Trends in hospital admission rates for whooping cough in England across five decades: database studies

Objectives: Our aim was to report on trends in hospitalisation rates for pertussis in England from the 1960s to 2011; and to provide context for the recent unexpected activity of Bordetella pertussis in the UK. Design: A retrospective analysis of English national Hospital Episode Statistics (HES, 1968-2011) and the Oxford Record Linkage Study (ORLS, 1963-2011) for people admitted to hospital with whooping cough. Setting: England and the Oxford Record Linkage Study area. Main outcome measures: Age-and gender-specific hospital admission rates, and summary age-and sex-standardised rates, for people aged under 25 years per 100,000 population in each age group. Results: Admission rates declined from the 1960s to the early 1970s. For example, the standardised rates were 12.8 (95% confidence interval 11.2-14.5) per 100,000 in England in 1968 and 4.0 (3.0-4.9) per 100,000 in 1973. They then increased to reach 45.0 (41.4-48.6) per 100,000 in 1978 and 47.4 (43.7-51.1) in 1982. From the late 1980s, admission rates continued to decline, falling to between 1 and 4 per 100,000 in each of the years between 2003 and 2011. While the trend in hospital admissions closely followed that in notifications, the annual ratio between these two measures was not consistent ranging from 1.07 (95% confidence interval 1.00-1.14) to 4.03 (3.79-4.27) notifications per admission over the last 10 years. Conclusions: Epidemics of whooping cough in the late 1970s and early 1980s were associated with a significant rise in hospital admission rates. Current admission rates are low, by historical comparison. Vaccine programmes must continue to be fully implemented in order to improve control of pertussis activity.