individual reports of adverse events following immunizations (AEFI) can
be challenging. Most published reviews are based on expert opinions, but
the methods and logic used to arrive at these opinions are neither well
described nor understood by many health care providers and scientists.
The Clinical Immunization Safety Assessment (CISA) network developed a
standardized algorithm to help health care providers assess the causal
relationship between individual adverse events and vaccines.
We hope that this algorithm approach can assist with educational efforts
to improve the collection of key information on AEFI and provide a
platform for teaching about causality assessment.
- Publication: Halsey NA, Edwards KM, Dekker CL, Klein NP, Baxter
R, Larussa P, Marchant C, Slade B, Vellozzi C; Causality
Working Group of the Clinical Immunization Safety
Assessment network. Algorithm to assess
causality after individual adverse events following
immunizations. Vaccine 2012 Aug
PubMed abstract |
article (may require password)
Algorithm: link to the algorithm
from the above publication.
Causality Tool - This tool is intended as a teaching tool and is not designed to to replace a physician's independent judgement regarding patient care.
- Sample Cases: Illustrations of how
various adverse events progress through the online
20 year-old female developed hives 1 hour after
influenza vaccine (no other exposures)
- Febrile Seizures
- Case 1:
12 month-old with AEFI 9 days after MMR
- Case 2:
12 month-old with AEFI 4 days after MMR
- ADEM (Acute Disseminated Encephalomyelitis):
13 year-old male developed acute neurologic disorder
12 days after meningococcal vaccine; diagnosed as
ADEM following MRI (no other exposures)
CISA - Clinical Immunization Safety Assessment
Project - a national network of vaccine
safety experts from the CDCís Immunization Safety Office
(ISO), seven medical research centers, and other
partners, which provides a comprehensive vaccine safety
public health service to the nation.
was last updated on
October 18, 2017
Institute for Vaccine Safety