pca France 2006.

Methods	Retrospective cohort study based on Vaccine Safety Datalink, assessing the effect of influenza vaccination of pregnant women in preventing respiratory illness in newborns. 6 epidemic seasons were considered.
Participants	Infants who were born before or during the influenza season at 4 MCOs (Kaiser Permanente Colorado, Denver; Kaiser Permanente Northern California, Oakland; Kaiser Permanente Northwest, Portland, Oregon; and Group Health Cooperative, Seattle, Washington) between 1 October 1995 and 30 September 2001 were eligible for study inclusion. Mother‐infant pairs were included in the final study population if: the mothers were aged 18 to 45 years and enrolled in the MCO for longer than 1 year; the infants’ gestational age was at least 30 weeks at birth; the infants were continuous MCO members for at least 14 days during the influenza season; the infants had a least 1 outpatient visit during the first 3 months of life.
Interventions	An infant was considered exposed if the mother was vaccinated against influenza during the pregnancy and there were at least 28 days from the vaccination date of the mother to the birth date of the infant. Infants of mothers vaccinated within 27 days of birth were excluded from the primary analysis.
Outcomes	Medically attended ARI
Notes	Government funded
Risk of bias
Bias	Authors' judgement	Support for judgement
PCS/RCS ‐ selection exposed cohort All outcomes	High risk	From MCO databases
PCS/RCS ‐ selection non‐exposed cohort All outcomes	High risk	From MCO databases
PCS/RCS ‐ comparability All outcomes	High risk	Poor matching
PCS/RCS ‐ assessment of outcome All outcomes	Unclear risk	Datalink
Summary assessment	High risk	High risk