Lack of association between intussusception and oral polio vaccine in Cuban children.

Two exploratory investigations found an increased risk of intussusception after oral polio vaccine (OPV). A large, national, population-based study was undertaken in Cuba to investigate a possible association. Three hundred and thirty-five cases of intussusception in children under 2 years of age occurring in 1995-2000 were identified and their OPV records retrieved. The relative incidence (RI) of intussusception in defined periods up to 42 days after OPV in children under 1 year was estimated using the self-controlled case series method, controlling for age and season. The RI was not significantly raised in any of the time intervals examined within the 0-42 day period after OPV. For the period 0-42 days as a whole the RI was 1.11, 95% CI 0.74-1.67. This study does not support the hypothesis that OPV causes intussusception.

Outbreak of aseptic meningitis associated with mass vaccination with a urabe-containing measles-mumps-rubella vaccine: implications for immunization programs.

A mass immunization campaign with a Urabe-containing measles-mumps-rubella vaccine was carried out in 1997 in the city of Salvador, northeastern Brazil, with a target population of children aged 1-11 years. There was an outbreak of aseptic meningitis following the mass campaign. Cases of aseptic meningitis were ascertained through data collected from the records of children admitted to the local referral hospital for infectious diseases between March and October of 1997, using previously defined eligibility criteria. Vaccination histories were obtained through home visits or telephone calls. Eighty-seven cases fulfilled the study criteria. Of those, 58 cases were diagnosed after the vaccination campaign. An elevated risk of aseptic meningitis was observed 3 weeks after Brazil's national vaccination day compared with the risk in the prevaccination period (relative risk = 14.3; 95% confidence interval: 7.9, 25.7). This result was confirmed by a case series analysis (relative risk = 30.4; 95% confidence interval: 11.5, 80.8). The estimated risk of aseptic meningitis was 1 in 14,000 doses. This study confirms a link between measles-mumps-rubella vaccination and aseptic meningitis. The authors discuss the implications of this for the organization and planning of mass immunization campaigns.