DO INTERVENTIONS THAT IMPROVE IMMUNIZATION UPTAKE ALSO REDUCE SOCIAL INEQUALITIES IN UPTAKE

Objective-To investigate whether an intervention designed to improve o verall immunisation uptake affected social inequalities in uptake. Des ign-Cross-sectional small area analyses measuring immunisation uptake in cohorts of children before and after intervention. Small areas clas sified into five groups, from most deprived to most affluent, with Tow nsend deprivation score of census enumeration districts. Setting-Count y of Northumberland. Subjects-All children born in county in four birt h cohorts (1981-2, 1985-6, 1987-8, and 1990-1) and still resident at t ime of analysis. Main outcome measures-Overall uptake in each cohort o f pertussis, diphtheria, and measles immunisation, difference in uptak e between most deprived and most affluent areas, and odds ratio of upt ake between deprived and affluent areas. Results-Coverage for pertussi s immunisation rose from 53.4% in first cohort to 91.1% in final cohor t. Coverage in the most deprived areas was lower than in the most affl uent areas by 4.7%, 8.7%, 10.2%, and 7.0% respectively in successive c ohorts, corresponding to an increase in odds ratio of uptake between d eprived and affluent areas from 1.2 to 1.6 to 1.9 to 2.3. Coverage for diphtheria immunisation rose from 70.0% to 93.8%; differences between deprived and affluent areas changed from 8.6% to 8.3% to 9.0% to 5.5% , corresponding to odds ratios of 1.5, 2.0, 2.5, and 2.6. Coverage for measles immunisation rose from 52.5% to 91.4%; differences between de prived and affluent areas changed from 9.1% to 5.7% to 8.2% to 3.6%, c orresponding to odds ratios of 1.4, 1.4, 1.7, and 1.5. Conclusion-Desp ite substantial increase in immunisation uptake, inequalities between deprived and affluent areas persisted or became wider. Any reduction i n inequality occurred only after uptake in affluent areas approached 9 5%. Interventions that improve overall uptake of preventive measures a re unlikely to reduce social inequalities in uptake.