Measles resurgence in Argentina: 1997-8 outbreak.

Epidemiological and clinical findings from 1162 serologically confirmed measles cases occurring in Buenos Aires, Argentina in 1997 and 1998 were retrospectively reviewed. From 90 hospitalized children, measles virus was detected by direct RT-PCR from nasopharyngeal secretions. Patients were grouped as follows: (i) not vaccinated: infants < 12 months; (ii) regularly vaccinated: children 1-4 years not covered by the last catch-up; (iii) catch-up vaccinated: patients 5-19 years immunized during the 1993 campaign. Most cases were recorded in non-vaccinated infants (54%), and the lowest in catch-up vaccinated children (16%). Mean age of the 90 hospitalized children was 11.3 months. Pneumonia was the major hospitalization cause followed by pneumonitis. Two children required intensive care and one died. The 1993 catch-up campaign seemed to reduce the number of cases in the 5- to 19-year-old group. Lack of timely follow-up probably led to the accumulation of susceptible individuals allowing measles re-emergence. Direct viral detection by RT-PCR proved to be a sensitive tool for molecular epidemiology surveillance.