Risks of convulsion and aseptic meningitis following measles-mumps-rubella vaccination in the United Kingdom.
Measles-mumps-rubella (MMR) vaccines containing the Urabe strain of mumps were withdrawn in the United Kingdom in 1992 following demonstration of an increased risk of aseptic meningitis 15-35 days after vaccination. Following introduction of a replacement MMR vaccine (Priorix; GlaxoSmithKline, London, United Kingdom) in 1998, active surveillance of aseptic meningitis and convulsion was established to evaluate the risk associated with the new vaccine. No laboratory-confirmed cases of mumps meningitis were detected among children aged 12-23 months after administration of 1.6 million doses of Priorix (upper 95% confidence limit of risk: 1:437,000) in England and Wales. The upper 95% confidence limit excluded the risk found for mumps meningitis with Urabe vaccines (1:143,000 doses). No cases of aseptic meningitis were detected among children aged 12-23 months, who had received over 99,000 doses of Priorix (upper 95% confidence limit of risk: 1:27,000), in a regional database of hospital-admitted cases. This compares with an observed risk of 1:12,400 for Urabe vaccines. An elevated relative incidence of convulsion was found in the 6- to 11-day period after receipt of Priorix (relative incidence = 6.26, 95% confidence interval: 3.85, 10.18)-consistent with the known effects of the measles component of MMR vaccine-but not in the 15- to 35-day period (relative incidence = 1.48, 95% confidence interval: 0.88, 2.50) as occurred with Urabe-containing vaccines. This study demonstrates the power of active postmarketing surveillance to identify or exclude events too rare to be detected in prelicensure trials.
Miller
E
E
Immunisation Department, Centre for Infections, Health Protection Agency, 61 Colindale Avenue, London, UK. liz.miller@hpa.org.uk
Andrews
N
N
Stowe
J
J
Grant
A
A
Waight
P
P
Taylor
B
B
D004739:England / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D038801:International Classification of Diseases; D022542:Measles-Mumps-Rubella Vaccine / Q000009:adverse effects* / Q000600:supply & distribution; D008498:Medical Record Linkage; D016347:Medical Records Systems, Computerized; D008582:Meningitis, Aseptic / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D009109:Mumps virus / Q000145:classification; D010343:Patient Admission / Q000706:statistics & numerical data; D011159:Population Surveillance; D011358:Product Surveillance, Postmarketing; D012307:Risk Factors; D012640:Seizures / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D014611:Vaccination / Q000009:adverse effects / Q000706:statistics & numerical data; D014852:Wales / Q000453:epidemiology
D022542:Measles-Mumps-Rubella Vaccine