C.R. MacIntyre

Risk Factors for Tuberculosis

The risk of progression from exposure to the tuberculosis bacilli to the development of active disease is a two-stage process governed by both exogenous and endogenous risk factors. Exogenous factors play a key role in accentuating the progression from exposure to infection among which the bacillary load in the sputum and the proximity of an individual to an infectious TB case are key factors. Similarly endogenous factors lead in progression from infection to active TB disease. Along with well-established risk factors (such as human immunodeficiency virus (HIV), malnutrition, and young age), emerging variables such as diabetes, indoor air pollution, alcohol, use of immunosuppressive drugs, and tobacco smoke play a significant role at both the individual and population level. Socioeconomic and behavioral factors are also shown to increase the susceptibility to infection. Specific groups such as health care workers and indigenous population are also at an increased risk of TB infection and disease. This paper summarizes these factors along with health system issues such as the effects of delay in diagnosis of TB in the transmission of the bacilli.

Immunological responses to pneumococcal vaccine in frail older people.

UNLABELLED Advanced age has been associated with a wide range of defects in both the innate and adaptive immune systems including diminished specific antibody responses that increase the risk of invasive pneumococcal disease (IPD) and limit the effectiveness of vaccines. However, the elderly are a heterogeneous group and measures of overall frailty may be a better indicator of disease susceptibility (or vaccine response) than chronological age alone. AIM To evaluate the immunogenicity of the 7-valent conjugated pneumococcal vaccine (PCV7) versus 23-valent polysaccharide vaccine (23vPPV) and compare the immune response to four serotypes (4, 6B, 18C and 19F), with respect to age or frailty in an elderly population of previously unvaccinated hospitalized patients. METHOD 241 patients aged 60 years and over, recruited between 16 May 2005 and 20 February 2006, were randomised to 23PPV or PCV7 vaccine. We measured Frailty Index (FI), Barthel index and the MiniMental State. Serotype-specific IgG was measured by ELISA at base line and 6 months after vaccination. Antibody responses were defined by the ratio of post-vaccination to pre-vaccination IgG antibody concentration (poor < 2-fold increase, acceptable > or = 2.0 to 3.99-fold and strong > or = 4.0-fold increase). RESULTS Pre-immunization IgG was generally low and did not differ significantly by age or frailty. Post-immunization, IgG increased to all four serotypes; acceptable or strong response ranged between 29% for (6B) and 57% for (18C). There was no significant difference between the two vaccine types (23PPV versus PCV7). At 6 months post-vaccination, the highest geometric mean IgG concentrations (GMCs) were seen for serotype 19F and the lowest for serotype 4. Although there was some variation by serotype, responses after vaccination were lowest in the most frail or aged subjects. CONCLUSIONS Pneumococcal vaccines are perceived to offer low protection in the frail elderly, but our study showed that the proportion of this vulnerable population with acceptable responses is encouraging. Frailty, as measured by the Frailty Index, appears to be a better predictor of immune response to pneumococcal vaccines than age alone.

Health Care Provider Adoption of eHealth: Systematic Literature Review

Background eHealth is an application of information and communication technologies across the whole range of functions that affect health. The benefits of eHealth (eg, improvement of health care operational efficiency and quality of patient care) have previously been documented in the literature. Health care providers (eg, medical doctors) are the key driving force in pushing eHealth initiatives. Without their acceptance and actual use, those eHealth benefits would be unlikely to be reaped. Objective To identify and synthesize influential factors to health care providers’ acceptance of various eHealth systems. Methods This systematic literature review was conducted in four steps. The first two steps facilitated the location and identification of relevant articles. The third step extracted key information from those articles including the studies’ characteristics and results. In the last step, identified factors were analyzed and grouped in accordance with the Unified Theory of Acceptance and Use of Technology (UTAUT). Results This study included 93 papers that have studied health care providers’ acceptance of eHealth. From these papers, 40 factors were identified and grouped into 7 clusters: (1) health care provider characteristics, (2) medical practice characteristics, (3) voluntariness of use, (4) performance expectancy, (5) effort expectancy, (6) social influence, and (7) facilitating or inhibiting conditions. Conclusions The grouping results demonstrated that the UTAUT model is useful for organizing the literature but has its limitations. Due to the complex contextual dynamics of health care settings, our work suggested that there would be potential to extend theories on information technology adoption, which is of great benefit to readers interested in learning more on the topic. Practically, these findings may help health care decision makers proactively introduce interventions to encourage acceptance of eHealth and may also assist health policy makers refine relevant policies to promote the eHealth innovation.

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.

A cluster randomized clinical trial comparing fit‐tested and non‐fit‐tested N95 respirators to medical masks to prevent respiratory virus infection in health care workers

Please cite this paper as: MacIntyre et al. (2011) A cluster randomized clinical trial comparing fit‐tested and non‐fit‐tested N95 respirators to medical masks to prevent respiratory virus infection in health care workers. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2010.00198.x.

Difficulties in recruiting older people in clinical trials: An examination of barriers and solutions

Limited information exists regarding optimal methods for the recruitment and retention of older people in clinical trials. The aim of this review is to identify common barriers to the recruitment of older people in clinical trials and to propose solutions to overcome these barriers. A review of literature was performed to identify common difficulties in recruiting older people. This in combination with our experience during recruitment for a randomized control trial, have highlighted numerous barriers. Population-specific recruitment strategies, simple informed-consent processes, and effective communication between the researcher and subject are effective strategies to overcome these barriers.

Epidemiology of paediatric invasive fungal infections and a case-control study of risk factors in acute leukaemia or post stem cell transplant.

Patients aged 0–18 years with confirmed or possible invasive fungal infection were identified by medical record and database searches. Cases with an underlying diagnosis of acute leukaemia or following stem cell transplantation were included in a case control study. Controls included all other children with acute leukaemia or stem cell transplant in the corresponding time period. Variables collected included demographics, underlying disease risk and status, organ impairment, admission to intensive care unit, fungal infection details and certain transplant variables. Risk factors for development of invasive fungal infection were examined using logistic regression. There were 106 cases of invasive fungal infection during the study. The incidence of invasive fungal infection was 21% in acute lymphoblastic leukaemia, 15% in acute myeloid leukaemia and 25% following stem cell transplantation. Sixty per cent were neutropenic at diagnosis and 39% had concomitant bacteremia. High risk acute lymphoblastic leukaemia, relapsed disease, intensive care admission and graft‐versus‐host disease were significantly associated with development of invasive fungal infection on multivariate analysis. These associations provide new information on paediatric invasive fungal infections and warrant further study; caution should be encouraged when extrapolating from adult studies.

Differences in attitudes, beliefs and knowledge of hospital health care workers and community doctors to vaccination of older people

UNLABELLED Pneumococcal disease and influenza are major causes of morbidity and mortality particularly among the elderly. Influenza and pneumococcal vaccination are recommended for people aged 65 years and older or persons with chronic illness. However, despite the burden of disease related to pneumococcus and influenza and the availability safe, efficacious and cost-effective vaccines, health care providers continue to have doubts about these vaccines. Little is known about barriers for pneumococcal vaccination in the health care providers particularly in the primary health care setting. Since 2005 a publicly funded program offering free pneumococcal vaccine for elderly people over 65 years has been implemented in Australia. AIM To investigate knowledge, attitudes and practices around vaccination of elderly patients among hospital health care workers and community general practitioners and to explore the difference between hospital doctors and GP. METHODS A self-reported questionnaire survey distrubuted March and June 2007 to General physicians (GPs) whose practices are located in Western Sydney and health care staff consisting of Hospital Doctors (HD), hospital nurses (HN) and allied health care workers at a tertiary referral hospital in Western Sydney. Descriptive analyses were conducted; bivariate analyses were performed to investigate associations between variables. RESULTS Completed surveys were obtained for 56.3% (335/595) GPs and 42.1% (346/822) for HHCWs. The HHCWs comprised 37.5% (130/346) HD, 57.8% (200/346) HN and 4.6% (16/346) allied health care workers. GPs are more likely to support elderly vaccination than hospital doctors (98.8% compared to 93%, P=0.0007). GPs reported that the reason for not vaccinating patients in 88% (295/335) of the cases was due to patient refusal. GPs and HHCW both agreed that pneumococcal disease is a serious illness and that vaccination is an important preventive measure for the elderly. However, the majority 68.2% (88/129) of hospital doctors report that vaccinations are difficult to address due to multiple competing priorities compared to only 34.6% (116/335) of GPs, P<0.0001. Hospital doctors are more likely than GPS (24% vs. 17%) to report that patients often complain of adverse effects from pneumococcal vaccine. Hospital doctors 20% (104/130) are significantly less likely than GPs<1% (3/335) to have access to guidelines and other information regarding vaccination in the elderly. CONCLUSIONS GPs and hospital health care workers in our study were aware of, agreed with, immunization recommendation for the pneumococcal vaccine. Physician barriers to vaccination were patients refusals and competing priorities, particularly for hospital health care workers, who were less likely to see vaccination as a priority. Hospitalisation is an opportunity for vaccination, but utilisation of this opportunity is reduced by lack of access to information about immunization for hospital health care workers and competing priorities. These could be areas to target for improved uptake of the elderly immunization.

Seasonal influenza vaccination in Australian hospital health care workers: a review.

Objective: To review the uptake of seasonal influenza vaccination among hospital health care workers (HCWs) in Australia to date.

The seroepidemiology and transmission dynamics of varicella in Australia.

To enhance our understanding of the epidemiology and transmission dynamics of varicella in the pre-vaccine era we performed a serosurvey using opportunistically collected sera submitted to diagnostic laboratories across Australia during 1997-1999. A representative sample by state and sex of 2027 sera from persons aged 1-49 years was tested using an enzyme immunoassay method. The average age of infection and age-specific forces of infection (the probability that a susceptible individual acquires infection) were calculated using published methodologies. Seropositivity increased with age, with 83% of sera positive by ages 10-14 years. The highest force of infection was in the 5-9 years age group (0.195 per susceptible year) followed by the 0-4 years age group (0.139 per susceptible year) and the average age of infection was 8.15 years. These results provide valuable baseline information to measure the impact of vaccination and indicate that vaccination should be aimed at children less than 5 years of age, although further modelling using the serosurvey data is warranted.