Does primary immunisation status predict MMR uptake?
- 1Centre for Paediatric Epidemiology and Biostatistics, UCL Institute of Child Health, London, UK
- 2Children’s Population Health Unit, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London, UK
- Helen Bedford, Centre for Paediatric Epidemiology and Biostatistics, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK;
- Accepted 22 April 2008
- Published Online First 7 May 2008
Objective: To investigate the relationship between primary immunisation status and MMR uptake.
Design: Nationally representative Millennium Cohort Study.
Setting: Children born in the UK, 2000–2002.
Participants: 14 578 children with immunisation data.
Main outcome measures: MMR status at 3 years, defined as immunised with MMR, immunised with at least one single antigen vaccine or unimmunised.
Results: 88.6% of children had been immunised with MMR, 5.2% had received at least one of the single antigen vaccines and 6.1% were unimmunised against measles, mumps and rubella at age 3 years. Children who were unimmunised with the primary vaccines at ages 9 months (1.2%, n = 168) and 3 years (0.4%, n = 67) were 13 (95% CI 10.8 to 14.7) and 17 (95% CI 14.6 to 19.7) times more likely to be unimmunised against measles, mumps and rubella compared with children who were fully immunised. They were also more likely to be immunised with at least one of the single antigen vaccines with risk ratios of 2.8 (95% 1.2 to 6.1) and 4.3 (95% CI 1.8 to 10.1). Similar but smaller associations were observed if children were partially immunised with the primary vaccines at 9 months (3.4%, n = 502) and 3 years (3.6%, n = 522) with risk ratios of 4.0 (95% 3.2 to 4.9) and 5.2 (95% 4.2 to 6.1) for no MMR immunisation, and 2.0 (95% C 1.1 to 3.6) and 1.6 (95% CI 1.1 to 2.5) for single antigen vaccine use.
Conclusion: Children who remain unimmunised with primary vaccines are also more likely not to receive MMR. More work is needed to determine how best to target this group.
Other members of the Millennium Cohort Study Child Health Group include Carol Dezateux, Catherine Peckham, Tim J Cole, Lucy Griffiths, Summer Sherburne Hawkins, Suzanne Bartington, Jugnoo Rahi and Phillippa Cumberland of the Centre for Paediatric Epidemiology and Biostatistics, UCL Institute of Child Health, London.
Funding: The Millennium Cohort Study is funded by grants to the director of the study from the Economic and Social Research Council and a consortium of government funders. This work received funding from the Department of Health and was undertaken at GOSH/UCL Institute of Child Health which received a proportion of funding from the Department of Health’s NIHR Biomedical Research Centres funding scheme. The study sponsors played no part in the design, data analysis and interpretation of this study, the writing of the manuscript, or the decision to submit the paper for publication and the authors’ work was independent of their funders.
Competing interests: HB and DE have been reimbursed in the past by a number of vaccine manufacturers for attending conferences, speaking and conducting research. DE has also provided expert reports for potential litigants in court cases involving vaccines. All other authors declare that they have no competing interests.
Ethics approval: Ethics approval was received from the South West and London Multi-Centre Research Ethics Committees. No further approval was required for this particular study.