TABLE 1

Characteristics of Prespecified Adverse Events

Medical SettingPostvaccination Risk Window, dFirst Episode in What Period?Primary Comparison Groupa
Uncommon or rare adverse event
 AnaphylaxisED, inpatient0–2First in 42 dHistoric
 AppendicitisED, inpatient1–42First in 42 dHistoric
 PancreatitisED, inpatient1–42First everHistoric
 GBSOutpatient, ED, inpatient1–42First in 42 dHistoric
 CIDPOutpatient, ED, inpatient1–180First everHistoric
 SeizureED, inpatient0–42First in 42 d and first everConcurrent
 StrokeED, inpatient0–42First in 42 dHistoric
 VTEOutpatient, ED, inpatient1–42First in 1 yHistoric
Common adverse event
 Allergic reactionsOutpatient, ED, inpatient0–2 for ED and inpatient,1–2 for outpatientFirst in 42 dConcurrent
 Injection site reactionsOutpatient, ED, inpatient1–6First in 42 dConcurrent
 Nonspecific reactionsOutpatient, ED, inpatient0–6First in 42 dConcurrent
 SyncopeOutpatient, ED, inpatientDay 0First in 2 dConcurrent
  • a Concurrent comparison group: visits during which comparator vaccines were administered, with analytic strata defined by age (in 1-y increments), site, sex, and week of the vaccination visit. Two historic comparison groups (2007–2014) were used: general VSD population and vaccinated VSD population, vaccinated with comparator vaccines.