Immunisation levels---need they all decline?

Immunisation levels in West Sussex for the period 1970 to 1976 were reviewed. The national decline in immunisation against whooping cough was reflected locally in 1974, 1975, and 1976 but, in contrast to the national experience, levels of immunisation against diphtheria, tetanus, poliomyelitis, or measles did not decline. It is suggested that this difference is accounted for by the use of a computer system which keeps an "immunisation diary" for parents and for medical and nursing staff.