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Biomedical subjects

T Jefferson

Publications and source records attributed to T Jefferson.

At least 19 recordsLinked to original sources
PubMed2006

Vaccines for preventing influenza in the elderly.

BACKGROUND: Influenza vaccination of elderly individuals is recommended worldwide and has been targeted toward the elderly and those at serious risk of complications. OBJECTIVES: Our aim was to review the evidence of efficacy, effectiveness and safety of influenza vaccines in individuals aged 65 years or older. SEARCH STRATEGY: We searched the following databases on The Cochrane Library, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effectiveness (Issue 1, 2006); MEDLINE (January 1966 to March Week 3 2006); EMBASE (Dialog 1974 to 1979; SilverPlatter 1980 to December 2005); Biological Abstracts (SilverPlatter 1969 to December 2004); and Science Citation Index (Web of Science 1974 to December 2004). SELECTION CRITERIA: We considered randomised, quasi-randomised, cohort and case-control studies assessing efficacy against influenza (laboratory-confirmed cases) or effectiveness against influenza-like illness (ILI) or safety. Any influenza vaccine given independently, in any dose, preparation or time schedule, compared with placebo or with no intervention was considered. DATA COLLECTION AND ANALYSIS: We grouped reports first according to the setting of the study (community or long-term care facilities) and then by level of viral circulation and vaccine matching. We further stratified by co-administration of pneumococcal polysaccharide vaccine (PPV) and by different types of influenza vaccines. We analysed the following outcomes: influenza, influenza-like illness, hospital admissions, complications and deaths. MAIN RESULTS: Sixty-four studies were included in the efficacy / effectiveness assessment, resulting in 96 data sets. In homes for elderly individuals (with good vaccine match and high viral circulation) the effectiveness of vaccines against ILI was 23% (6% to 36%) and non-significant against influenza (RR 1.04: 95% CI 0.43 to 2.51). We found no correlation between vaccine coverage and ILI attack rate. Well matched vaccines prevented pneumonia (VE 46%; 30% to 58%), hospital admission (VE 45%; 16% to 64%) and deaths from influenza or pneumonia (VE 42%, 17% to 59%). In elderly individuals living in the community, vaccines were not significantly effective against influenza (RR 0.19; 95% CI 0.02 to 2.01), ILI (RR 1.05: 95% CI 0.58 to 1.89), or pneumonia (RR 0.88; 95% CI 0.64 to 1.20). Well matched vaccines prevented hospital admission for influenza and pneumonia (VE 26%; 12% to 38%) and all-cause mortality (VE 42%; 24% to 55%). After adjustment for confounders, vaccine performance was improved for admissions to hospital for influenza or pneumonia (VE* 27%; 21% to 33%), respiratory diseases (VE* 22%; 15% to 28%) and cardiac disease (VE* 24%; 18% to 30%); and for all-cause mortality (VE* 47%; 39% to 54%). The public health safety profiles of the vaccines appear to be acceptable. AUTHORS' CONCLUSIONS: In long-term care facilities, where vaccination is most effective against complications, the aims of the vaccination campaign are fulfilled, at least in part. However, according to reliable evidence the usefulness of vaccines in the community is modest. The apparent high effectiveness of the vaccines in preventing death from all causes may reflect a baseline imbalance in health status and other systematic differences in the two groups of participants.

Aged↗
PubMed2006

Influenza vaccination for healthcare workers who work with the elderly.

BACKGROUND: Healthcare workers (HCW) (nurses, doctors, other health professionals, cleaners and porters), have substantial rates of clinical and sub-clinical influenza during influenza seasons and may transmit influenza to those in their care, especially the vulnerable elderly. OBJECTIVES: To identify and summarise comparative studies assessing the effects of vaccinating healthcare workers (HCW) on the incidence of influenza, influenza-like-illness (ILI) and its complications on elderly residents in long-term facilities. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Database of Systematic Reviews and the NHS Database of Abstracts of Reviews of Effectiveness (DARE) (The Cochrane Library Issue 1, 2006); MEDLINE (January 1966 to Week 1, February 2006); EMBASE (1974 to March 2006); Biological Abstracts (1969 to December 2004); and Science Citation Index-Expanded (1974 to March 2006). SELECTION CRITERIA: Comparative randomised and non-randomised studies reporting the effects of influenza vaccines on the incidence of viral infections in institutions for the elderly of any type, in any schedule of vaccination given to HCW caring for elderly residents of long-term facilities aged 60 years or older. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data and assessed the methodological quality using criteria from the Cochrane Reviewers' Handbook and the Newcastle-Ottawa scale (for non-randomised studies). MAIN RESULTS: We included two cluster randomised controlled trials (C-RCT) and one cohort study. Staff vaccination appears to have significant effect against ILI (absolute vaccine efficacy (VE) 86%, 95% confidence interval (CI) 40% to 97%) only when patients are vaccinated too; if patients are not vaccinated, staff immunisation shows no effect (based on one C-RCT). Based on a small number of observations from two C-RCTs, the vaccines have no efficacy against influenza (odds ratio (OR) 0.86, 95% CI 0.44 to 1.68) or lower respiratory tract infections (OR 0.70, 95% CI 0.41 to 1.20) but were effective against deaths from pneumonia (VE 39%, 95% CI 2% to 62%) and deaths from all causes (VE 40%, 95% CI 27% to 50%). All findings must be interpreted with caution given the presence of selection bias. AUTHORS' CONCLUSIONS: We concluded that there is no credible evidence that vaccination of healthy people under the age of 60, who are HCWs caring for the elderly, affects influenza complications in those cared for. However, as vaccinating the elderly in institutions reduces the complications of influenza and vaccinating healthy persons under 60 reduces cases of influenza, those with the responsibility of caring for the elderly in institutions may want to increase vaccine coverage and assess its effects in well-designed studies.

Adult↗
PubMed2006

Amantadine and rimantadine for influenza A in adults.

BACKGROUND: Amantadine hydrochloride and rimantadine hydrochloride have antiviral properties, but they are not widely used due to a lack of knowledge of their potential value and concerns about possible adverse effects. OBJECTIVES: The objective of this review was to assess the efficacy, effectiveness and safety ("effects") of amantadine and rimantadine in healthy adults. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2005), MEDLINE (2003 to August Week 4, 2005), EMBASE (October 2003 to July 2005) and reference lists of articles. SELECTION CRITERIA: Randomised and quasi-randomised studies comparing amantadine and/or rimantadine with placebo, control medication or no intervention, or comparing doses or schedules of amantadine and/or rimantadine in healthy adults. DATA COLLECTION AND ANALYSIS: For prophylaxis (prevention) trials the numbers of participants with clinical influenza (influenza-like-illness or ILI) or with confirmed influenza A and adverse effects were analysed. Analysis for treatment trials was of the mean duration of fever, length of hospital stay and adverse effects. MAIN RESULTS: Amantadine prevented 25% of ILI cases (95% confidence interval (CI) 13% to 36%), and 61% of influenza A cases (95% CI 35% to 76%). Amantadine reduced duration of fever by one day (95% CI 0.7 to 1.2). Rimantadine demonstrated comparable effectiveness, but there were fewer trials and the results for prophylaxis were not statistically significant. Both amantadine and rimantadine induced significant gastrointestinal adverse effects. Adverse effects of the central nervous system and study withdrawals were significantly more common with amantadine than rimantadine. Neither drug affected the rate of viral shedding from the nose and the course of asymptomatic influenza. AUTHORS' CONCLUSIONS: Amantadine and rimantadine have comparable efficacy and effectiveness in relieving or treating symptoms of influenza A in healthy adults, although rimantadine induces fewer adverse effects than amantadine. The effectiveness of both drugs in interrupting transmission is probably low. Routine use of both drugs should be discouraged and both drugs should only be used when all other measures fail.

Adult↗
PubMed2006

Antivirals for influenza in healthy adults: systematic review.

BACKGROUND: Use of antivirals is recommended for the control of seasonal and pandemic influenza. Our aim was to review the evidence of efficacy, effectiveness, and safety of registered antivirals against naturally occurring influenza in healthy adults. METHODS: We searched various Databases to October, 2005, and contacted manufacturers and corresponding authors. We included randomised controlled trials comparing prophylactic (n=27) or treatment (n=27) efficacy against symptomatic or asymptomatic influenza. We did a meta-analysis and expressed prophylactic efficacy as a proportion (1-relative risk [RR]). For treatment trials, because of inconsistent and non-standardised reporting, we expressed continuous outcomes either as means or as hazard ratios. FINDINGS: We included 51 reports of 52 randomised controlled trials. Amantadine prevented 61% (95% CI 35-76) of influenza A cases and 25% (13-36) of cases of influenza-like illness, but caused nausea (OR 2.56, 1.37-4.79), insomnia and hallucinations (2.54, 1.50-4.31), and withdrawals because of adverse events (2.54, 1.60-4.06). There was no effect on asymptomatic cases (RR 0.85, 0.40-1.80). In treatment, amantadine significantly shortened duration of fever compared with placebo (by 0.99 days, -1.26 to -0.71), but had no effect on nasal shedding of influenza A viruses (0.93, 0.71-1.21). The fewer data for rimantadine showed comparable effects. In prophylaxis, compared with placebo, neuraminidase inhibitors have no effect against influenza-like illness (1.28, 0.45-3.66 for oral oseltamivir 75 mg daily, 1.51, 0.77-2.95 for inhaled zanamivir 10 mg daily). Higher doses appear to make no difference. The efficacy of oral oseltamivir 75 mg daily against symptomatic influenza is 61% (15-82), or 73% (33-89) at 150 mg daily. Inhaled zanamivir 10 mg daily is 62% efficacious (15-83). Neither neuraminidase inhibitor appeared effective against asymptomatic influenza. Oseltamivir induces nausea (OR 1.79, 1.10-2.93), especially at higher prophylactic doses (2.29, 1.34-3.92). Oseltamivir in a post-exposure prophylaxis role has a protective efficacy of 58.5% (15.6-79.6) for households and from 68% (34.9-84.2) to 89% (67-97) in contacts of index cases. In influenza cases, compared with placebo the hazard ratios for time to alleviation of symptoms were 1.33, 1.29-1.37 for zanamivir; 1.30, 1.13-1.50 for oseltamivir provided medication was started within 48 h of symptom onset. Viral nasal titres were significantly diminished by both drugs (weighted mean difference -0.62, -0.82 to -0.41). Oseltamivir at 150 mg daily was effective in preventing lower respiratory tract complications in influenza cases (OR 0.32, 0.18-0.57). We could find no credible data on the effects of oseltamivir on avian influenza. INTERPRETATION: The use of amantadine and rimantadine should be discouraged. Because of their low effectiveness, neuraminidase inhibitors should not be used in seasonal influenza control and should only be used in a serious epidemic or pandemic alongside other public-health measures.

Adolescent↗
PubMed2006

Vaccines for preventing influenza in healthy children.

BACKGROUND: In children and adults the consequences of influenza are mainly absences from school and work, however the risk of complications is greatest in children and people over 65 years old. OBJECTIVES: To appraise all comparative studies evaluating the effects of influenza vaccines in healthy children; assess vaccine efficacy (prevention of confirmed influenza) and effectiveness (prevention of influenza-like illness) and document adverse events associated with receiving influenza vaccines. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005); OLD MEDLINE (1966 to 1969); MEDLINE (1969 to December 2004); EMBASE (1974 to December 2004); Biological Abstracts (1969 to December 2004); and Science Citation Index (1974 to December 2004). We wrote to vaccine manufacturers and a number of corresponding authors of studies in the review. SELECTION CRITERIA: Any randomised controlled trials (RCTs), cohort and case-control studies of any influenza vaccine in healthy children under 16 years old. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. MAIN RESULTS: Fifty-one studies involving 263,987 children were included. Seventeen papers were translated from Russian. Fourteen RCTs and 11 cohort studies were included in the analysis of vaccine efficacy and effectiveness. From RCTs, live vaccines showed an efficacy of 79% (95% confidence interval (CI) 48% to 92%) and an effectiveness of 33% (95% CI 28% to 38%) in children older than two years compared with placebo or no intervention. Inactivated vaccines had a lower efficacy of 59% (95% CI 41% to 71%) than live vaccines but similar effectiveness: 36% (95% CI 24% to 46%). In children under two, the efficacy of inactivated vaccine was similar to placebo. Thirty-four reports containing safety outcomes were included, 22 including live vaccines, 8 inactivated vaccines and 4 both types. The most commonly presented short-term outcomes were temperature and local reactions. The variability in design of studies and presentation of data was such that meta-analysis of safety outcome data was not feasible. AUTHORS' CONCLUSIONS: Influenza vaccines are efficacious in children older than two years but little evidence is available for children under two. There was a marked difference between vaccine efficacy and effectiveness. That no safety comparisons could be carried out emphasizes the need for standardisation of methods and presentation of vaccine safety data in future studies. It was surprising to find only one study of inactivated vaccine in children under two years, given recent recommendations to vaccinate healthy children from six months old in the USA and Canada. If immunisation in children is to be recommended as public-health policy, large-scale studies assessing important outcomes and directly comparing vaccine types are urgently required.

Adolescent↗
PubMed2005

Vaccines for measles, mumps and rubella in children.

BACKGROUND: Public debate over the safety of the trivalent measles, mumps and rubella (MMR) vaccine, and the resultant drop in vaccination rates in several countries, persists despite its almost universal use and accepted effectiveness. OBJECTIVES: We carried out a systematic review to assess the evidence of effectiveness and unintended effects associated with MMR. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to December 2004), EMBASE (1974 to December 2004), Biological Abstracts (from 1985 to December 2004), and Science Citation Index (from 1980 to December 2004). Results from reviews, handsearching and from the consultation of manufacturers and authors were also used. SELECTION CRITERIA: Eligible studies were comparative prospective or retrospective trials testing the effects of MMR compared to placebo, do-nothing or a combination of measles, mumps and rubella antigens on healthy individuals up to 15 years of age. These studies were carried out or published by 2004. DATA COLLECTION AND ANALYSIS: We identified 139 articles possibly satisfying our inclusion criteria and included 31 in the review. MAIN RESULTS: MMR was associated with a lower incidence of upper respiratory tract infections, a higher incidence of irritability, and similar incidence of other adverse effects compared to placebo. The vaccine was likely to be associated with benign thrombocytopenic purpura, parotitis, joint and limb complaints, febrile convulsions within two weeks of vaccination and aseptic meningitis (mumps) (Urabe strain-containing MMR). Exposure to MMR was unlikely to be associated with Crohn's disease, ulcerative colitis, autism or aseptic meningitis (mumps) (Jeryl-Lynn strain-containing MMR). We could not identify studies assessing the effectiveness of MMR that fulfilled our inclusion criteria even though the impact of mass immunisation on the elimination of the diseases has been largely demonstrated. AUTHORS' CONCLUSIONS: The design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate. The evidence of adverse events following immunisation with MMR cannot be separated from its role in preventing the target diseases.

Adolescent↗
PubMed2005

Efficacy and effectiveness of influenza vaccines in elderly people: a systematic review.

BACKGROUND: Influenza vaccination of elderly individuals is recommended worldwide. Our aim was to review the evidence of efficacy and effectiveness of influenza vaccines in individuals aged 65 years or older. METHODS: We searched five electronic databases to December, 2004, in any language, for randomised (n=5), cohort (n=49), and case-control (n=10) studies, assessing efficacy against influenza (reduction in laboratory-confirmed cases) or effectiveness against influenza-like illness (reduction in symptomatic cases). We expressed vaccine efficacy or effectiveness as a proportion, using the formula VE=1-relative risk (RR) or VE*=1-odds ratio (OR). We analysed the following outcomes: influenza, influenza-like illness, hospital admissions, complications, and deaths. FINDINGS: In homes for elderly individuals (with good vaccine match and high viral circulation) the effectiveness of vaccines against influenza-like illness was 23% (95% CI 6-36) and non-significant against influenza (RR 1.04, 0.43-2.51). Well matched vaccines prevented pneumonia (VE 46%, 30-58) and hospital admission (VE 45%, 16-64) for and deaths from influenza or pneumonia (VE 42%, 17-59), and reduced all-cause mortality (VE 60%, 23-79). In elderly individuals living in the community, vaccines were not significantly effective against influenza (RR 0.19, 0.02-2.01), influenza-like illness (RR 1.05, 0.58-1.89), or pneumonia (RR 0.88, 0.64-1.20). Well matched vaccines prevented hospital admission for influenza and pneumonia (VE 26%, 12-38) and all-cause mortality (VE 42%, 24-55). After adjustment for confounders, vaccine performance was improved for admissions to hospital for influenza or pneumonia (VE* 27%, 21-33), respiratory diseases (VE* 22%, 15-28), and cardiac disease (VE* 24%, 18-30), and for all-cause mortality (VE* 47%, 39-54). INTERPRETATION: In long-term care facilities, where vaccination is most effective against complications, the aims of the vaccination campaign are fulfilled, at least in part. However, according to reliable evidence the usefulness of vaccines in the community is modest.

Aged↗
PubMed2004

Methodological issues arising from systematic reviews of the evidence of safety of vaccines.

Adaptations to the recognized methods of systematic reviewing are required when addressing questions about safety, particularly about rare and/or long-term serious adverse events. Conducting a systematic review of vaccine safety requires the implementation of novel strategies for locating studies, the use of experimental instruments to assess the quality of non-randomized studies, and the employment of pooling methods for non-randomized data, where appropriate. Standardizing both the indexing of adverse event data on electronic libraries and their reporting would improve the potential of systematic reviews of vaccine to draw accurate conclusions about the safety of a vaccine.

Data Interpretation, Statistical↗
PubMed2004

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

BACKGROUND: Amantadine hydrochloride and rimantadine hydrochloride have antiviral properties, but these drugs are not widely used due to a lack of knowledge of their potential value and concerns about possible adverse effects. OBJECTIVES: The objective of this review was to assess the effectiveness and safety ("effects") of amantadine and rimantadine in healthy adults. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2003), MEDLINE (January 1966 to November week 2, 2003), EMBASE (January 1990 to September 2003) and the 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 clinical influenza (influenza-like-illness or ILI), i.e. confirmed influenza A, and adverse effects were analysed. Analysis for treatment trials included the mean duration of fever and length of hospital stay, and the number of adverse effects. MAIN RESULTS: Amantadine prevented 25% of ILI cases (95% confidence interval (CI) 13% to 36%), and 61% of influenza A cases (95% CI 35% to 76%). Amantadine reduced duration of fever by one day (95% CI 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 and study withdrawals were significantly more common with amantadine than rimantadine. REVIEWERS' CONCLUSIONS: Amantadine and rimantadine have comparable effectiveness in the prevention and treatment of influenza A in healthy adults, although rimantadine causes fewer adverse effects than amantadine.

Adult↗
PubMed2004

Effectiveness of immune globulins in preventing infectious hepatitis and hepatitis A: a systematic review.

OBJECTIVE: To assess the effectiveness and safety of immune globulins in preventing infectious hepatitis and hepatitis A. STUDY DESIGN: Systematic review with meta-analysis. DATA SOURCES: We searched the Cochrane Library, MEDLINE, EMBASE, Biological Abstracts and Science Citation Index to December 2002. Vaccine manufacturers were contacted for additional data. REVIEW METHODS: We included randomised controlled trials comparing effectiveness of hepatitis A immune globulins with no intervention or placebo, and carried out a meta-analysis. RESULTS: We included six studies (two in Russian). Tested immune globulins show higher effectiveness than placebo or do-nothing against infectious hepatitis both in primary prevention and in prevention after exposure (effectiveness 83%; RR: 0.17; 95% CI: 0.15-0.19; and effectiveness 69%; RR: 0.31; 95% CI: 0.20-0.47, respectively). We found considerable heterogeneity among studies, possibly due to different methodology, background rates of disease and immune globulins dosage and concentrations. No safety data were reported in the studies. CONCLUSIONS: Immune globulins are efficacious in preventing infectious hepatitis and hepatitis A, but included studies do not report data about their safety. Average length of passive protection was three months. Given the notable heterogeneity of performance of immune globulins, short protection conferred and absence of trial safety data, the only indications for the use of immune globulins may be in situations in which inadequate supplies of vaccine are available or when the eight-day window of opportunity for vaccine use is past.

Chi-Square Distribution↗
PubMed2002

Influenza vaccines in adults.

Available influenza vaccines contain inactivated viruses, either whole or in parts, and are administered parenterally or intranasally. Their composition varies yearly because of viral antigenic shifts and drifts. Vaccines with a composition matching yearly World Health Organization recommendations are 72% [95% confidence interval (CI) = 54-83%] efficacious (prevention of influenza cases caused by influenza viruses A and B). Their effectiveness [capacity to prevent clinical influenza, or influenza-like illness (ILI)] is lower, at 37% (95% CI = 18-52%). A decision to vaccinate an adult population has to take into account the efficacy of the vaccines and their effectiveness (the likely proportion of ILI caused by influenza A and B viruses, amenable to prevention by vaccination), as well as costs and likely compliance. As the yearly levels of circulating A and B viruses are difficult to predict during the decision time for a vaccination campaign, there is a considerable element of uncertainty regarding the likely effectiveness of 'this year's' vaccine.

Adolescent↗
PubMed2001

Vaccine safety--improving monitoring.

The growing numbers of vaccines and vaccine combinations make monitoring of vaccine safety increasingly complex. At the same time, health agencies and the public request better information on the safety of vaccines. The following steps should be taken to improve monitoring of vaccine safety: bar code labelling of vaccines to improve accuracy and completeness of information on administered vaccines, establishing immunisation registers to provide numerator data on exposure to vaccines, to facilitate long term follow-up and to do linked database studies. Development of improved case definitions to increase comparability between studies. Organising systematic assessments of all information on suspect or alleged vaccine reactions.

Databases, Factual↗
PubMed2001

Demyelinating disease and hepatitis B vaccination: is there a link?

The recent decision by the French government to compensate 3 recipients of hepatitis B vaccine preceding the onset of multiple sclerosis presumes a possible causal link and brings into question the use of current rules of causality assessment. Available evidence does not support a causal link or is equivocal but the accuracy of current methods of vaccine surveillance should be urgently improved. Larger and longer randomised trials, updated summaries of evidence, linked databases, prospective vaccination registers, bar-coding of vaccines and standardisation of adverse event definitions are possible measures to address current problems.

Evidence-Based Medicine↗
PubMed2000

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↗
PubMed2000

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↗