Analysis of the causality assessment outcomes for adverse events following immunisation caused by vaccines administered as part of the expanded program on immunisation
1
Medicines Information Centre, Division of Clinical Pharmacology, University of Cape Town, Cape Town, South Africa
2
Communicable Disease Control, Western Cape Department of Health and Wellness, Service Priorities Coordination, Cape Town, South Africa
Popul. Med. 2026;8(Supplement Supplement 1):A3951
ABSTRACT
BACKGROUND:
Vaccines are central to eradicating poliomyelitis, measles, and neonatal tetanus, and remain the most cost-effective strategy to reduce vaccine-preventable diseases (VPD).¹ However, concerns about vaccine safety and misinformation from seemingly credible sources undermine these efforts.² Monitoring vaccine safety and investigating adverse events following immunisation (AEFI) are crucial to addressing these concerns and alleviating public fears.²
METHODS:
We conducted a descriptive epidemiological analysis combined with statistical methods. AEFI cases were reported by healthcare workers at the facility level or by patients. This study focused on reports of AEFI in the Expanded Programme on Immunisation (EPI) in patients up to 12 years of age. Each case underwent a detailed investigation, with clinical data collected according to established case definitions. The findings were submitted to the National Immunisation Safety Expert Committee (NISEC) for causality assessment.
RESULTS:
From January 2021 to December 2024, 100 cases were reported. Of these, 61 were classified as serious. Most cases stemmed from the cape metro (78%). Causality assessment outcomes were available for 43 cases. Of these, 10 cases (23%) were coincidental, 20 (47%) were consistent with vaccination, 7 (16%) were inconsistent with causal association, 1 (2%) was indeterminate, and 5 (12%) were unclassifiable. Among the 20 consistent cases, 1 was stress-related, 4 resulted from vaccination errors, 6 were known reactions to the Bacillus Calmette-Guérin (BCG) vaccine, and 9 were known vaccine product-related reactions to other EPI vaccines.
CONCLUSIONS:
The number of injuries caused by vaccination errors underscores the need for mandatory refresher training and creating awareness of the need to report AEFI. Addressing these issues through robust vaccine safety monitoring and communication strategies is essential to restoring public confidence and improving immunisation uptake. Moving from paper-based to electronic reporting, for ease of use, could also encourage reporting.
Vaccines are central to eradicating poliomyelitis, measles, and neonatal tetanus, and remain the most cost-effective strategy to reduce vaccine-preventable diseases (VPD).¹ However, concerns about vaccine safety and misinformation from seemingly credible sources undermine these efforts.² Monitoring vaccine safety and investigating adverse events following immunisation (AEFI) are crucial to addressing these concerns and alleviating public fears.²
METHODS:
We conducted a descriptive epidemiological analysis combined with statistical methods. AEFI cases were reported by healthcare workers at the facility level or by patients. This study focused on reports of AEFI in the Expanded Programme on Immunisation (EPI) in patients up to 12 years of age. Each case underwent a detailed investigation, with clinical data collected according to established case definitions. The findings were submitted to the National Immunisation Safety Expert Committee (NISEC) for causality assessment.
RESULTS:
From January 2021 to December 2024, 100 cases were reported. Of these, 61 were classified as serious. Most cases stemmed from the cape metro (78%). Causality assessment outcomes were available for 43 cases. Of these, 10 cases (23%) were coincidental, 20 (47%) were consistent with vaccination, 7 (16%) were inconsistent with causal association, 1 (2%) was indeterminate, and 5 (12%) were unclassifiable. Among the 20 consistent cases, 1 was stress-related, 4 resulted from vaccination errors, 6 were known reactions to the Bacillus Calmette-Guérin (BCG) vaccine, and 9 were known vaccine product-related reactions to other EPI vaccines.
CONCLUSIONS:
The number of injuries caused by vaccination errors underscores the need for mandatory refresher training and creating awareness of the need to report AEFI. Addressing these issues through robust vaccine safety monitoring and communication strategies is essential to restoring public confidence and improving immunisation uptake. Moving from paper-based to electronic reporting, for ease of use, could also encourage reporting.
| eISSN: | 2654-1459 |
We process personal data collected when visiting the website. The function of obtaining information about users and their behavior is carried out by voluntarily entered information in forms and saving cookies in end devices. Data, including cookies, are used to provide services, improve the user experience and to analyze the traffic in accordance with the Privacy policy. Data are also collected and processed by Google Analytics tool (more).
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.
