OUTBREAK OF ASEPTIC MENINGITIS ASSOCIATED WITH MASS VACCINATION WITH A URABE CONTAINING MMR VACCINE
Informed Parent Issue 2 --2000
Taken from: American Journal of Epidemiology, Vol 151, No. 5. 2000
A mass immunisation campaign with a Urabe-containing MMR vaccine was carried out in 1997 in the city of Salvador, NE 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. 87 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 Brazils 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 (rr = 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 MMR vaccination and aseptic meningitis.
The authors discuss the implications of this for the organisation and planning of mass immunisation campaigns. AMJ Epidemiol 2000; 151: 524-30
Editor: Two brands of Urabe-containing MMR vaccines (Plucerix & Immravax) were withdrawn from the UK in 1992 because of aseptic meningitis, so WHY was it being used in this 1997 Brazilian campaign?
The above paper stated that the MMR vaccine used in Salvador was the Pluserix vaccine supplied by SmithKline Beecham Pharmaceuticals, London, UK The authors of the paper also state that this study raises new practical questions regarding public health. The issue is not simply whether or not a specific vaccine is associated with an adverse event, but the extent to which a specific vaccination strategy influences the visibility (our emphasis) of the adverse event despite its confirmed relative rarity, and hence affects public confidence.