscle), and Rana palmipes tadpoles (muscle) from a Venezuelan river, and Lavigeria grandis snails (muscle) from Lake Tanganyika, East Africa. Turnover was estimated from the dilution of a 15N label introduced into consumer tissues by feeding on 15N-enriched periphyton. Muscle turnover rates were rapid (0.5-3.8% per day), and were attributable to metabolic replacement of N as well as growth in catfish and snails. N turnover in catfish muscle decreased with size, and fin tissue turned over more rapidly than whole blood or muscle, though the difference was not significant. Our results indicate that stable isotope signatures of these tropical species could change markedly within weeks following a shift in diet. However, generalization across taxa or latitudes is complicated by the strong size-dependence of isotope turnover rates. The enrichment-dilution approach outlined here may facilitate measurement of isotopic turnover in a wide variety of consumers under field conditions.

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.

When science is not enough – a risk/benefit profile of thiomersal-containing vaccines

Without a preservative, such as thiomersal (known as thimerosal in the US), multi-dose liquid presentations of vaccine are vulnerable to bacteriological contamination that can result in death or serious illness of the recipient. Concerns about levels of mercury exposure from thiomersal-containing vaccines were first raised in the US during 1999 in the context of Hepatitis B vaccine for newborns. Since then, a large body of evidence from animal and epidemiological studies has accumulated on the safety of thiomersal. Ironically, these data have become largely irrelevant in wealthy countries, where mono-dose, thiomersal-free vaccines have been introduced as a precautionary measure in almost all childhood vaccines, in part related to residual public scepticism. In poor countries, multi-dose vials remain important for vaccine delivery. There is a real danger that this controversy may result in the loss to the world of thiomersal as a preservative, simply from popular pressure. In reality, it would be impossible to cease overnight using thiomersal and maintain the supply of vital vaccines. This paper reviews and summarises the data available from published studies on mercury toxicity, and thiomersal in vaccines in particular, that overwhelmingly indicate continued use of thiomersal is safe in those countries where it is most needed.

High levels of antibody in adults three years after vaccination with a reduced antigen content diphtheria-tetanus-acellular pertussis vaccine

There is increasing interest in prevention of pertussis in adults by vaccination, but little is known about the duration of the antibody response to pertussis, diphtheria or tetanus in reduced antigen content vaccines formulated for adult use. Follow-up of a clinical trial including 550 adults comparing responses to reduced antigen content diphtheria-tetanus-acellular pertussis (dTpa) vaccine, or a licensed Td vaccine, provided the opportunity to evaluate this. Blood samples were collected at 0, 1, 12, 24 and 36 months following vaccination; of the original cohort of 550, 387 subjects (dTpa group N=310, Td+pa group N=77) were tested at month 36. Following a decrease in antibody levels against all vaccine antigens between one and 24 months following vaccination, levels stabilized during the third year, remaining higher at 36 months than pre-vaccination for all vaccine antigens. In particular, more than 90% of subjects remained seropositive for pertussis toxin and pertactin antibodies at 36 months after vaccination, suggesting ongoing protection against pertussis. Adult-formulated dTpa vaccines could replace Td for routine booster vaccination of older individuals.

A boarding school outbreak of pertussis in adolescents: value of laboratory diagnostic methods

Culture for Bordetella pertussis (B. pertussis) is the traditional gold standard for laboratory diagnosis of pertussis but is insensitive, especially later in the course of illness and in vaccinated persons. Interpretation of serology is limited by the lack of an appropriate reference standard. An outbreak of pertussis in a crowded boarding-school dormitory allowed evaluation of laboratory correlates of infection. Questionnaires, serum samples and throat swabs were collected from members of the exposed group. Serum samples from unexposed controls of a similar age group were used for comparison. B. pertussis PCR was performed on throat swabs, and sera were tested for IgA antibodies against whole-cell (WC) B. pertussis antigen and IgG antibodies to pertussis toxin (PT). The Centers for Disease Control and Prevention definition for pertussis was used to define clinical cases. We evaluated the use of a previously published cut-off for PT IgG of 125 EIA units (EU)/ml. Completed questionnaires were obtained from 115 students, of whom 85 (74%) reported coughing symptoms, including 32 (28%) who met the clinical case definition for pertussis. B. pertussis was detected by PCR in 17 (15%) and WC IgA in 22 (19%) students; neither correlated with symptoms, but dormitory of residence strongly predicted PCR status. The mean PT IgG geometric mean concentration, in this situation of high pertussis exposure, correlated with severity of symptoms and was significantly higher in both symptomatic and asymptomatic children exposed during the outbreak (P < 0.001) than in control children. A cut-off for PT IgG of 125 EU/ml was too high in an outbreak situation to be sensitive enough to identify pertussis cases. A case of pertussis in a crowded boarding-school dormitory resulted rapidly in an outbreak. Serology and PCR were useful in identifying the outbreak and commencing disease control measures. The use of serology has mostly been evaluated in community serosurveys, where it is not possible to determine if immunity reflects vaccination, asymptomatic disease or symptomatic disease. This outbreak gave us the opportunity to evaluate the value of serology and PCR in the presence of confirmed exposure to pertussis.

A population based study of the impact of corticosteroid therapy and delayed diagnosis on the outcome of childhood pneumococcal meningitis

BACKGROUND

Despite an extensive literature, the impact of both adjunctive steroid therapy and delayed diagnosis on the outcome of childhood pneumococcal meningitis is controversial.

AIM

To determine the independent contribution of corticosteroid therapy and delayed diagnosis on the outcome of childhood pneumococcal meningitis in a representative population with good access to medical services.

METHODS

Data were obtained from laboratories and hospital records to assemble a population register in Sydney, Australia, 1994-99. Follow up questionnaires were completed by attending physicians.

RESULTS

A total of 122 cases of pneumococcal meningitis aged 0-14 years were identified. Almost 50% of 120 children with available records either died (n = 15) or had permanent neurological impairment (n = 39). Early use (before or with parenteral antibiotics) of corticosteroids protected against death or severe morbidity (adjusted OR 0.21, 95% CI 0.05 to 0.77). Delayed diagnosis was associated with increased morbidity in survivors (OR 3.4, 95% CI 1.03 to 11.4) but not with increased mortality.

CONCLUSION

In a population with good access to health care and after adjusting for other known prognostic variables, early recognition of pneumococcal meningitis and treatment with adjunctive dexamethasone significantly improves outcomes. These data add to those from randomised controlled trials. Implementation requires development of protocols and guidelines for use in emergency departments.

Immunisation: reducing health inequality for Indigenous Australians

Vaccination programs can act as a paradigm for effective health programs in Indigenous people.

Childhood asthma diagnosis and use of asthma medication

AIM

To determine the burden of asthma in children.

METHODS

A cross sectional, randomised, computer assisted telephone survey of a community based sample of 2020 children aged 5-14 years in western Sydney (New South Wales) over a 20 day period from June 2000 to July 2000.

RESULTS

Main outcome measures were carer reported history of asthma diagnosis, hospital presentation/admission for asthma, recent use of anti-asthma medications, and recent respiratory symptoms. Diagnosed asthma was reported in 31% (of whom 42% were diagnosed aged 2 years or under) and asthma medications used in the previous year by 21% of children. Factors significantly associated with a reported asthma diagnosis included: male gender (OR: 1.51), birth in Australia (OR: 1.64), living in an English speaking household (OR: 1.47), Aboriginality (OR: 2.32), possession of a health care card (OR: 1.28), previous pneumonia (OR: 2.4) or pertussis (OR: 2.0), and a recent episode of croup (OR: 1.9). Exposure to tobacco smoke and immunisation status were not significant.

DISCUSSION

We confirm a high prevalence of asthma and medication use for asthma. The high proportion of children diagnosed asthmatic at 2 years or under (when asthma cannot be diagnosed reliably) suggests overdiagnosis of asthma may contribute to the apparent high prevalence.

Influenza and pneumococcal vaccine coverage among a random sample of hospitalised persons aged 65 years or more, Victoria

This study was undertaken to assess the uptake of influenza and pneumococcal vaccination based on provider records of the hospitalised elderly, a group at high risk of influenza and pneumococcal disease. The study used a random sample of 3,204 admissions at two Victorian teaching hospitals for patients, aged 65 years or more who were discharged between 1 April 2000 and 31 March 2002. Information on whether the patient had received an influenza vaccination within the year prior to admission or pneumococcal vaccination within the previous five years was ascertained from the patient's nominated medical practitioner/vaccine provider. Vaccination records were obtained from providers for 82 per cent (2,804/2,934) of eligible subjects. Influenza vaccine coverage was 70.9 per cent (95% CI 68.9-72.9), pneumococcal coverage was 52.6 per cent (95% CI 50.4-54.8) and 46.6 per cent (95% CI 44.4-48.8) had received both vaccines. Coverage for each vaccine increased seven per cent over the two study years. For pneumococcal vaccination, there was a marked increase in 1998 coinciding with the introduction of Victoria's publicly funded program. Influenza and pneumococcal vaccine coverage in eligible hospitalised adults was similar to, but did not exceed, estimates in the general elderly population. Pneumococcal vaccination coverage reflected the availability of vaccine through Victoria's publicly funded program. A nationally funded pneumococcal vaccination program for the elderly, as announced recently, should improve coverage. However, these data highlight the need for greater awareness of pneumococcal vaccine among practitioners and for systematic recording of vaccination status, as many of these subjects will soon become eligible for revaccination.

Annual report: surveillance of adverse events following immunisation in Australia, 2004

This report summarises Australian passive surveillance data on adverse events following immunisation (AEFI) for 2004 and describes reporting trends over the five years, 2000 to 2004. AEFIs are notified to the Adverse Drug Reactions Advisory Committee by state and territory health departments, hospitals, doctors and other health providers, vaccine manufactures, and the public. There were 975 AEFI records for vaccines received in 2004. This is an annual AEFI reporting rate of 4.8 per 100,000 population, the lowest since 2000, and a 33 per cent decrease compared with 2003 (1,460 records; 7.1 AEFI records per 100,000 population). Dose-based AEFI reporting rates in 2004 were 1.8 per 100,000 doses of influenza vaccine for adults aged > or = 18 years and 11.8 per 100,000 doses of scheduled vaccines for children aged < 7 years. The majority of records described non-serious events while nine per cent (n = 88) described AEFIs defined as 'serious'. There were no reports of death related to immunisation. The most frequently reported individual AEFI was injection site reaction in children following a fifth dose of an acellular pertussis-containing vaccine (67 reports per 100,000 doses). The marked reduction in the AEFI reporting rate in 2004 coincided with the removal of the fourth dose of acellular pertussis vaccine, due at 18 months of age, from the vaccination schedule in September 2003 and fewer people receiving meningococcal C vaccine through the national catch-up vaccination program for those aged 1-19 years in 2004, compared with 2003. The consistently low reporting rate of serious AEFIs demonstrates the high level of safety of vaccines in Australia.

Effectiveness of a publicly funded pneumococcal vaccination program against invasive pneumococcal disease among the elderly in Victoria, Australia

Within Australia, Victoria is the only jurisdiction where the 23-valent polysaccharide pneumococcal vaccine (23vPPV) has been publicly funded for the elderly (aged > or = 65 years). We compared age-specific rates of invasive pneumococcal disease (IPD) for periods before and after implementation of the program, and data from a comparable Australian population that does not have a funded program. Vaccine effectiveness (VE) was estimated using the screening and indirect cohort methods. Compared to the pre-program period, there was a 36% reduction in the reported rates of IPD among persons aged > or = 65 years. Adjusted for under-reporting in the referent rate, the decrease was equivalent to an annual reduction of 112 cases and an estimated 14 deaths among persons > or = 65 years. VE was 71% (95% CI 54-82) using the screening method and 79% (95% CI -14 to 96) by the indirect cohort method. Both point estimates were consistent with the VE expected among persons aged > or = 65 years, although the small number of isolates meant the indirect cohort method was inconclusive at the lower 95% confidence limit. Consideration should be given to publicly funding pneumococcal vaccine for this age group in other settings.

Effects of behavioral and morphological plasticity on risk of predation in a Neotropical tadpole

Predator-induced phenotypic plasticity is widespread among aquatic animals, however the relative contributions of behavioral and morphological shifts to reducing risk of predation remain uncertain. We tested the phenotypic plasticity of a Neotropical tadpole ( Rana palmipes) in response to chemical cues from predatory Belostoma water bugs, and how phenotype affects risk of predation. Behavior, morphology, and pigmentation all were plastic, resulting in a predator-induced phenotype with lower activity, deeper tail fin and muscle, and darker pigmentation. Tadpoles in the predator cue treatment also grew more rapidly, possibly as a result of the nutrient subsidy from feeding the caged predator. For comparison to phenotypes induced in the experiment, we quantified the phenotype of tadpoles from a natural pool. Wild-caught tadpoles did not match either experimentally induced phenotype; their morphology was more similar to that produced in the control treatment, but their low swimming activity was similar to that induced by predator cues. Exposure of tadpoles from both experimental treatments and the natural pool to a free-ranging predator confirmed that predator-induced phenotypic plasticity reduces risk of predation. Risk of predation was comparable among wild-caught and predator-induced tadpoles, indicating that behavioral shifts can substantially alleviate risk in tadpoles that lack the typical suite of predator-induced morphological traits. The morphology observed in wild-caught tadpoles is associated with rapid growth and high competition in other tadpole species, suggesting that tadpoles may profitably combine a morphology suited to competition for food with behaviors that minimize risk of predation.

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.

Pertussis vaccination strategies for neonates—an exploratory cost-effectiveness analysis

Hospitalisation and death from pertussis in highly immunised populations largely occurs before the first vaccination at 2 months. A Markov model was constructed to estimate the costs and health consequences of three strategies to reduce pertussis over the first 6 months of an infant's life. Earlier vaccination (at either birth or 1 month in addition to current practice) or vaccination of the parents soon after birth was compared with the current practice of vaccination at 2, 4 and 6 months. The model was populated using data on the incidence and costs from Australia. Disability-adjusted life-years (DALYs) were used as the primary outcome measure. The cost to the Australian public health system was chosen as the economic perspective, and Monte-Carlo simulations were used to accommodate uncertainties in the variables. Vaccination at birth was estimated to cost (S.D.) an additional A$33.21 (A$1.60) per infant and to reduce cases, deaths and DALYs by 45%. Vaccination at 1 month was estimated to cost an additional A$43.24 (A$8.98) per infant and to reduce morbidity by approximately 25%. Parental vaccination at birth was the most expensive alternative, costing an additional A$73.38 (A$4.98) per infant and reducing pertussis morbidity by 38%. The costs per DALY averted were A$330,175 (A$15,461) A$735,994 (A$147,679) and A$787,504 (A$48,075) for the birth, 1 month and parental vaccination strategies, respectively. Changing the estimated factor by which hospitalisations and deaths are under-reported, and the efficacy of early vaccination, had large effects on results. Parental vaccination at birth was most cost-effective where protection persisted for subsequent children. The birth vaccination strategy appears to offer the greatest potential benefit for one-child families, but the efficacy at birth (and 1 month) needs to be established.

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.

Temporal trends in circulating Bordetella pertussis strains in Australia

Australia experienced a resurgence of pertussis in the 1990s despite improved vaccine coverage. Although much of the increase was attributable to increased detection of cases in older persons with waning immunity by serology, vaccine changes or alterations in circulating Bordetella pertussis strains may also have contributed. We determined the frequency of variants of B. pertussis pertactin (prn), and pertussis toxin subunit 1 (ptxS1) genes, restriction fragment length polymorphism (RFLP) types and fimbrial serotypes prevalent in Australia prior to, and during the 1990s. Ampoules of the whole-cell vaccine in use prior to 1999 and 84 B. pertussis isolates stored between 1967 and 1998 by laboratories around Australia were analysed. One pertactin allele, Prn3, not detected before 1985, was found in 24 out of 57 (42%) isolates between 1989 and 1998 (P<0.0001). PtxS1A was found in all isolates. IS1002 type 29, found in 17 out of 31 (55%) isolates tested, was the predominant RFLP type. The only difference in fimbrial serotype distribution between the time-periods was an increase in serotype 3 (P=0.054). The whole-cell vaccine contained only the alleles prn1 and ptxS1A. Antigenic shift in B. pertussis may have contributed to the re-emergence of pertussis in Australia. Monitoring these trends will be important as acellular vaccines are introduced and changes are made to pertussis vaccine schedules.

Community-based estimates of incidence and risk factors for childhood pneumonia in Western Sydney

The aim was to estimate the community incidence and risk factors for all-cause pneumonia in children in Western Sydney, Australia. A cross-sectional randomized computer-assisted telephone interview was conducted in July 2000, in Western Sydney. Parents of 2020 children aged between 5 and 14 years were interviewed about their child's respiratory health since birth. No verification of reported diagnosis was available. Logistic regression analysis was used to determine risk factors for pneumonia. A lifetime diagnosis of pneumonia was reported in 137/2020 (68%) children, giving an estimated incidence in the study sample of 7.6/1000 person-years. Radiological confirmation was reported in 85% (117/137). Hospitalization was reported in 41% (56/137) and antibiotic therapy in 93% (127/137) of cases. Using logistic regression modelling, statistically significant associations with pneumonia were a reported history of either asthma, bronchitis or other lung problems and health problems affecting other systems. In most cases, the diagnosis of asthma preceded the diagnosis of pneumonia. The community incidence of all causes of pneumonia is not well enumerated, either in adults or in children. This study provides community-based incidence data. The incidence of hospitalization for pneumonia in this study is comparable to estimates from studies in comparable populations, suggesting that retrospective parental report for memorable events is likely to be valid. We found a relationship between pneumonia and childhood respiratory diseases such as asthma, which has implications for targeted vaccination strategies.

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.

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.

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.

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.