PubMed Health⌕ Search

Biomedical subjects

V Demicheli

Publications and source records attributed to V Demicheli.

At least 37 records · Page 2Linked to original sources

Prevention and early treatment of influenza in healthy adults.

INTRODUCTION: We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a different influenza intervention in healthy adults: Vaccines; Ion Channel Inhibitor antivirals and Neuraminidase Inhibitor (NIs) antivirals. The objectives were to identify, retrieve and assess all studies evaluating the effects of these interventions in prophylaxis and early treatments of influenza and the frequency of adverse events. Additionally we present the results of the economic evaluation of effective alternatives in order to define the most cost-effective intervention. The economic evaluation is set in the context of the British Army. METHODS: Studies were identified using a standard Cochrane search strategy. Any randomised or quasi-randomised studies in healthy individuals aged 14-60 years were considered for inclusion in the systematic review. Those which met inclusion criteria were assessed for quality and their data meta-analysed. The economic model was constructed using Cost-effectiveness and Cost-utility study designs. RESULTS: Live aerosol vaccines reduced cases of clinical influenza A with virological confirmation (by serology and/or viral isolation) by 48% (95%CI: 24-64%), whilst recommended inactivated parenteral vaccines have an efficacy of 68% (95%CI: 49-79%). Vaccine effectiveness in reducing clinical influenza cases (i.e. without virological confirmation) was lower, with efficacies of 13 and 24% respectively. Use of the vaccine significantly reduced time off work, but only by 0.4 days (95%CI: 0. 1-0.8 days). Analysis of vaccines matching the circulating strain gave higher estimates of efficacy, whilst inclusion of all other vaccines reduced the efficacy. When compared to placebo for the prevention of influenza, oral amantadine was 61% (95%CI: 51-69%) efficacious (RR 0.39 - 95%CI: 0.31-0.49), and oral rimantadine was 64% (95%CI: 41-78%) efficacious (RR 0.36 -95%CI: 0.22-0.59). When compared to placebo for the treatment of influenza, oral amantadine significantly shortened duration of fever (by 1.00 days - 95%CI: 0. 73-1.29), and oral rimantadine significantly shortened duration of fever (by 1.27 days - 95%CI: 0.77-1.77). When compared to placebo, NIs were 74% (95%CIs: 50-87%) effective in preventing naturally occurring cases of clinically defined influenza. In a treatment role, NIs shortened the duration of symptoms by one day (Weighted Mean Difference - 1.0; 95%CIs: -1.3 to - 0.6) when a clinical case definition is used. The economic results show that in healthy adults, inactivated vaccines appear the best buy. CONCLUSIONS: If assessed from the point of view of effectiveness and efficiency, vaccines are undoubtedly the best preventive means for clinical influenza in healthy adults. However, when safety and quality of life considerations are included, parenteral vaccines have such low effectiveness and high incidence of trivial local adverse effects that the trade-off is unfavourable. This is so even when the incidence of influenza is high and adverse effect quality of life preferences are rated low. We reached similar conclusions for antivirals and NIs even at high influenza incidence levels. On current evidence we conclude in healthy adults aged 14-60 the most cost-effective option is not to take any action.

Adolescent↗

Vaccines for preventing hepatitis B in health-care workers.

BACKGROUND: Hepatitis B causes acute and chronic liver disease and may be prevented by vaccination. OBJECTIVES: To assess the effectiveness and safety of plasma-derived vaccines against acute and chronic hepatitis B in health-care workers in protecting them from hepatitis B infection and its consequences. SEARCH STRATEGY: MEDLINE and Excerpta Medica Database (EMBASE) search using standard Cochrane strategy, Cochrane Library, full text searching of the journal "Vaccine", bibliography of retrieved studies and correspondence with authors, researchers and manufacturers. SELECTION CRITERIA: All original prospective randomised comparisons of yeast-derived vaccines and plasma-derived vaccines against no intervention, placebo, or vaccines against other disease (control vaccines). Assessment of trial quality was made according to: 1. generation of allocation schedule 2. measure(s) taken to conceal treatment allocation 3. drop-out of allocated health-care worker participants from the analysis of trial results 4. measures taken to implement double blinding Trial reports were blinded by removal of authors and their affiliation, journal reference, introduction, results, and discussion. DATA COLLECTION AND ANALYSIS: To assess efficacy the incidence rates of acute hepatitis B were observed in the surveillance of the vaccinated and control groups of the trials included in the review. Safety was assessed from side-effect rates, classified as systemic (malaise, nausea, fever, arthralgias, rash, headache) or local (induration and soreness at the site of the inoculation). MAIN RESULTS: Four trials fulfilling the criteria were identified and the data synthesised. All trials compared plasma-derived vaccines versus placebo. Differences in the settings (and level of incidence) between three of the trial settings and Dienstag's led us to stratify our comparison grouping the three trials performed in dialysis units together. After our stratification, the Desmyter, Smuzness and Crosnier group appears to be homogeneous (Chi-square = 0.11, degrees of freedom = 2). Our estimates of effectiveness and safety in the high risk group favour treatment, the OR for cases of HB being 0.34; 95% CI (0.21, 0.55). The analysis also revealed a non-significant trend towards benefit in the lower risk health-care workers (Dienstag trial, OR 0.26 (0.05, 1.30). Overall the evidence strongly favours vaccination (OR=0.33; 95% CI (0.21, 0.53)). There was no difference in the incidence and severity of side-effects between the two arms of the trials. We calculated that it was necessary to vaccinate between 145 (assuming a baseline rate of 10 cases/1000/year) and 7 (for a baseline rate of 200/1000/year) health-care workers with plasma-derived vaccines to avoid one case of hepatitis B. Completeness of trial reporting was not good with all four trials failing to report titre results on antibodies against hepatitis B surface antigen and hepatitis B core antigen in the placebo arms (correspondence with two of the four authors failed to shed light on the reasons for such an omission). All four trials achieved low scores in the four quality dimensions assessed (generation of allocation schedule, measure(s) taken to conceal treatment allocation, exclusion of allocated participants from the analysis of the trial and measures taken to implement and protect double blinding). Mean length of follow-up was 14.5 months. REVIEWER'S CONCLUSIONS: Plasma-derived vaccines appear to be efficacious and safe for use in high risk health-care workers, such as staff of renal dialysis and transplant units. There is some uncertainty concerning the effectiveness of the vaccine in lower risk health-care workers, although the trend is towards benefit. We found no evidence of a long-term protective effect due to the short follow-up time of the four trials included in this review. We found relatively poor standard of trial reporting, possibly related to the age of the trials.

Health Personnel↗

Vaccines for preventing cholera.

BACKGROUND: Oral cholera vaccines (either killed whole cell or live recombinant vaccines) are newer alternatives to the parenteral vaccines which have been thought to confer only moderate and short-term immunity. OBJECTIVES: The objective of this review was to assess the effect of cholera vaccines in preventing cases of cholera and preventing deaths. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register, Medline, Embase and reference lists of articles. We handsearched the journal Vaccine, contacted researchers in the field and manufacturers. SELECTION CRITERIA: Randomised and quasi-randomised studies comparing cholera vaccines (killed or live) with placebo, control vaccines or no intervention, or comparing types, doses or schedules of cholera vaccine. We included adults and children irrespective of immune status or special risk category. DATA COLLECTION AND ANALYSIS: Data extraction and assessment of trial quality was done independently by two reviewers. MAIN RESULTS: Thirty-two trials were included. Seventeen efficacy trials of relatively good quality, testing parenteral and oral killed whole cell vaccines and involving over 2. 6 million adults, children and infants were included. Nineteen safety trials have been conducted for both types of killed whole cell vaccines and for live vaccines and have involved 11,459 people. For all types of vaccines compared to placebo, the relative risk of contracting cholera at 12 months was 0.49, 95% confidence interval 0. 41 to 0.59 (random effects model). This translates to an efficacy of 51%, 95% confidence interval 41% to 59%. Both parenteral and oral administration were relatively efficacious, but significant protection extended into the third year for oral killed whole cell vaccines. Children under 5 were only protected for up to a year, while older children or adults were protected for up to three years. Parenteral killed whole cell vaccines were associated with increased systemic and local adverse effects compared to placebo. Oral killed whole cell vaccines or oral live vaccines were not. REVIEWER'S CONCLUSIONS: Cholera killed whole cell vaccines appear to be relatively effective and safe. Live oral recombinant vaccines appear to be safe, but efficacy data are not available. Protection against cholera appears to persist for up to two years following a single dose of vaccine, and for three to four years with an annual booster.

Adult↗

Vaccines for preventing anthrax.

BACKGROUND: Anthrax is an acute bacterial skin disease which may be fatal. Three anthrax vaccines are commercially available but their comparative effectiveness and safety is not clear. OBJECTIVES: The objective of this review was to assess the effects of human anthrax vaccines in healthy adults and children. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, Medline, Embase and the reference lists of articles. We handsearched the journal Vaccine and contacted researchers in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing anthrax vaccines with placebo, vaccines for other diseases or no intervention. DATA COLLECTION AND ANALYSIS: Trial quality assessment and data extraction was conducted independently by the six authors. MAIN RESULTS: Two trials involving 16,052 people were included. Both trials had methodological limitations. Compared to placebo, vaccination was associated with a reduced risk of contracting anthrax (relative risk 0.16, 95% confidence interval 0.07 to 0.35). Compared to placebo, the killed vaccine was associated with a higher incidence and severity of adverse effects (odds ratio 5.15, 95% confidence interval 2.28 to 11.61). Just over 5% of participants in the vaccine group reported adverse effects. The effectiveness of the vaccine does not appear to be influenced by the route of inoculation. REVIEWER'S CONCLUSIONS: Killed anthrax vaccines appear to be effective in reducing the risk of contracting anthrax with a relatively low rate of adverse effects. Further research should be restricted to testing new vaccines only.

Adult↗

Vaccines for preventing plague.

BACKGROUND: Plague is endemic in China, Mongolia, Burma, Vietnam, Indonesia, India, large parts of Southern Africa, the United States and South America. There are three types of vaccines (live attenuated, killed and F1 fraction) with varying means of administration. OBJECTIVES: The objective of this review was to assess the effects of vaccines to prevent plague. SEARCH STRATEGY: We searched Medline, Embase, the Cochrane Controlled Trials Register and reference lists of articles. We handsearched the journal 'Vaccine' and contacted experts in the field. SELECTION CRITERIA: Randomised trials comparing live and killed plague vaccines against no intervention, placebo, other plague vaccines or vaccines against other disease (control vaccines). DATA COLLECTION AND ANALYSIS: Three reviewers assessed the eligibility of trials. MAIN RESULTS: No trials were included. REVIEWER'S CONCLUSIONS: There is not enough evidence to evaluate the effectiveness of any plague vaccine, or the relative effectiveness between vaccines and their tolerability. Circumstantial data from observational studies suggest that killed types may be more effective and have fewer adverse effects than attenuated types of vaccine. No evidence appears to exist on the long-term effects of any plague vaccine.

Humans↗

Vaccines for preventing tick-borne encephalitis.

BACKGROUND: Tick-borne encephalitis is a disease of the central nervous system caused by a virus. Other than the vaccine, there is no treatment for the disease. OBJECTIVES: The objective of this review was to assess the effects of vaccines to prevent tick-borne encephalitis. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Vaccine Fields Trials Register, the Cochrane Controlled Trials Register, Medline, Embase and reference lists of articles. We also handsearched the journal Vaccine. SELECTION CRITERIA: Randomised and quasi-randomised trials comparing tick-borne encephalitis vaccines against placebo, control vaccines or comparisons of different doses or schedules of tick-borne encephalitis vaccines. DATA COLLECTION AND ANALYSIS: Two reviewers independently applied inclusion criteria. A panel of six assessors examined trial quality. MAIN RESULTS: Five trials were included. They could not be combined for meta-analysis because of differences in comparisons and outcomes. Four types of tick-borne encephalitis vaccines were used. All the vaccines gave seroconversion rates of over 87%. There were frequent reports of systemic and local adverse effects. REVIEWER'S CONCLUSIONS: Tick-borne encephalitis vaccines appear to be highly immunogenic, but the relationship between seroconversion and clinical protection has not been established. Although adverse effects were commonly reported, none were severe or life threatening.

Child↗

Amantadine and rimantadine for preventing and treating influenza A in adults.

OBJECTIVES: Amantadine hydrochloride and rimantadine hydrochloride have antiviral properties, but they are not widely used due to a lack of knowledge of their properties and concerns about possible adverse effects. The objective of this review was to assess the effects and safety of amantadine and rimantadine in healthy adults. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, Medline, Embase and reference lists of articles. We also contacted manufacturers, researchers and authors. SELECTION CRITERIA: Randomised and quasi-randomised studies comparing amantadine and/or rimantadine with placebo, control antivirals or no intervention, or comparing doses or schedules of amantadine and/or rimantadine in healthy adults. DATA COLLECTION AND ANALYSIS: For prevention trials the numbers of participants with clinically defined influenza, with serologically confirmed clinical influenza A and adverse effects were analysed. Analysis for treatment trials was of the mean duration of fever and adverse effects. MAIN RESULTS: Amantadine prevented 23% of clinical influenza cases (95% confidence interval 11% to 34%), and 63% of serologically confirmed clinical influenza A cases (95% confidence interval 42% to 76%) Amantadine reduced duration of fever by one day (95% confidence interval 0.7 to 1.3). Rimantadine demonstrated comparable effectiveness, but there were fewer trials and the results for prevention were not statistically significant. Both amantadine and rimantadine induced significant gastrointestinal adverse effects. Adverse effects of the central nervous system adverse and study withdrawals were significantly more common with amantadine than rimantadine. REVIEWER'S CONCLUSIONS: Amantadine and rimantadine have comparable effectiveness in the prevention and treatment of influenza A in healthy adults, although rimantadine induces fewer adverse effects than amantadine.

Adult↗

Neuraminidase inhibitors for preventing and treating influenza in healthy adults.

OBJECTIVES: Influenza is an acute respiratory infection associated with raised temperature, headache, muscle ache and cough. The objective of this review was to assess the effects of neuraminidase inhibitors (NIs) in preventing cases of influenza and shortening or reducing the severity of influenza in healthy adults. A further objective was to estimate the frequency of adverse effects associated with NI administration. SEARCH STRATEGY: We searched Medline, the Cochrane Acute Respiratory Infections Group trials register, the Cochrane Controlled Trials Register (CCTR), manufacturers' databases, Embase (1991 to 1998) and reference lists of articles in May 1999. We also contacted manufacturers, researchers in the field, and authors of studies evaluated in the review. SELECTION CRITERIA: Randomised or quasi-randomised placebo-controlled studies of NIs in healthy adults. Studies assessing protection or treatment from exposure to naturally occurring and experimental influenza were considered. The main outcomes were numbers and/or severity of influenza cases and the number and seriousness of adverse effects. DATA COLLECTION AND ANALYSIS: Two reviewers applied the inclusion criteria to the retrieved studies, assessed trial quality and extracted data. MAIN RESULTS: Eight trials with 1180 adults were included. Overall the methodological quality of the studies appeared to be good. As a preventive measure, NIs when compared to placebo were 74% effective (95% confidence interval 50% to 87%) in preventing naturally occurring cases of clinically defined influenza, and 60% effective (95% confidence interval 76% to 33%) in preventing cases of laboratory confirmed influenza. As a treatment, NIs shorten the duration of symptoms by one day - weighted mean difference 1 (95% confidence interval -1.3 to -0.6). The time gained in returning to normal activities is half a day - weighted mean difference -0.5 ( 95% confidence interval -1.1 to -0.1) for laboratory cases of influenza. The adverse event profile (local nasal irritation) of Zanamivir appears no better than placebo - odds ratio 1.19 ( 95% confidence interval 0.39 to 3.62). Compared with rimantadine in a preventive role, Oseltamivir has a significantly lower incidence of adverse effects and significantly higher incidence of nausea. For treatment, the adverse event profile shows that gastrointestinal symptoms are significantly worse in NIs than placebo - Peto odds ratio 2.32 ( 95% confidence interval 1.55 to 3.47). REVIEWER'S CONCLUSIONS: NIs are effective for the prevention and treatment of influenza. Overall NIs are safe, although Oseltamivir causes significant nausea.

Adult↗

Vaccines for preventing influenza in healthy adults.

OBJECTIVES: To identify, retrieve and assess all studies evaluating the effects of vaccines on influenza in healthy adults. To assess the effectiveness of vaccines in preventing cases of influenza in healthy adults. To estimate the frequency of adverse effects associated with influenza vaccination in healthy adults. SEARCH STRATEGY: MEDLINE was searched using the strategy of the Cochrane Acute Respiratory Infections Group. The bibliography of retrieved articles, the Cochrane Controlled Trials Register (CCTR), and EMBASE (1990 to 1997) were also searched. Handsearch of the journal Vaccine from its first issue to the end of 1997 (Jefferson and Jefferson, 1996; Jefferson, 1998). We wrote to vaccine manufacturers and first or corresponding authors of studies in the review. SELECTION CRITERIA: Any randomised or quasi-randomised studies comparing influenza vaccines in humans with placebo, control vaccines or no intervention, or comparing types, doses or schedules of influenza vaccine. Live, attenuated or killed vaccines or fractions thereof administered by any route, irrespective of antigenic configuration were considered. Only studies assessing protection from exposure to naturally occurring influenza in healthy individuals aged 14 to 60 (irrespective of influenza immune status) were considered. DATA COLLECTION AND ANALYSIS: Both clinically defined cases and serologically confirmed cases of influenza were considered as outcomes according to the authors' definitions. Time off work, complication and hospitalisation rates were considered, together with adverse effects. Vaccine schedules were analysed including one component matching the recommended vaccine (WHO or government recommendations) for the year of the study, and whether they matched the circulating viral subtypes. MAIN RESULTS: The recommended live aerosol vaccines reduced the number of cases of serologically confirmed influenza A by 48% (95% confidence interval 24% to 64%), whilst recommended inactivated parenteral vaccines had a vaccine efficacy of 68% (95% confidence interval 49% to 79%). The vaccines were less effective in reducing clinical influenza cases, with efficacies of 13% and 24% respectively. Use of the vaccine significantly reduced time off work, but only by 0.4 days for each influenza episode (95% confidence interval 0.1 to 0.8 days). Analysis of vaccines matching the circulating strain gave higher estimates of efficacy, whilst inclusion of all other vaccines reduced the efficacy. REVIEWER'S CONCLUSIONS: Influenza vaccines are effective in reducing serologically confirmed cases of influenza A. However, they are not as effective in reducing cases of clinical influenza. The use of WHO recommended vaccines appears to enhance their effectiveness in practice.

Adult↗

Evaluation of the SIMI system, an experimental computerised network for the surveillance of communicable diseases in Italy.

In Italy, the current communicable disease notification system is organised as follows: in each region, Local Health Units (LHU) fill in and forward case report forms (CRF) to the Regional Health Authority, which send aggregated and individual notifications to several central-level institutions. In most regions, all data are recorded manually on hardcopy. Although most relevant data from CRFs are eventually entered into a computerised database at the National Institute of Statistics (ISTAT), the national database is only available 3-4 years later and no data-quality control is performed at that time. To improve the quality and timeliness of notification, in 1994, the Istituto Superiore di Sanità (the National Institute of Health) began to develop an experimental computerised surveillance network for communicable diseases (referred to as 'SIMI'). Specifically, a software was created and distributed to the LHUs and the Regional Health Authorities; staff training was performed; and feedback and analyses of collected data was promoted. SIMI was evaluated in the 13 regions that were participating in 1997 (out of a total of 20 regions in Italy), using criteria commonly used for surveillance systems (i.e., completeness and coherence of data, case definitions, costs, timeliness, and feedback). SIMI was implemented at a limited cost and the data collected were observed to have had a high degree of completeness and internal consistency. The SIMI system has since been adopted for the routine notification of communicable diseases in nearly all regions. Similar evaluations will be necessary for assessing the performance of the various notification systems used across Europe and to include them in a European network.

Communicable Disease Control↗

Relation between experimental and non-experimental study designs. HB vaccines: a case study.

STUDY OBJECTIVE: To examine the relation between experimental and non-experimental study design in vaccinology. DESIGN: Assessment of each study design's capability of testing four aspects of vaccine performance, namely immunogenicity (the capacity to stimulate the immune system), duration of immunity conferred, incidence and seriousness of side effects, and number of infections prevented by vaccination. SETTING: Experimental and non-experimental studies on hepatitis B (HB) vaccines in the Cochrane Vaccines Field Database. RESULTS: Experimental and non-experimental vaccine study designs are frequently complementary but some aspects of vaccine quality can only be assessed by one of the types of study. More work needs to be done on the relation between study quality and its significance in terms of effect size.

Bias↗

Cochrane reviews and systematic reviews of economic evaluations. Amantadine and rimantadine in the prevention and treatment of influenza.

Cochrane reviews provide standardised and regularly updated syntheses of evidence on the effects of healthcare interventions. We present the rationale for, and some of the results of, a Cochrane review of the effects of amantadine and rimantadine in the prevention and treatment of influenza. The estimates of effect will be incorporated into a decision-making model for tackling influenza in healthy adults (i.e. soldiers in the British Army). Our systematic review of the economics of influenza also provides the international context within which economic data can be interpreted and assessed as a preliminary to an economic evaluation comparing alternative prevention and treatment strategies. Systematic reviews provide powerful and relatively inexpensive evidence of effects and tolerability, which is more likely to convince decision-makers than evidence from single studies. Additionally, they can be used to focus clinical trial questions and provide strategic insight regarding the state-of-the-art knowledge of effects and economics of compounds in a specific field.

Adult↗

Morbidity surveillance in the British Army--the first 12 months.

This paper describes the data obtained during the first 12 months of the morbidity surveillance system used, world-wide, by the British Army in operational and non-operational settings and the economic impact of such morbidity in terms of estimated working days lost. Analysis is provided on primary health care and dental morbidity, the surveillance of patients undergoing physiotherapy and those Service personnel cared for by the NHS. The surveillance of the latter population shows a high burden of morbidity which, previously, has never been quantified. The most frequent cause of attendance within primary health care is injuries (all causes) with an annual total of 77,254--a rate per 1,000 personnel per month of 51.92. This leads to an annual loss of manpower, in terms of estimated working days lost of 127,839--a rate per 1,000 personnel per month of 85.91. Army Training Regiments (ATRs-5 sites), Infantry Training Centres (ITCs-2 sites) and the Royal Military Academy Sandhurst (RMAS) are grouped together as Selected Training Establishments (STEs) and show attendance rates higher than the mean for all causes. Summary results of Cochrane systematic reviews presenting up-to-date concise information on experimental evidence as to which preventive interventions should be used to diminish the notable impact of injuries on Army personnel are also given.

Absenteeism↗

J95-EPINATO based planning parameters for medical support to Operations Other Than War (OOTW).

As with increasing frequency the armies of NATO member states deploy on Operations Other Than War (OOTW), there is a requirement to define predictory variables of consumption of healthcare assets by type and geographical location of operations. This report presents the results of the analysis of the J95/EPINATO database of operational and exercise deployments. Although the database is limited in size and scope results show a marked difference in rates of incidence of EVENTS and in the proportion of first attendances to working days lost, both in general and when analysed by deployment type. For instance Service Assisted or Protected Evacuations (SA/PE) showed a relatively high incidence of first attendances and low incidence of working days lost for all reasons (or EVENTS) (214.5 per 1,000 personnel at risk per month-95% Confidence Interval-CI: 198.8 to 230.3 and 23.9 working days lost per 1,000 personnel at risk per month-95% CI 18.0 to 29.8). The reverse is true for Counter Insurgency (COIN) type operations (111.55 per 1,000 personnel at risk per month-95% CI: 110.9 to 112.2 and 161.25 working days lost per 1,000 personnel at risk per month 95% CI: 160.5 to 162.0). Other findings include highest attendance rates in exercise deployments for all reasons (264.7 per 1,000 personnel per month 95% CI: 261.2 to 268.1), highest hospitalisation rates in exercise and PSO deployments for all reasons (8.7 per 1,000 personnel per month 95% CI: 7.9 to 9.4 and 9.9 per 1,000 personnel per month 95% CI: 9.6 to 10.1) and the seasonal pattern, high incidence and low manpower impact (26.2 per 1,000 personnel per month 95% CI: 25.9 to 26.5 and 3.5 per 1,000 personnel per month 95% CI: 3.4 to 3.6) of dermatological consultations on all operational deployments (the lowest of the spectrum being in COIN operations). No relationship was found between incidence of consultations, working days lost, hospitalisations and distance of the deployment from the UK. Deployments to Africa show the highest incident of attendances and working days lost for all reasons (530.7 per 1,000 personnel per month 95% CI: 524.2 to 537.3 and 106.5 per 1,000 personnel per month 95% CI: 102.5 to 110.6). The variability in epidemiological profiles in this analysis demonstrates the dangers of exclusive reliance on synthetic classifications of reasons for attendances such as the traditional DNBI breakdown and on point estimates of incidence. As the database expands, further analysis will become possible.

Databases, Factual↗

Methodological quality of economic modelling studies. A case study with hepatitis B vaccines.

The notable increase in the quantity of economic evaluations in the last 2 decades has not been matched by good methodological standards. This problem is particularly evident in the field of economic evaluations of hepatitis B vaccines. The results of 2 systematic reviews conducted by us in 1993 and 1996 showed three problem areas. A sizeable minority of study reports failed to provide a clear study aim, showing a basic ignorance of the first rule of conducting scientific research. The basic epidemiological assumptions upon which the economic models were based showed variability which persisted even after stratification, raising the question of the accuracy of the epidemiological knowledge base of hepatitis B infection and its progression. Lastly, many of the studies showed weaknesses in basic methods of conducting and reporting economic evaluations. Examination of these problem areas led us to conclude that no conclusions about the efficiency of hepatitis B vaccines could be drawn from the available evidence. Addressing the problem of poor methodological standards concerns the whole research community. However, as a proportion of economic evaluations are published, one obvious means of exerting pressure to increase and maintain methodological standards is the editorial and peer review process. Editors of specialist and general medical journals should agree on and enforce common explicit guidelines for study conduct and reporting, following the example of the British Medical Journal.

Hepatitis B↗

Incidence rates of leukemias, lymphomas and myelomas in Italy: geographic distribution and NHL histotypes.

The annual incidence of non-Hodgkin's lymphomas is increasing by 3 to 4% in different parts of the developed world, while rates for Hodgkin's disease, myelomas and leukemias are more stable. In the case of this group of malignancies, hypothesis generation on risk factors has been limited by the use of the ICD classification in mortality and incidence statistics. We have computed incidence rates in different Italian areas after careful re-classification of diagnoses, and considering specific histotypes (Working Formulation for NHL, Rye's classification for HD). While no particularly interesting pattern is suggested for Hodgkin's disease (even after considering specific Rye subgroups), multiple myeloma and leukemias, for non-Hodgkin's lymphomas the high rate in one agricultural area (Forli) was mainly due to the A sub-group in the Working Formulation (low-grade). In a heavily industrialized area (Varese), the high incidence rate was at least partly explained by a higher proportion of cases classified in the G sub-group (intermediate grade). Excesses of non-Hodgkin's lymphomas have been observed in populations exposed to phenoxy-acetic-acid herbicides, to insecticides and to organic solvents. One can hypothesize that different risk factors act on different stem cells and induce lymphoid malignancies belonging to different histologic sub-types.

Adult↗