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T Jefferson

Publications and source records attributed to T Jefferson.

At least 37 records · Page 2Linked to original sources
PubMed2000

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↗
PubMed2000

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↗
PubMed2000

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↗
PubMed2000

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↗
PubMed2000

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↗
PubMed2000

Population-based study on incidence, risk factors, clinical complications and drug utilisation associated with influenza in the United Kingdom.

This large population-based study using the UK-based General Practice Research Database was conducted to quantify influenza-related physician visits, clinical complications of and risk factors for influenza, and related drug use in all age groups from 1991 to 1996. A total of 141,293 subjects who had one or more diagnoses of influenza or influenza-like illness during the study period as well as the same number of age-, sex-, practice and calendar time-matched controls were identified. Adults aged 15-64 years had the highest influenza incidence rate. The risk of getting influenza was particularly increased for subjects with chronic respiratory conditions (asthma or chronic obstructive pulmonary disease, odds ratio 1.65, 95% confidence interval 1.60-1.70). Subjects with influenza were more likely to have a diagnosis of clinical complications than control subjects (relative risk 3.4, 95% confidence interval 3.3-3.6). The risk of developing clinical complications was highest for children and was elevated for subjects with certain underlying chronic conditions. In absolute terms, otherwise healthy adults (15-64 years) accounted for the greatest proportion of all influenza-related physician visits as well as clinical complications in this study population. Of the 141,293 subjects with influenza, 83,911 (59.4%) received drugs on prescription. The most frequently prescribed drugs were antibiotics (45.2%), followed by antipyretics/analgesics (22.5%). Influenza patients were approximately six times more likely to use drugs on prescription than controls. This analysis may lead to further analyses on the economic impact of influenza and the contribution of different population groups to that burden.

Adolescent↗
PubMed1999

Do vaccines make best use of available resources? (in other words are they cost-effective?).

Vaccines are the most popular preventive intervention world-wide and are socially useful interventions. As with all social programmes, the effects of vaccines must be carefully assessed. Their economic significance lies partly in the burden of disease that can be avoided and partly in the competition for resources between vaccines and other interventions. Classic methods of economic evaluation depend on the evaluation of effectiveness and safety of each vaccine being evaluated and can indicate whether vaccination represent a good return for investment, especially if the wider social perspective is taken into account. The use of economic logic can also be applied to prioritize research into vaccines, both on the basis of ability of the target population to benefit and of the availability of good quality evidence.

Cost-Benefit Analysis↗
PubMed1999

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↗
PubMed1999

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↗
PubMed1998

Evaluating the BMJ guidelines for economic submissions: prospective audit of economic submissions to BMJ and The Lancet.

CONTEXT: Editorial management of articles on health economics may benefit from guidelines for peer review and revision. OBJECTIVE: To assess whether publication (in August 1996) of the BMJ guidelines on peer review of economics submissions made any difference to editorial and peer review processes, quality of submitted manuscripts, and quality of published manuscripts. DESIGN AND SETTING: Before-after study conducted in the editorial offices of BMJ and The Lancet of the effect of the BMJ guidelines on review and revision of economics submissions, defined as those making explicit comments about resource allocation and/or costs of interventions. MAIN OUTCOME MEASURES: Editorial fate and changes in the quality of submissions. RESULTS: A total of 2982 manuscripts were submitted to the 2 journals during the before periods, 105 (3.5%) of which were economics submissions. Of these, 27 (24.3%) were full economics evaluations, and 78 (75.7%) were other economics submissions. Overall acceptance rate was 11.6% (12/105). During the after period 2077 manuscripts were submitted to the 2 journals, 87 (4.2%) of which were economics submissions. Eighteen (20.7%) were full economics evaluations, and 69 (79.3%) were other economics submissions. Overall acceptance rate was 6.9% (6/87). Although a number of manuscripts could not be traced to determine whether they were economics submissions, there appeared to be little difference between the 2 journals in numbers or editorial fate of the manuscripts. There was no change in the quality of submitted manuscripts, but BMJ editors found the guidelines and checklists useful and sent fewer economics submissions for external peer review in the after phase. CONCLUSIONS: Publication of the guidelines helped the BMJ editors improve the efficiency of the editorial process but had no impact on the quality of economics evaluations submitted or published.

Economics↗