vittorio demicheli - Academia.edu (original) (raw)

Papers by vittorio demicheli

Research paper thumbnail of The effectiveness and safety of hepatitis A vaccine: a systematic review

Vaccine, 2003

We report on the conduct of a systematic review to assess the efficacy and the safety of hepatiti... more We report on the conduct of a systematic review to assess the efficacy and the safety of hepatitis A vaccines in adults and children. We identified, retrieved, and assessed all trials evaluating the effects of hepatitis A vaccines on prevention of cases of hepatitis A, death from hepatitis A, and assessing nature and frequency of adverse events. We included eight randomised trials, four containing efficacy outcomes, three containing only safety outcomes and a single study containing efficacy and adverse events outcomes. Combined inactivated vaccine effectiveness was 86% (95% CI: 63-95%). Combined attenuated vaccine effectiveness was 95% (95% CI: 81-99%). Inactivated vaccine effectiveness in the prevention of HAV secondary cases, compared to non-intervention was 82% (95% CI: 23-96%). Safety profile of vaccines was similar to that of their comparators. Despite poor design and reporting of trials, we found convincing evidence of the effectiveness and safety of inactivated HAV vaccines.

Research paper thumbnail of The use of hepatitis a vaccination in Italy: an economic evaluation

Vaccine, 2003

We report on the conduct and results of an economic model of two different strategies of vaccinat... more We report on the conduct and results of an economic model of two different strategies of vaccination against hepatitis A in Italy. In strategy 1 (universal vaccination), all newborns are vaccinated simultaneously with MMR at 15 months and all 12 year olds are vaccinated with combined hepatitis A and B vaccine. In strategy 2 (contacts' vaccination) only subjects with a close social and spatial relationship with the sick are vaccinated.

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

European Journal of Epidemiology, 2000

In Italy, the current communicable disease notification system is organised as follows: in each r... more 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 hard-copy. 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.

Research paper thumbnail of Incidence of vaccine preventable pneumococcal invasive infections and blood culture practices in Italy

Research paper thumbnail of Economic aspects of a small epidemic of hepatitis A in a religious community in Northern Italy

Journal of Infection, 1996

We report on a small (11 cases) outbreak of hepatitis A (HA) which occurred in the village of Nar... more We report on a small (11 cases) outbreak of hepatitis A (HA) which occurred in the village of Narzole in the province of Cuneo, Northern Italy. Cases were reported during the period December 1993-March 1994 and centred around a Christian community centre caring for broken homes. Eight cases were children aged 7-13 and three were adults. The incidence for all ages was 354.8 per 100 000 inhabitants. Due to local resistance to the investigation of the outbreak we were unable to identify the source of the outbreak.

Research paper thumbnail of The effectiveness and safety of vaccines against human anthrax: a systematic review

Vaccine, 1998

We report on the results of a systematic review of existing controlled clinical trials undertaken... more We report on the results of a systematic review of existing controlled clinical trials undertaken to assess the effectiveness and safety of vaccines against human anthrax in relation to disease incidence and side-effects. Two articles retrieved by electronic and hand search fulfilling some of the inclusion criteria underwent a quality assessment by a group of reviewers. Data synthesized from the two trials showed that estimates of overall effectiveness and safety favour treatment (overall odds ratio 0.16; 95% confidence interval 0.07-0.34). The route of inoculation appears to make little difference to the effectiveness of the vaccines; however, one study shows that the incidence and severity of side-effects are significantly higher with the killed vaccine than with the alum-based placebo (overall odds ratio 0.16; 95% confidence interval 2. 38-27.17).

Research paper thumbnail of Prevention and early treatment of influenza in healthy adults

Vaccine, 2000

We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a ... more We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a dierent in¯uenza 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 eects of these interventions in prophylaxis and early treatments of in¯uenza and the frequency of adverse events. Additionally we present the results of the economic evaluation of eective alternatives in order to de®ne the most cost-eective intervention. The economic evaluation is set in the context of the British Army.

Research paper thumbnail of Is vaccination against hepatitis b efficient? A review of world literature

Health Economics, 1994

We report on the result of a study aimed at assessing the variability of assumptions upon which e... more We report on the result of a study aimed at assessing the variability of assumptions upon which economic models for the introduction of vaccination against Hepatitis B are based, the conclusions reached and define a minimum set of methodological standards upon which future economic studies on vaccines should be based. We identified 116 published and unpublished works by Medline literature searches, consulting private databases and corresponding with all authors and researchers active in economic evaluation of vaccines.All works were assessed but we included in our review only those which were original economic analyses (90 studies). Principal epidemiological and economic variables were extracted and compared where possible. Rough manipulations were carried out to make the data comparable. We found profound variability on the main parameters of the efficiency equation (disease incidence, costing methods, use of marginal theory, discounting and study timespan, sensitivity analysis and reporting methods). We also found inconsistencies in definition and study design in 38% of a subset of studies. Although we found scarce decision-making impact, we believe that due to uncertain or unclear methodology, few studies reach valid conclusions. In future decisions may be based on biased evidence and scarce resources committed to untested programmes. There is an urgent need to standardise study methods and define a common set of procedures.

Research paper thumbnail of Hepatitis B vaccination and multiple sclerosis: evidence from a systematic review

Journal of Viral Hepatitis, 2003

An association between administration of hepatitis B vaccine (HBV) and onset or relapse of multip... more An association between administration of hepatitis B vaccine (HBV) and onset or relapse of multiple sclerosis (MS) and other demyelinating diseases (DD) surfaced in the mid-1990s and led to an increase of studies investigating the association. Evidence from these studies, gathered within a systematic review of evidence of safety of HBV is presented. Nine published and two unpublished comparative studies identified in the Cochrane Library, MEDLINE, Embase, Current Contents, Gateway Mesh, Cinhail, Biological Abstracts and Science Citation Index and correspondence with manufacturers and researchers have been included [1][2][3][4][5][6][7][8][9][10][11]. Search strategies combined Mesh and free-text terms for study design, vaccine and DD for the period 1979-2001. Studies of noncomparative design or those not testing the association have been excluded.

Research paper thumbnail of Assessment of the efficacy and effectiveness of influenza vaccines in healthy children: systematic review

Lancet, 2005

Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inact... more Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inactivated influenza vaccines in children up to 16 years of age.

Research paper thumbnail of No evidence that vaccines cause insulin dependent diabetes mellitus

Journal of Epidemiology and Community Health, 1998

Histological and serological findings in insulin dependent diabetes mellitus (IDDM) are consisten... more Histological and serological findings in insulin dependent diabetes mellitus (IDDM) are consistent with autoimmune causes and recent work suggests polygenic inheritance. The incidence in developed countries seems to be increasing, 1 although it is unclear whether this finding is real or artefactual. Given the age of the victims of IDDM and marked diVerences in incidence of the disease in children under 15 1 (see table 1), international attention has began focusing on the nature of possible external stimuli in the genesis of IDDM. Among these, vaccination schedules have been also called into question as possible modulating factors. Classen and Classen have postulated a protective eVect of exposure to immunogens if babies are vaccinated within 42 days from birth. 2 It is known that genetic manipulation in animal models followed by early challenge with vaccine antigen can precipitate onset of Table 1 Incidence of insulin dependent diabetes mellitus in children under 15 years of age from registers of selected worldwide countries. Incidence estimates are derived from national or subnational registers. After Karvonen et al 1 Region Country Study period Incidence rates per 100 000

Research paper thumbnail of Evidence-based vaccinology: the work of the Cochrane Vaccines Field

Journal of Epidemiology and Community Health, 1998

Research paper thumbnail of An exercise on the feasibility of carrying out secondary economic analyses

Health Economics, 1996

Purchasers of health services need up to date information on cost-effectiveness of interventions ... more Purchasers of health services need up to date information on cost-effectiveness of interventions to help in prioritising spending. But economists have not yet developed a formal methodology for reviewing and summing up evidence from individual economic evaluations which may have been conducted at different times and in different places, or indeed for assessing whether such systematic reviews are possible in this context. This paper discusses the problems of reviewing available economic information, using a body of literature on the economics of influenza vaccination to illustrate some relevant issues. First, the paper examines alternative methods for adjusting prices to take into account differences in currency and time periods: Retail Price Indices are compared with health specific inflation indices, and exchange rates are compared with Purchasing Power Parity (PPP) data. For the studies reviewed, the choice of conversion method made little practical difference. Secondly, the paper explores the possibility of summarising the results of a review in terms of quantities of resources used, rather than prices. This method is constrained by the available data, but could be more generally useful as it allows direct comparison of underlying technologies, and calculation of costs by attaching local unit costs to the resources associated with an intervention. These two exercises highlight many of the problems that arise in generalising from economic studies. Both methods need to be developed further if they are to be useful to decision makers.

Research paper thumbnail of Assessment of the efficacy and effectiveness of influenza vaccines in healthy children: systematic review

Lancet, 2005

Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inact... more Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inactivated influenza vaccines in children up to 16 years of age.

Research paper thumbnail of Efficacy and effectiveness of influenza vaccines in elderly people: a systematic review

Lancet, 2005

Background Influenza vaccination of elderly individuals is recommended worldwide. Our aim was to ... more 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.

Research paper thumbnail of Antivirals for influenza in healthy adults: systematic review

Lancet, 2006

Background Use of antivirals is recommended for the control of seasonal and pandemic influenza. O... more 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.

Research paper thumbnail of Unintended events following immunization with MMR: a systematic review

Vaccine, 2003

Public debate over the safety of the trivalent measles, mumps and rubella (MMR) vaccine and the d... more Public debate over the safety of the trivalent measles, mumps and rubella (MMR) vaccine and the drop in vaccination rates in several countries persists despite its almost universal use and accepted effectiveness. We carried out a systematic review to assess the evidence of unintended effects (beneficial or harmful) associated with MMR and the applicability of systematic reviewing methods to the field of safety evaluation. Eligible studies were comparative prospective or retrospective on healthy individuals up to 15 years of age, carried out or published by 2003.

Research paper thumbnail of Relation between experimental and non-experimental study designs. HB vaccines: a case study

Journal of Epidemiology and Community Health, 1999

Study objective-To examine the relation between experimental and nonexperimental study design in ... more Study objective-To examine the relation between experimental and nonexperimental 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 eVects, and number of infections prevented by vaccination.

Research paper thumbnail of Relation of study quality, concordance, take home message, funding, and impact in studies of influenza vaccines: systematic review

British Medical Journal, 2009

To explore the relation between study concordance, take home message, funding, and dissemination ... more To explore the relation between study concordance, take home message, funding, and dissemination of comparative studies assessing the effects of influenza vaccines. Systematic review without meta-analysis. Search of the Cochrane Library, PubMed, Embase, and the web, without language restriction, for any studies comparing the effects of influenza vaccines against placebo or no intervention. Abstraction and assessment of quality of methods were carried out. We identified 259 primary studies (274 datasets). Higher quality studies were significantly more likely to show concordance between data presented and conclusions (odds ratio 16.35, 95% confidence interval 4.24 to 63.04) and less likely to favour effectiveness of vaccines (0.04, 0.02 to 0.09). Government funded studies were less likely to have conclusions favouring the vaccines (0.45, 0.26 to 0.90). A higher mean journal impact factor was associated with complete or partial industry funding compared with government or private funding and no funding (differences between means 5.04). Study size was not associated with concordance, content of take home message, funding, and study quality. Higher citation index factor was associated with partial or complete industry funding. This was sensitive to the exclusion from the analysis of studies with undeclared funding. Publication in prestigious journals is associated with partial or total industry funding, and this association is not explained by study quality or size.

Research paper thumbnail of Methodological issues arising from systematic reviews of the evidence of safety of vaccines

Vaccine, 2004

Adaptations to the recognized methods of systematic reviewing are required when addressing questi... more 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.

Research paper thumbnail of The effectiveness and safety of hepatitis A vaccine: a systematic review

Vaccine, 2003

We report on the conduct of a systematic review to assess the efficacy and the safety of hepatiti... more We report on the conduct of a systematic review to assess the efficacy and the safety of hepatitis A vaccines in adults and children. We identified, retrieved, and assessed all trials evaluating the effects of hepatitis A vaccines on prevention of cases of hepatitis A, death from hepatitis A, and assessing nature and frequency of adverse events. We included eight randomised trials, four containing efficacy outcomes, three containing only safety outcomes and a single study containing efficacy and adverse events outcomes. Combined inactivated vaccine effectiveness was 86% (95% CI: 63-95%). Combined attenuated vaccine effectiveness was 95% (95% CI: 81-99%). Inactivated vaccine effectiveness in the prevention of HAV secondary cases, compared to non-intervention was 82% (95% CI: 23-96%). Safety profile of vaccines was similar to that of their comparators. Despite poor design and reporting of trials, we found convincing evidence of the effectiveness and safety of inactivated HAV vaccines.

Research paper thumbnail of The use of hepatitis a vaccination in Italy: an economic evaluation

Vaccine, 2003

We report on the conduct and results of an economic model of two different strategies of vaccinat... more We report on the conduct and results of an economic model of two different strategies of vaccination against hepatitis A in Italy. In strategy 1 (universal vaccination), all newborns are vaccinated simultaneously with MMR at 15 months and all 12 year olds are vaccinated with combined hepatitis A and B vaccine. In strategy 2 (contacts' vaccination) only subjects with a close social and spatial relationship with the sick are vaccinated.

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

European Journal of Epidemiology, 2000

In Italy, the current communicable disease notification system is organised as follows: in each r... more 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 hard-copy. 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.

Research paper thumbnail of Incidence of vaccine preventable pneumococcal invasive infections and blood culture practices in Italy

Research paper thumbnail of Economic aspects of a small epidemic of hepatitis A in a religious community in Northern Italy

Journal of Infection, 1996

We report on a small (11 cases) outbreak of hepatitis A (HA) which occurred in the village of Nar... more We report on a small (11 cases) outbreak of hepatitis A (HA) which occurred in the village of Narzole in the province of Cuneo, Northern Italy. Cases were reported during the period December 1993-March 1994 and centred around a Christian community centre caring for broken homes. Eight cases were children aged 7-13 and three were adults. The incidence for all ages was 354.8 per 100 000 inhabitants. Due to local resistance to the investigation of the outbreak we were unable to identify the source of the outbreak.

Research paper thumbnail of The effectiveness and safety of vaccines against human anthrax: a systematic review

Vaccine, 1998

We report on the results of a systematic review of existing controlled clinical trials undertaken... more We report on the results of a systematic review of existing controlled clinical trials undertaken to assess the effectiveness and safety of vaccines against human anthrax in relation to disease incidence and side-effects. Two articles retrieved by electronic and hand search fulfilling some of the inclusion criteria underwent a quality assessment by a group of reviewers. Data synthesized from the two trials showed that estimates of overall effectiveness and safety favour treatment (overall odds ratio 0.16; 95% confidence interval 0.07-0.34). The route of inoculation appears to make little difference to the effectiveness of the vaccines; however, one study shows that the incidence and severity of side-effects are significantly higher with the killed vaccine than with the alum-based placebo (overall odds ratio 0.16; 95% confidence interval 2. 38-27.17).

Research paper thumbnail of Prevention and early treatment of influenza in healthy adults

Vaccine, 2000

We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a ... more We present three systematic reviews carried out within the Cochrane Collaboration, focusing on a dierent in¯uenza 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 eects of these interventions in prophylaxis and early treatments of in¯uenza and the frequency of adverse events. Additionally we present the results of the economic evaluation of eective alternatives in order to de®ne the most cost-eective intervention. The economic evaluation is set in the context of the British Army.

Research paper thumbnail of Is vaccination against hepatitis b efficient? A review of world literature

Health Economics, 1994

We report on the result of a study aimed at assessing the variability of assumptions upon which e... more We report on the result of a study aimed at assessing the variability of assumptions upon which economic models for the introduction of vaccination against Hepatitis B are based, the conclusions reached and define a minimum set of methodological standards upon which future economic studies on vaccines should be based. We identified 116 published and unpublished works by Medline literature searches, consulting private databases and corresponding with all authors and researchers active in economic evaluation of vaccines.All works were assessed but we included in our review only those which were original economic analyses (90 studies). Principal epidemiological and economic variables were extracted and compared where possible. Rough manipulations were carried out to make the data comparable. We found profound variability on the main parameters of the efficiency equation (disease incidence, costing methods, use of marginal theory, discounting and study timespan, sensitivity analysis and reporting methods). We also found inconsistencies in definition and study design in 38% of a subset of studies. Although we found scarce decision-making impact, we believe that due to uncertain or unclear methodology, few studies reach valid conclusions. In future decisions may be based on biased evidence and scarce resources committed to untested programmes. There is an urgent need to standardise study methods and define a common set of procedures.

Research paper thumbnail of Hepatitis B vaccination and multiple sclerosis: evidence from a systematic review

Journal of Viral Hepatitis, 2003

An association between administration of hepatitis B vaccine (HBV) and onset or relapse of multip... more An association between administration of hepatitis B vaccine (HBV) and onset or relapse of multiple sclerosis (MS) and other demyelinating diseases (DD) surfaced in the mid-1990s and led to an increase of studies investigating the association. Evidence from these studies, gathered within a systematic review of evidence of safety of HBV is presented. Nine published and two unpublished comparative studies identified in the Cochrane Library, MEDLINE, Embase, Current Contents, Gateway Mesh, Cinhail, Biological Abstracts and Science Citation Index and correspondence with manufacturers and researchers have been included [1][2][3][4][5][6][7][8][9][10][11]. Search strategies combined Mesh and free-text terms for study design, vaccine and DD for the period 1979-2001. Studies of noncomparative design or those not testing the association have been excluded.

Research paper thumbnail of Assessment of the efficacy and effectiveness of influenza vaccines in healthy children: systematic review

Lancet, 2005

Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inact... more Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inactivated influenza vaccines in children up to 16 years of age.

Research paper thumbnail of No evidence that vaccines cause insulin dependent diabetes mellitus

Journal of Epidemiology and Community Health, 1998

Histological and serological findings in insulin dependent diabetes mellitus (IDDM) are consisten... more Histological and serological findings in insulin dependent diabetes mellitus (IDDM) are consistent with autoimmune causes and recent work suggests polygenic inheritance. The incidence in developed countries seems to be increasing, 1 although it is unclear whether this finding is real or artefactual. Given the age of the victims of IDDM and marked diVerences in incidence of the disease in children under 15 1 (see table 1), international attention has began focusing on the nature of possible external stimuli in the genesis of IDDM. Among these, vaccination schedules have been also called into question as possible modulating factors. Classen and Classen have postulated a protective eVect of exposure to immunogens if babies are vaccinated within 42 days from birth. 2 It is known that genetic manipulation in animal models followed by early challenge with vaccine antigen can precipitate onset of Table 1 Incidence of insulin dependent diabetes mellitus in children under 15 years of age from registers of selected worldwide countries. Incidence estimates are derived from national or subnational registers. After Karvonen et al 1 Region Country Study period Incidence rates per 100 000

Research paper thumbnail of Evidence-based vaccinology: the work of the Cochrane Vaccines Field

Journal of Epidemiology and Community Health, 1998

Research paper thumbnail of An exercise on the feasibility of carrying out secondary economic analyses

Health Economics, 1996

Purchasers of health services need up to date information on cost-effectiveness of interventions ... more Purchasers of health services need up to date information on cost-effectiveness of interventions to help in prioritising spending. But economists have not yet developed a formal methodology for reviewing and summing up evidence from individual economic evaluations which may have been conducted at different times and in different places, or indeed for assessing whether such systematic reviews are possible in this context. This paper discusses the problems of reviewing available economic information, using a body of literature on the economics of influenza vaccination to illustrate some relevant issues. First, the paper examines alternative methods for adjusting prices to take into account differences in currency and time periods: Retail Price Indices are compared with health specific inflation indices, and exchange rates are compared with Purchasing Power Parity (PPP) data. For the studies reviewed, the choice of conversion method made little practical difference. Secondly, the paper explores the possibility of summarising the results of a review in terms of quantities of resources used, rather than prices. This method is constrained by the available data, but could be more generally useful as it allows direct comparison of underlying technologies, and calculation of costs by attaching local unit costs to the resources associated with an intervention. These two exercises highlight many of the problems that arise in generalising from economic studies. Both methods need to be developed further if they are to be useful to decision makers.

Research paper thumbnail of Assessment of the efficacy and effectiveness of influenza vaccines in healthy children: systematic review

Lancet, 2005

Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inact... more Background We aimed to assess evidence of efficacy and effectiveness of live attenuated and inactivated influenza vaccines in children up to 16 years of age.

Research paper thumbnail of Efficacy and effectiveness of influenza vaccines in elderly people: a systematic review

Lancet, 2005

Background Influenza vaccination of elderly individuals is recommended worldwide. Our aim was to ... more 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.

Research paper thumbnail of Antivirals for influenza in healthy adults: systematic review

Lancet, 2006

Background Use of antivirals is recommended for the control of seasonal and pandemic influenza. O... more 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.

Research paper thumbnail of Unintended events following immunization with MMR: a systematic review

Vaccine, 2003

Public debate over the safety of the trivalent measles, mumps and rubella (MMR) vaccine and the d... more Public debate over the safety of the trivalent measles, mumps and rubella (MMR) vaccine and the drop in vaccination rates in several countries persists despite its almost universal use and accepted effectiveness. We carried out a systematic review to assess the evidence of unintended effects (beneficial or harmful) associated with MMR and the applicability of systematic reviewing methods to the field of safety evaluation. Eligible studies were comparative prospective or retrospective on healthy individuals up to 15 years of age, carried out or published by 2003.

Research paper thumbnail of Relation between experimental and non-experimental study designs. HB vaccines: a case study

Journal of Epidemiology and Community Health, 1999

Study objective-To examine the relation between experimental and nonexperimental study design in ... more Study objective-To examine the relation between experimental and nonexperimental 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 eVects, and number of infections prevented by vaccination.

Research paper thumbnail of Relation of study quality, concordance, take home message, funding, and impact in studies of influenza vaccines: systematic review

British Medical Journal, 2009

To explore the relation between study concordance, take home message, funding, and dissemination ... more To explore the relation between study concordance, take home message, funding, and dissemination of comparative studies assessing the effects of influenza vaccines. Systematic review without meta-analysis. Search of the Cochrane Library, PubMed, Embase, and the web, without language restriction, for any studies comparing the effects of influenza vaccines against placebo or no intervention. Abstraction and assessment of quality of methods were carried out. We identified 259 primary studies (274 datasets). Higher quality studies were significantly more likely to show concordance between data presented and conclusions (odds ratio 16.35, 95% confidence interval 4.24 to 63.04) and less likely to favour effectiveness of vaccines (0.04, 0.02 to 0.09). Government funded studies were less likely to have conclusions favouring the vaccines (0.45, 0.26 to 0.90). A higher mean journal impact factor was associated with complete or partial industry funding compared with government or private funding and no funding (differences between means 5.04). Study size was not associated with concordance, content of take home message, funding, and study quality. Higher citation index factor was associated with partial or complete industry funding. This was sensitive to the exclusion from the analysis of studies with undeclared funding. Publication in prestigious journals is associated with partial or total industry funding, and this association is not explained by study quality or size.

Research paper thumbnail of Methodological issues arising from systematic reviews of the evidence of safety of vaccines

Vaccine, 2004

Adaptations to the recognized methods of systematic reviewing are required when addressing questi... more 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.