Objective: To describe epidemiological, clinical, and cerebrospinal fluid (CSF) findings in cases of aseptic meningitis associated with measles-mumps-rubella vaccination following a mass immunization campaign in the Brazilian state of Bahia in August 1997 promoted by the country's Ministry of Health, and to compare these cases to the cases of aseptic meningitis not associated with the vaccine that occurred in the same year.
Methods: Between March 1997 and October 1997, all individuals between 1 and 12 years of age admitted to the Couto Maia Hospital (the Bahia reference hospital for infectious illnesses) with a clinical and laboratory diagnosis of aseptic meningitis were prospectively followed. The study population was divided into two groups: one with individuals who had received the vaccine, and one with individuals who had not received the vaccine. Demographic, clinical, and laboratory information was collected on both groups.
Results: In September, following the vaccination campaign, 74 cases of aseptic meningitis were registered at the Couto Maia Hospital, versus the monthly average of 7.5 cases. We observed a greater frequency of nuchal rigidity and increased CSF cellularity among children whose meningitis was associated with the vaccine. However, encephalitic involvement was more frequent in the group of children with non-vaccinal meningitis.
Conclusions: Although the course of post-vaccinal meningitis is more benign than that of other forms of the disease, its treatment generates costs related to ancillary exams and hospitalizations. Mass vaccination campaigns should employ less reactogenic vaccine strains.