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How were DTP-related adverse events reduced after the introduction of an acellular pertussis vaccine in Chile?
Francisca Aguirre-Boza1, Pamela San Martín P1, María Teresa Valenzuela B1
1Vicedecanato de Investigación. Facultad de Medicina, Universidad de Los Andes, Chile.
Insights
Adverse event reports for pertussis vaccines in Chilean infants decreased significantly after 2018. This trend coincided with the introduction of a new combination vaccine, indicating improved safety profiles.
Area of Science:
- Vaccinology and Immunology
- Pediatric Public Health
- Pharmacovigilance
Background:
- Pertussis-containing vaccines are crucial for infant immunization.
- Monitoring adverse events following immunization (AEFI) is essential for vaccine safety surveillance.
- Chile's National Immunization Program (NIP) utilizes both whole-cell (wP) and acellular (aP) pertussis vaccines.
Purpose of the Study:
- To analyze trends in AEFI reports for pertussis component vaccines in infants under two years old in Chile.
- To compare AEFI frequencies between whole-cell (wP) and acellular (aP) pertussis vaccines.
- To assess the impact of new vaccine introductions on AEFI reporting rates.
Main Methods:
- Retrospective observational study of AEFI records submitted to the AEFI NIP from January 1, 2015, to June 30, 2020.
- Descriptive analysis of AEFI reports, stratified by DTP vaccine type (wP or aP) and AEFI type using MedDRA terminology.
- Calculation of reporting rates per 100,000 vaccine doses administered.
Main Results:
- A total of 1,697 AEFI reports were analyzed: 815 for wP, 417 for aP, and 465 of unknown type.
- Reporting rates per 100,000 doses decreased from 40.1 in 2015 to 12.2 in 2020.
- Most common AEFIs included injection site erythema (42.9%), pyrexia (35.7%), and pain (29.2%). Serious adverse events (SAEs) accounted for 5.8% of all cases.
Conclusions:
- A significant decline in AEFI reports was observed starting in 2018.
- This decrease correlates with the introduction of the DTaP-IPV-HepB-Hib vaccine into the NIP.
- The findings suggest a potential improvement in the safety profile of the updated vaccine schedule.
Objectives:
To describe the trend in the frequency of adverse events (AE) records associated to pertussis component vaccines between January 1st, 2015 and June 30th, 2020 in infants younger than 2-years-old in Chile, by reviewing the records submitted to the AEFI NIP, stratified by DTP-vaccine type, wP or aP.
Materials And Methods:
This was a retrospective observational study including all AEFI records of DTP (either aP or wP)-containing vaccines in the described sample. A descriptive analysis was performed according to vaccine type and AEFI, using MedDRA terminology.
Results:
The total number of AEFI reports was 1,697: 815 corresponding to wP vaccines, 417 to aP vaccines, and 465 with unknown type. The reporting rates for the years 2015 to 2020 were 40.1, 56.2, 37.1, 24.7, 19.1, and 12.2 per 100,000 doses administered, respectively. The most reported AEFI were injection site erythema (42.9%), pyrexia (35.7%), and pain at the injection site (29.2%). Among all cases, 5.8% were SAEs (n = 98), 5.9% were SAEs for wP vaccines (n = 48) and 5.3% were for aP vaccines (n = 22).
Discussion:
A significant decrease in AEFI reports was observed as of 2018, the year that the DTaP-IPV-HepB-Hib was introduced in the NIP.
