evidence: Serious adverse events are rare following immunization and, in most cases, data are insufficient to determine a causal association. [...] Anaphylaxis following immunization with PCECV has been rarely reported. Temporally associated neurologic events have also been very rarely reported but causal association with vaccination has not been established. [...] Vaccine providers are asked to report, through local public health officials, any serious or unexpected adverse event felt to be temporally related to vaccination. An unexpected AEFI is an event that is not listed in available product information but may be due to the immunization, or a change in the frequency of a known AEFI. Refer to Reporting Adverse Events Following Immunization (AEFI) in Canada for additional information about AEFI reporting.