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Active surveillance of adverse events following immunization (AEFI): a prospective 3-year vaccine safety study
Juny Sebastian1, Parthasarathi Gurumurthy2, Mandyam Dhati Ravi3
1Department of Pharmacy Practice, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysuru, Karnataka, India.
Insights
This study found a 13.7% incidence of adverse events following immunization (AEFIs) in Indian children, with fever being the most common. Vaccine safety surveillance is crucial for monitoring potential risks.
Area of Science:
- Pediatric vaccine safety
- Immunization surveillance
- Public health research
Background:
- Vaccine safety is paramount, alongside efficacy, in national immunization programs.
- Understanding adverse events following immunization (AEFIs) is critical for public trust and program success.
- This study focused on AEFIs in a pediatric population in India.
Purpose of the Study:
- To detect and analyze adverse events following immunization (AEFIs) in children aged 0-5 years.
- To assess the incidence and types of AEFIs associated with vaccines in a specific Indian cohort.
- To evaluate the causality of reported AEFIs using a standardized WHO algorithm.
Main Methods:
- Prospective active vaccine safety surveillance of children aged 0-5 years.
- In-person monitoring for 30 minutes post-vaccination and follow-up telephonic surveys at 8 days.
- Causality assessment of AEFIs using the World Health Organization's safety and vigilance algorithm.
Main Results:
- The overall incidence of AEFIs was 13.7%.
- Fever was the most frequent AEFI (93.2%), followed by persistent crying and diarrhea.
- Pentavac® and BCG were the vaccines most frequently implicated in AEFIs, with 93.4% showing a consistent causal association.
Conclusions:
- A higher incidence of AEFIs was observed compared to previous studies.
- AEFI surveillance is vital for detecting changes in adverse event frequency.
- Findings may indicate potential vaccine quality issues or specific local risks within the population.
Background:
Vaccines used in national immunization programs are considered safe and effective but immunization safety has become as important as the efficacy of vaccination programs. The objective of the study was to detect adverse events following immunization (AEFIs) to all vaccines administered to a pediatric population in India.
Methods:
The prospective active vaccine safety surveillance study enrolled eligible children in the age group 0-5 years receiving vaccination from the immunization center at JSS Hospital, Mysuru. Study participants were monitored at the site for 30 min following vaccination and a telephonic survey was made after 8 days to identify all AEFIs. Causality assessment of the AEFIs were done using a new algorithm developed by the safety and vigilance department of the World Health Organization.
Results:
The incidence of reported AEFIs was 13.7%. The most frequently reported AEFI was fever (n = 3095, 93.2%) with an incidence of 109.7 per 1000 doses of vaccine administered, followed by persistent crying (n = 69, 2.4 per 1000 doses of vaccine) and diarrhea (n = 57, 2.0 per 1000 doses of vaccine). The majorly implicated vaccine for AEFIs was Pentavac® followed by BCG. Consistent causal association to immunization was observed in 93.4% of cases.
Conclusions:
A high incidence rate of AEFI was observed in our study population when compared with previous published studies. AEFI surveillance studies help to detect changes in the frequency of adverse events, which may be an alert to consider vaccine quality or identify a specific risk among the local population.