Objective: To compare the characteristics of clinical cases of measles with confirmed cases of measles registered in Cataluña during a period of four months.
Patients and methods: An epidemiological survey was carried out on 171 cases of measles detected by a specific system of surveillance. The survey included data on age, sex, clinical symptoms, laboratory confirmation, immunization status and probable site of transmission. The relationship between the variable case (with or without laboratory confirmation) and the rest of variables was determined by the adjusted odds ratio, using a model of logistic regression.
Results: The epidemiological survey showed that 30.4% (52/171) had laboratory confirmation, 12.9% (22/171) had epidemiological confirmation and the rest, 56.7% (97/171) only complied with the clinical definition. The rash had a longer duration in confirmed cases (5.9 days) than in non confirmed cases (5.2 days). The lack of laboratory confirmation was associated with age younger than 5 years (ORa = 0.1; 95% CI 0.1-0.8), but there were no differences in sex, immunization status or others clinical symptoms.
Conclusion: In clinical cases of measles the duration of the rash was lower than confirmed cases. The proportion of cases with laboratory confirmation was low (30.4%) and should be increased in the future. History of previous immunization ought not to rule out diagnosis of measles.