db‐McClure 2019.

Study characteristics
Methods	Person‐time cohort (named "risk interval analysis")
Participants	Children were eligible if they had received their first dose of measles‐containing vaccine at age 12 through 23 months from January 2003 through September 2015. Children were excluded if they had a history of seizure or conditions strongly related to seizure prior to 12 months of age. Children born before 37 weeks gestational age were classified as preterm, and children born 37 weeks gestational age as full term. Preterm children were further classified into those born < 35 weeks (early preterm) and 35 through 36 weeks (late preterm) gestational age. The authors conducted a risk‐interval analysis amongst vaccinated children, with each child having 42 days of follow‐up following receipt of a measles‐containing vaccine. Days 7 through 10 following vaccination were defined as the risk interval, and days 15 through 42 following vaccination were defined as the control interval. Days 0 through 6 and 11 through 14 following vaccination were excluded. The first exclusion reduced possible short‐term effects with concomitant vaccines, and the latter exclusion was to avoid residual exposure effects in the control interval.
Interventions	MMRV vaccination
Outcomes	Seizures were identified by diagnostic codes in the inpatient or emergency department settings.
Funding Source	Government
Notes	Conclusion: vaccination with a measles‐containing vaccine in the second year of life is associated with a similar relative risk of a first seizure in children born preterm as in those who were born full term.
Risk of bias
Bias	Authors' judgement	Support for judgement
SCCS/PTC ‐ case selection	Low risk	Adequate ‐ independent validation
SCCS/PTC ‐ exposure	Low risk	Adequate ‐ secure record
SCCS/PTC ‐ observation and exposure risk period	Low risk	Adequate ‐ observation periods are well‐defined, exposure period appears to be well‐documented
SCCS/PTC ‐ comparability	Low risk	Adjusted by age, gestational age
Summary Risk of Bias assessment	Low risk	Plausible bias is unlikely to have seriously altered the results.