The relative importance of rotavirus and other pathogens in the etiology of gastroenteritis in Trinidadian children.

Over a 2-year period, 300 infants less than 3 years old with gastroenteritis admitted to hospitals in Trinidad were investigated for the presence of certain microorganisms in the feces, along with an equal number of age- and sex-matched controls. Rotavirus was detected in 23% of cases and 1% of controls; Salmonella in 7% of cases and in 1% of controls; Shigella in 4% of cases and in no controls and two serotypes of enteropathogenic E. coli in 7% of cases and in 2% of controls. Campylobacter fetus subspecies jejuni was cultured from 7 out of 60 cases and from 1 of 60 controls. Enterotoxigenic E. coli, most strains of enteropathogenic E. coli, cytopathic enteroviruses and adenoviruses and fecal parasites were not significantly associated with diarrhea. Rotaviruses were detected throughout the year but were more prevalent in the dry than in the rainy season. They were found less often in children younger than 6 months than in those aged 6 to 35 months and were present in 6 of the 20 children who died.

A mathematical model to measure the impact of the Measles Control Campaign on the potential for measles transmission in Australia.

BACKGROUND: The aims of this study were to determine the impact of the Australian Measles Control Campaign (MCC) on the transmission dynamics of measles by calculating the reproductive number (R) before and after the MCC, and to predict measles control in Australia in the future. METHODS: A national serosurvey was conducted before and after the MCC. Sera were tested for anti-measles IgG using enzyme immunoassay (EIA). A mathematical model, using serosurvey results and vaccine coverage estimates, was used to calculate the change in R after the MCC. RESULTS: The values of R calculated before and after the MCC were 0.90 and 0.57. At vaccine coverage levels indicated by the Australian Childhood Immunisation Register (ACIR), the value of R will exceed 1 (the epidemic threshold) in 2007-2008 nationally, and sooner in some regions of Australia. Coverage of at least 84% with two doses of MMR is required to sustain measles control. CONCLUSIONS: The Australian MCC had a significant impact on the transmission dynamics of measles. However, current vaccine coverage levels may result in indigenous measles transmission by 2007. Sustained efforts are required to improve coverage with two doses of MMR and to ensure elimination of indigenous measles transmission.

Immunisation coverage reporting through the Australian Childhood Immunisation Register--an evaluation of the third-dose assumption.

OBJECTIVE: The Australian Childhood Immunisation Register (ACIR) currently classifies those children who have the third dose recorded as fully immunised at 12 months of age, even if records of earlier doses are missing. This analysis assesses the impact this "third-dose assumption" has on immunisation coverage estimates for children aged 12 months. METHODS: ACIR records from three equally spaced cohorts of children at 12 months of age, which relied on the third-dose assumption, were examined for variation in doses and vaccine types recorded by jurisdiction and Medicare registration status. RESULTS: Although the percentage reduction in coverage without application of the third-dose assumption decreased through the three cohorts examined, the proportion classified as fully immunised still decreased by 11-12% (to < 75%) if the third-dose assumption was not used in the most recent cohort. "Fully immunised" status among children with delayed Medicare registration or in jurisdictions with a high proportion of paper reporting to the ACIR was disproportionately reduced without use of the assumption. CONCLUSIONS AND IMPLICATIONS: While independent sources of data continue to show that the ACIR incorrectly classifies some children as not fully immunised even with the third-dose assumption, its use seems appropriate for reporting population trends in immunisation coverage. Earlier Medicare registration and increased electronic reporting to the ACIR, together with incentives for parents and providers to ensure complete ACIR records, should eventually eliminate the need for the third-dose assumption.

Factors associated with low uptake of measles and pertussis vaccines--an ecologic study based on the Australian Childhood Immunisation Register.

OBJECTIVE: To evaluate the relationships between socio-economic and demographic variables and low immunisation coverage at the national level. METHODS: The Australian Childhood Immunisation Register (ACIR) contains data at the postcode level on the immunisation status of all children registered with Medicare under the age of seven years. The Australian Bureau of Statistics (ABS) produces a number of indicators of socio-economic status at the postcode level from Census data. These and other ABS demographic data were used to examine the relationship between immunisation coverage and various socio-demographic indicators. RESULTS: Factors associated with lower immunisation uptake differed in rural and metropolitan areas. High levels of education and occupation and a high proportion of Aboriginal residents were significantly associated with lower coverage only in metropolitan postcodes. High unemployment was associated with lower immunisation coverage only in rural postcodes. A high proportion of late starters to immunisation was the strongest single predictor of coverage and was important in rural and metropolitan postcodes. A high proportion of overseas-born persons and of GP-delivered immunisations was also associated with lower coverage in all areas. CONCLUSIONS: These data suggest that in metropolitan areas, reasons for low uptake in more advantaged areas require further evaluation. In non-metropolitan areas, low coverage was associated with areas of disadvantage, for which access to services may be more important. IMPLICATIONS: Children who are late in starting the schedule should be targeted.

Measuring immunisation coverage in Australia. A review of the Australian Childhood Immunisation Register.

BACKGROUND: Before the establishment of the Australian Childhood Immunisation Register (ACIR), measurement of childhood immunisation coverage in Australia involved a variety of methods at varying intervals by general practice (GP) divisions, state health departments and the Australian Bureau of Statistics. Such surveys may underestimate (child health records) or overestimate (parental recall) true immunisation coverage. OBJECTIVE: The establishment of the ACIR in 1996 (a world first), was a huge undertaking involving 15,000 immunisation providers (60% GPs) notifying over 3 million immunisations annually. This review summarises the operation of the ACIR, how it calculates coverage, the accuracy of estimates from the ACIR and how Australia's immunisation coverage compares with that of other similar countries. Currently, the accuracy of the records on the register is questioned, especially in urban areas, but available data suggest that failure to report to the ACIR is the main source of data discrepancies. DISCUSSION: The ACIR has the potential to measure immunisation coverage at any practice or local level with accuracy and timeliness. With full provider participation, the ACIR is capable of identifying areas of low immunisation coverage for targeted interventions and will play a key role in the current measles campaign, the General Practice Immunisation Incentives scheme and in payments to parents. Achieving the highest possible completeness and timeliness of the ACIR is in the interests of providers, consumers and health planners.

Poliovirus surveillance: building the global Polio Laboratory Network.

A network of virologic laboratories has been established by the World Health Organization to conduct surveillance for wild poliovirus and to provide evidence for the certification of poliomyelitis eradication. The network consists of >60 national laboratories isolating and identifying polioviruses within countries; 16 regional reference laboratories, providing intratypic differentiation of wild and vaccine strains and assisting with quality assurance and training; and 6 global specialized laboratories, conducting research, preparing reference reagents, and providing genomic sequencing of wild polioviruses, advanced training, and expert virologic advice. Laboratories collaborate with national eradication programs in the detection, reporting, clinical investigation, and virologic testing of stool specimens obtained in connection with cases of acute flaccid paralysis and, where indicated, from healthy children and the environment. A quality assurance system, leading to World Health Organization accreditation, involves training in standardized techniques, use of centrally prepared typing antisera, annual proficiency testing and follow-up action, and monitoring of standard performance indicators.

A re-evaluation of immunisation coverage estimates from the Australian Childhood Immunisation Register.

Immunisation coverage reporting using data from the Australian Childhood Immunisation Register is likely to underestimate immunisation uptake. Since 1997, several initiatives have been introduced to improve both immunisation uptake and notification of immunisation encounters. These initiatives seemed likely to have changed previous coverage estimates. Re-calculation of immunisation coverage estimates for the previously reported cohorts was undertaken. This used current Australian Childhood Immunisation Register data--especially the immunisation history form and the impact of catch-up immunisations--to evaluate delayed reporting. Previous coverage estimates published in Communicable Diseases Intelligence were shown to be at least 2% to 4% below estimates based on data now held by the Australian Childhood Immunisation Register, with greater differences observed in particular jurisdictions.

An empirical study of preferred settings for lumbar support on adjustable office chairs.

The preferred settings for lumbar support height and depth of 43 male and 80 female office workers were investigated. All subjects were equipped with identical modern office chairs with foam-padded backrests adjustable in both height and depth. Measurements of lumbar support settings were recorded in the workplace, outside of working hours, on four different occasions, over a 5 week period. Preferred lumbar support height and depth settings extended to both extremes of the adjustment range. The mean preferred height setting was 190 mm above the compressed seat surface. The mean depth setting (horizontal distance from front of seat to lumbar support point) was 387 mm. A regression model examining the effects of standing height, Body Mass Index (BMI) and gender on mean preferred lumbar support height showed a significant relationship between preferred height and BMI. Higher lumbar supports were chosen by subjects with greater BMIs. Gender and standing height were not associated with preferred lumbar support height settings. Preferred lumbar support depth was not significantly associated with standing height, gender or BMI. Older subjects were more likely to readjust their lumbar support from a disrupted position than younger subjects, indicating that older users are more sensitive to the position of their lumbar support. Subjects who reported recent back pain or discomfort that they believed to be associated with their chair or office work were found to set their lumbar support significantly closer to the front of the seat, probably to ensure greater support for their back. Based on the evidence that a high proportion of users do make adjustments to the height and depth of their lumbar support, and the finding that different groups of users, with different physical characteristics, adjust the position of their lumbar support in distinct and predictable ways, the researchers conclude that office chairs with traditional padded fixed-height lumbar supports are unlikely to provide a comfortable or appropriate seat for the wide range of potential users.

Polio eradication in the World Health Organization South-East Asia Region by the year 2000: midway assessment of progress and future challenges.

In the South-East Asia Region (SEAR) of WHO, paralytic poliomyelitis has decreased from 25,711 cases in 1988 to 3304 cases in 1995, representing an 87% reduction. By 1995, in 6 of 10 member countries--India, Bangladesh, Myanmar, Nepal, Indonesia, and Democratic People's Republic of Korea--polio remained endemic. Two countries, Sri Lanka and Thailand, appear close to polio eradication, and 2, Bhutan and Maldives, reported no cases during 1989-1995. Although reported rates of acute flaccid paralysis and the percentage of cases virologically investigated are low in some countries, no isolates of wild poliovirus type 2 have been reported outside India since 1993. By the end of 1996, all 8 countries in which polio is endemic will have conducted national immunization days for polio eradication. The major challenge for polio eradication in SEAR will be strengthening surveillance, because national immunization days alone cannot eradicate polio.

Poliomyelitis surveillance: the compass for eradication.

Effective disease surveillance is a key strategy of the global polio eradication initiative. In an effort to strengthen the quality of polio surveillance as a prerequisite to achieving and certifying eradication, surveillance assessments were conducted in 28 countries in the World Health Organization African, Eastern Mediterranean, and European Regions from 1992 to 1995 using a standard protocol and evaluation guidelines. Six general recommendations were made: Use surveillance data for public health decision-making and action, improve timeliness of information exchange and dissemination, standardize the data collected, ensure adequate surveillance infrastructure, improve local data analysis, and enhance teamwork among surveillance partners. The experience gained will position the Expanded Programme on Immunization to address the challenges of disease prevention in the 21st century.

Yellow fever: a decade of reemergence.

Since the 1980s, yellow fever has reemerged across Africa and in South America. The total of 18 735 yellow fever cases and 4522 deaths reported from 1987 to 1991 represents the greatest amount of yellow fever activity reported to the World Health Organization (WHO) for any 5-year period since 1948. There is an excellent vaccine against yellow fever. At present, a high proportion of travelers to at-risk areas are reported to be immunized, reflecting widespread knowledge about the International Health Regulations. In South America, yellow fever remains an occupational hazard for forest workers, who should be immunized. However, Aedes aegypti mosquitoes are now present in urban areas in the Americas (including southern parts of the United States), and there is concern that yellow fever could erupt in explosive outbreaks. In Africa, a large proportion of cases have occurred in children. The WHO, the United Nations Children's Fund (UNICEF), and the World Bank have recommended that 33 African countries at risk for yellow fever add the vaccine to the routine Expanded Programme on Immunization; studies show that this would be highly cost-effective. To date, financing yellow fever vaccine has been a major problem for these countries, which are among the poorest in the world. For this reason, WHO has launched an appeal to raise $70 million for yellow fever control in Africa.

Quantitative relation between emphysema and lung mineral content in coalworkers.

The relation between quantified emphysema and measured lung content of coal and silica was investigated in the lungs of 264 deceased underground coalworkers who had been exposed to mixed coal and silica dust. Lung specimens obtained at postmortem and inflated and fixed under standard conditions were used to quantify the extent of emphysema and then to measure the amount of coal and silica present in the lungs at the time of death. These data were combined with clinical and other pathological information from the subjects. Multiple regression analysis showed that the extent of emphysema (E score) had a strong positive quantitative relation with coal content of the lungs (p < 0.0003), age (p < 0.0001), and smoking (p < 0.0001). There was a significant negative interaction of uncertain biological importance between coal content of the lungs and smoking (p < 0.004; E score = -1.79 + 0.62 coal + 0.06 age + 0.21 smoking -0.17 coal x smoking; adjusted R2 = 0.25). In lifelong non-smokers emphysema was particularly strongly related to coal content and age (coal: p < 0.001; age: p < 0.002; E score = -1.56 + 0.78 coal + 0.06 age; adjusted R2 = 0.66). The relation was basically unchanged by adding a lung silica content term. Emphysema score was highly negatively correlated with forced expiratory volume in one second (FEV1; % predicted, obtained within five years of death) (r = -0.44, p < 0.0001). Degree of lung fibrosis was highly positively associated with lung silica content (chi 2(1) = 12.9, p < 0.0003). These results provide strong evidence that emphysema in coalworkers is actually related to lung coal content. The role silica in development of emphysema, however remains unclear.

Paralytic poliomyelitis: seasoned strategies, disappearing disease.

With more than 2 years having elapsed since the last case of paralytic poliomyelitis occurred in the Western Hemisphere, significant progress has been made towards the global eradication of wild polioviruses. Poliomyelitis is disappearing from Europe, North Africa, Southern Africa, the Middle East, China, and the Pacific. Reported poliomyelitis cases declined to 15,587 cases in 1992. Current eradication strategies recommended by the World Health Organization include national mass campaigns administering oral poliovaccine to all children under 5 years of age, enhanced surveillance to detect cases of acute flaccid paralysis, creating a network of laboratories for viral diagnosis, and targeted immunisation to areas and populations where poliovirus transmission is likely to persist. The major obstacles to eradication include inadequate political support for eradication and insufficient funding, especially for the purchase of vaccine. With additional support for the international eradication effort, epidemics of poliomyelitis will cease in developing countries, and industrialised countries will be able to save the large sums spent each year on poliovaccine and rehabilitation.

Unintentional fatal injuries arising from unpaid work at home.

OBJECTIVE: Unpaid work in and around the home is a common and potentially high risk activity, yet there is limited information about the circumstances surrounding resulting injuries. This study aimed to describe circumstances surrounding fatal injuries resulting from home duties activities, in order to identify and prioritise areas for prevention. DESIGN AND SETTING: Coroners' reports on all unintentional deaths in Australia from 1989-92 inclusive were inspected to identify deaths of interest. Rates were calculated using population data and incorporating measures of time engaged in particular home duties activities. RESULTS: There were 296 home duties deaths over the four year period. Most (83%) deaths were of males, and males had 10 times the risk of fatal injury compared with females. The most common activities resulting in fatal injuries were home repairs, gardening, and car care. The highest risk activities (deaths per million persons per year per hour of activity) were home repairs (49), car care (20), home improvements (18), and gardening (16). Being hit by inadequately braced vehicles during car maintenance, falls from inadequately braced ladders, contact with fire and flames while cooking, and contact with electricity during maintenance were the most common injury scenarios. CONCLUSIONS: Fatal injury of persons engaged in unpaid domestic work activities is a significant cause of death. Use of activity specific denominator data allows appropriate assessment of the degree of risk associated with each activity. The recurrence of similar circumstances surrounding many independent fatal incidents indicates areas where preventative interventions might be usefully targeted.

The WHO-EPI initiative for the global eradication of poliomyelitis.

Since the development of attenuated oral polio vaccine, Dr Albert Sabin consistently maintained that the global eradication of wild poliovirus was possible, but that to achieve polio eradication in developing countries would require the mass administration of the oral vaccine. Experience in Cuba and Czechoslovakia proved the effectiveness of this technique, but it was only with its deployment in Brazil in 1980 that its role in eradicating the virus from a broad geographical area started to be realized. With the declaration in 1985 of a target of regional polio eradication, extension of this policy, allied with the development of effective surveillance of acute flaccid paralysis in children, with laboratory confirmation of diagnosis rapidly led to apparent interruption of wild poliovirus transmission throughout the Americas. The World Health Assembly in 1988 committed WHO to the global eradication of poliomyelitis. Based on experience in the Americas and building on the solid foundation established by the Expanded Programme on Immunization, WHO has defined the strategies through which the global target could be achieved. Progress is encouraging and where the advocated strategies have been fully implemented, the incidence of poliomyelitis has declined dramatically. Significant geographical areas in Western Europe, the Maghreb, the Arabian peninsula, the Pacific basin and Southern Africa, each incorporating several countries, are now thought to be free of the disease caused by wild poliovirus. The target of a world free of polio by the year 2000 can be achieved.

Comparative study of five methods for intratypic differentiation of polioviruses.

A coded panel of 90 poliovirus isolates, 30 of each of the three known serotypes, was used to evaluate five methods for the intratypic differentiation of polioviruses: (i) an enzyme-linked immunosorbent assay with polyclonal cross-absorbed antisera (PAb-E), (ii) a neutralization assay with type-specific monoclonal antibodies (MAb-N), (iii) a restriction fragment length polymorphism (RFLP) assay, (iv) a Sabin vaccine strain-specific PCR assay, and (v) a Sabin vaccine strain-specific cRNA probe hybridization (ProHyb) assay. Sequence analysis was used for the definitive characterization of the strains. The panel was distributed to five laboratories; each laboratory analyzed the strains by at least two methods. Each method was used by three or four laboratories. The total performance scores (percentage correct results per number of tests) of the five methods were 96.7% for PAb-E, 93.9% for MAb-N, 91.9% for RFLP assay, 93.3% for Sabin vaccine strain-specific PCR, and 97.4% for Sabin vaccine strain-specific ProHyb. Consistent results were obtained by each laboratory for 88 of 90 isolates (97.8%) examined by PAb-E, 81 of 90 isolates (90.0%) examined by MAb-N, 78 of 90 isolates (86.7%) examined by RFLP assay, 81 of 90 isolates (90.0%) examined by PCR, and 89 of 90 isolates (98.9%) examined by ProHyb assay. Six strains were classified differently by different methods. It is recommended that at least two methods be used for the intratypic differentiation of poliovirus isolates, and each method should be based on a different principle (i.e., antigenic properties and nucleotide sequence composition). If two assays yield discrepant results, further characterization, preferably by partial sequence determination, will be required for correct identification.

The Australian Measles Control Campaign, 1998.

The 1998 Australian Measles Control Campaign had as its aim improved immunization coverage among children aged 1-12 years and, in the longer term, prevention of measles epidemics. The campaign included mass school-based measles-mumps-rubella vaccination of children aged 5-12 years and a catch-up programme for preschool children. More than 1.33 million children aged 5-12 years were vaccinated at school: serological monitoring showed that 94% of such children were protected after the campaign, whereas only 84% had been protected previously. Among preschool children aged 1-3.5 years the corresponding levels of protection were 89% and 82%. During the six months following the campaign there was a marked reduction in the number of measles cases among children in targeted age groups.