| Study characteristics |
| Methods |
Retrospective cohort study ‐ USA ‐ data from Vaccine Safety Datalink: Group Health Cooperative (Washington state), Kaiser Permanente Colorado, Kaiser Permanente Northwest (Oregon), Harvard Pilgrim Health Care (Massachusetts), HealthPartners (Minnesota), Northern California Kaiser Permanente, and Marshfield Clinic (Wisconsin). Linked to cb‐Klein 2012; cb‐Klein 2010
|
| Participants |
N = 946,806 children who were < 36 months of age who received a first dose of any measles‐containing vaccine from 2000 to 2012 |
| Interventions |
MMRV (Merck & Co)
MMR (Merck & Co Inc, West Point, PA) + V (Merck & Co) |
| Outcomes |
Postvaccination seizure event as the first instance during the 42 days after a measles‐ or varicella‐containing vaccine of ICD‐9 codes 345* (epilepsy) or 780.3* (convulsion) in the emergency department or hospital |
| Funding Source |
Government |
| Notes |
Discussion: children who received MMRV vaccine or who had prior medically attended fevers and seizures during the first year of life had increased risk of fever after a first dose of measles vaccine. After adjusting for familial propensity to seek care, MCV‐associated fever still clustered within families, suggesting a possible genetic basis for susceptibility to developing fever due to measles vaccines. |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| PCS/RCS ‐ exposed cohort selection |
Low risk |
Adequate ‐ registry Kaiser Permanente ‐ representative of exposed |
| PCS/RCS ‐ non‐exposed cohort selection |
Low risk |
Adequate ‐ drawn from the same community |
| PCS/RCS ‐ comparability |
Low risk |
Adequate ‐ adjusted for age group Vaccine Safety Datalink sites respiratory virus season |
| PCS/RCS ‐ assessment of outcome |
Low risk |
Adequate ‐ hospital record with blind assessment |
| Summary Risk of Bias assessment |
Low risk |
Plausible bias is unlikely to have seriously altered the results. |
