Search PubMed⌕ Search

Biomedical subjects

Tom Jefferson

Publications and source records attributed to Tom Jefferson.

At least 19 recordsLinked to original sources
PubMed2004

Adverse events after immunisation with aluminium-containing DTP vaccines: systematic review of the evidence.

We have reviewed evidence of adverse events after exposure to aluminium-containing vaccines against diphtheria, tetanus, and pertussis (DTP), alone or in combination, compared with identical vaccines, either without aluminium or containing aluminium in different concentrations. The study is a systematic review with meta-analysis. We searched the Cochrane Vaccines Field Register, the Cochrane Library, Medline, Embase, Biological Abstracts, Science Citation Index, and the Vaccine Adverse Event Reporting System website for relevant studies. Reference lists of retrieved articles were scanned for further studies. We included randomised and semi-randomised trials and comparative cohort studies if the report gave sufficient information for us to extract aluminium concentration, vaccine composition, and safety outcomes. Two reviewers extracted data in a standard way from all included studies and assessed the methodological quality of the studies. We identified 35 reports of studies and included three randomised trials, four semi-randomised trials, and one cohort study. We did a meta-analysis of data from five studies around two main comparisons (vaccines containing aluminium hydroxide vs no adjuvant in children aged up to 18 months and vaccines containing different types of aluminium vs no adjuvants in children aged 10-16 years). In young children, vaccines with aluminium hydroxide caused significantly more erythema and induration than plain vaccines (odds ratio 1.87 [95% CI 1.57-2.24]) and significantly fewer reactions of all types (0.21 [0.15-0.28]). The frequencies of local reactions of all types, collapse or convulsions, and persistent crying or screaming did not differ between the two cohorts of the trials. In older children, there was no association between exposure to aluminium-containing vaccines and onset of (local) induration, swelling, or a raised temperature, but there was an association with local pain lasting up to 14 days (2.05 [1.25-3.38]). We found no evidence that aluminium salts in vaccines cause any serious or long-lasting adverse events. Despite a lack of good-quality evidence we do not recommend that any further research on this topic is undertaken.

Adjuvants, Immunologic↗
PubMed2003

Get peered!

Explore the source record for details and available documents.

Play and Playthings↗
PubMed2003

Unintended events following immunization with MMR: a systematic review.

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. We identified 120 articles satisfying our inclusion criteria and included 22. MMR is associated with a lower incidence of upper respiratory tract infections, a higher incidence of irritability, similar incidence of other adverse effects compared to placebo and is likely to be associated with benign thrombocytopenic purpura (TP), parotitis, joint and limb complaints and aseptic meningitis (mumps Urabe strain-containing MMR). Exposure to MMR is unlikely to be associated with Crohn's disease, ulcerative colitis, autism or aseptic meningitis (mumps Jeryl-Lynn strain-containing MMR). 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 immunization with MMR cannot be separated from its role in preventing the target diseases.

Bias↗
PubMed2003

Systematic review of the effects of pertussis vaccines in children.

OBJECTIVE: To assess the efficacy and safety of whole-cell and acellular pertussis vaccines administered to children singly or within diphtheria, tetanus and pertussis (DTP) vaccines. DATA SOURCES: We searched the Cochrane Library, MEDLINE, EMBASE, Biological Abstracts and Science Citation Index to December 2001. Specialised websites and bibliographies of retrieved articles and reviews were assessed. Vaccine manufacturers and investigators were contacted for additional data. REVIEW METHODS: We included randomised and cohort studies comparing efficacy and/or safety of pertussis vaccines with placebo, DT, no intervention or each other. RESULTS: We included 52 studies (49 randomised controlled trials (RCTs), 3 cohort studies). All tested whole-cell and acellular vaccines were significantly more effective than placebo against pertussis. Absolute efficacy of whole-cell DTP varied from 37 to 92%. One- and two-component acellular vaccines had lower absolute efficacy (67-70%), than vaccines with >/=3 components (80-84%). Whole-cell vaccines were associated with significantly higher incidences of swelling and induration (odds ratio (OR) 11.67, 95% confidence interval (CI) 8.83-15.44), fever (OR for fever >39 degrees C 3.36, 95% CI 2.06-5.49) and crying for >2h (OR 4.72, 95% CI 2.94-7.59) than placebo or DT. Differences in incidence of hypotonic hyporesponsive episodes (HHE) and convulsions were not statistically significant. Acellular pertussis vaccines did not cause a higher incidence of local signs, fever, convulsions, HHE or prolonged crying than placebo or DT. CONCLUSION: All tested pertussis vaccines were efficacious. Whole-cell vaccines show variable efficacy, making interpretation of direct comparisons unreliable. Acellular vaccines with >/=3 antigenic components showed higher efficacy than one- and two-component vaccines. The adverse event profile of acellular vaccines was similar to that of placebo and considerably better than that of whole-cell vaccines.

Child↗
PubMed2002

The Brighton Collaboration: addressing the need for standardized case definitions of adverse events following immunization (AEFI).

UNLABELLED: To further scientific progress of immunization safety, comparability of data from clinical trials and surveillance systems is essential. Comparability requires the availability of standardized case definitions for adverse events following immunization (AEFI) and guidelines for case determination, recording and data presentation. METHOD: International collaborative working groups, consisting of professional volunteers from developed and developing countries, conduct systematic literature reviews to develop 50-100 AEFI definitions. Case definitions are finalized after a comment period by a reference group consisting of organizations concerned with immunization safety, and will be disseminated via the world-wide-web and other means for free world-wide use. RESULTS: Literature reviews yielded substantial diversity in data collection and presentation. We have developed standardized case definitions together with guidelines for use in clinical trials and surveillance systems. CONCLUSIONS: Diversity in safety methods leads to considerable loss of scientific information. We have built the necessary international network of currently about 300 participants from patient care, public health, scientific, pharmaceutical, regulatory and professional organizations to develop and assess standardized AEFI case definitions and guidelines. Evaluation studies, global implementation, ongoing definition development and a continuously growing network will be essential for the success of the collaboration.

Adverse Drug Reaction Reporting Systems↗