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FALSE POSITIVES HINDER TB TESTS
Tuberculin skin tests (TST) performed on people vaccinated with BCG may show a false positive result, causing difficulty when interpreting results. Investigators in Canada carried out a meta-analysis of prospective studies looking at TST results and BCG vaccination status. Vaccination was found to make a positive TST more likely but the effect of vaccination was less after 15 years. The authors suggest that if a positive skin reaction is greater than 15 mm in size then it is more likely to be a result of tuberculosis infection than BCG vaccination. They recommend that BCG history should be taken into account when interpreting a TST. (
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RISKY FACTORS SURFACE FOR DRUG RESISTANT TB
Immunocompromised status, advanced age, and failure to culture within 30 days, or to apply appropriate treatment, influence poor mortality from multidrug resistant tuberculosis (MDRTB). TB is a major cause of morbidity and mortality, and MDRTB (resistance to at least isoniazid and rifampicin) is a serious global problem, affecting 1%–4% of new TB patients. Researchers followed up 90 UK MDRTB cases over 18 months. They found that immunocompromised patients were nine times more likely to die than their immunocompetent counterparts, that risk doubled with every 10 years of age, and that correct triple drug treatment (after accurate in vitro susceptibility testing) increased survival time. National UK survival is lower than for specialised centres so MDRTB should be managed in specialised centres with access to fast, accurate diagnosis and expert treatment supervision. (
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SAFETY IN NUMBERS, OR NOT
The European Community Respiratory Health Survey reports that children who were exposed to many other children at home or in day care develop less hay fever and more asthma. Over 18 000 subjects from 16 countries participated in the survey, which found that hay fever was less common in participants with many siblings and also those without siblings, but who were exposed to children in day care. Asthma symptoms however, were more common. The optimal number of siblings associated with fewest asthma symptoms was two. The study also found that the effect of exposure to children on adult asthma and hay fever was not mediated through production of specific IgE, so microbial stimulation from other children may help prevent allergic symptoms in atopic people. (
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PSYCHOSOCIAL FACTORS IMPLICATED IN ASTHMA DEATHS
The National Asthma Task Force has found that psychosocial factors may be implicated in asthma deaths. Factors associated with an increased risk of death appear to be psychosis, alcohol/drug misuse, financial/employment problems, and learning difficulties. However, anxiety, sexual problems, or prescription of antidepressant drugs are associated with a reduced risk of asthma death. Overall, 85% of cases and 86% of controls had a psychosocial problem. These associations, aside from alcohol/drug misuse, appeared independent of each other. Ultimately, the associations between health behaviour, psychosocial factors, and asthma death are varied and complex. (
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HAART HAMPERS HIV
The introduction of HAART (highly active antiretroviral therapy) for HIV patients has been shown to be an effective means of reducing the progression of AIDS in terms of population effectiveness trials. The observational cohort study set in Madrid, Spain measured the HIV progression from seroconversion over a 15 year period from 1985. Of the 226 seroconverters identified, the median seroconversion interval was 11 months, with most (89%) being male, of which 76% were homo/bisexual. HIV progression was also seen to be faster in those subjects with primary education only. In this regard, the implementation of HAART has implications for the effective management of HIV progression in many cities. (
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KNOWLEDGE GAP IN VIRAL STIs
Young women are less knowledgeable about viral STIs than about chlamydia, and have low awareness of the possibility of asymptomatic infection. Chlamydia infection decreased four-fold during the 1980s while viral STIs increased, indicating condom use is not prevalent enough. Researchers interviewed women three times over a seven year period: aged 16, 18, and 23. All 79 women knew about chlamydia transmission, 96% knew contact tracing was important and 80% knew it could be asymptomatic. However, less than half knew that human papilloma virus (HPV) and herpes could be asymptomatic. Risky sexual behaviour was a predictor of higher knowledge, but only 24% of women with a new or occasional partner had used condoms. (
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PAY PER SCREEN IS UNFEASIBLE
Screening for chlamydia in women attending the British Pregnancy Advisory Service (BPAS) for termination of pregnancy is feasible if there is no charge. Of women attending BPAS clinics for termination of pregnancy, 77% agreed to provide a urine sample; falling to 35% when asked to pay a £20 fee. The study found a 7.5% prevalence rate of C trachomatis. In most cases, test results were available within the clinical period of the termination of pregnancy. The authors suggest a BPAS/public health laboratory service collaboration would make a nationwide screening programme possible. (
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CONSENT CUSTOM CRITICISED
Individual informed consent should not be sought for participation in health services research (HSR) in the same manner as for clinical research, as has recently been adopted by UK ethics committees. The authors of a recent paper label the practice as “misguided”, and recommend that alternative forms of community consent should be actively pursued as, they argue, inappropriate consent requirements such as these can exacerbate existing health inequalities. Criticising ethics committees for “avoiding the wider issue of social exclusion as a core concern of the NHS”, the authors suggest that HSR should be regarded as an operational requirement of the NHS, and not as an analogue of clinical research. (
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