Related Experiment Videos
Outbreak of aseptic meningitis associated with mass vaccination with a urabe-containing measles-mumps-rubella
I Dourado1, S Cunha, M G Teixeira
1Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Brazil.
Insights
A mass measles-mumps-rubella (MMR) vaccination campaign in Brazil led to an outbreak of aseptic meningitis. The study found a significant increase in meningitis risk following the campaign, estimating it at 1 in 14,000 doses.
Area of Science:
- Epidemiology
- Vaccinology
- Public Health
Background:
- A mass immunization campaign using a Urabe-containing measles-mumps-rubella (MMR) vaccine was conducted in Salvador, Brazil, in 1997.
- An outbreak of aseptic meningitis was observed following this campaign.
Purpose of the Study:
- To investigate the association between the Urabe-containing MMR vaccine campaign and aseptic meningitis.
- To quantify the risk of aseptic meningitis associated with the vaccination.
Main Methods:
- Retrospective case ascertainment from hospital records of children aged 1-11 years.
- Vaccination histories collected via home visits or telephone calls.
- Analysis of case series and comparison of risk during post-vaccination and pre-vaccination periods.
Main Results:
- Eighty-seven cases of aseptic meningitis meeting study criteria were identified.
- A significantly elevated risk of aseptic meningitis was observed 3 weeks post-vaccination (Relative Risk = 14.3).
- The estimated risk was approximately 1 case per 14,000 MMR vaccine doses.
Conclusions:
- The study confirms a causal link between Urabe-containing MMR vaccination and aseptic meningitis.
- Findings have implications for the planning and organization of mass immunization programs.
- Careful consideration of vaccine strain and potential adverse events is warranted.
Abstract:
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.