Characteristics of Adverse Events Following Immunization Reporting in Children: The Japanese Adverse Drug Event Report Database.

Aoi Noda,Takamasa Sakai,Nariyasu Mano,Taku Obara,Masami Tsuchiya,Gen Oyanagi

doi:10.3390/vaccines8030357

Abstract

The present study aimed to describe the trends and characteristics of adverse events following immunization (AEFI) reporting for children in the Japanese Adverse Drug Event Report database (JADER). We used 6280 AEFI reports for children aged <19 years among 504,407 ADR reports included in the JADER from 2004 to 2017. The number of AEFI reports gradually increased among children aged <10 years and was the highest in 2011 among children aged 10–19 years. The number of suspected vaccines per AEFI report increased after 2011 among children aged <10 years. The percentage of “death” and “did not recover” as AEFI outcomes reported were 4.3% and 3.7% among children aged <10 years and 0.2% and 21.1% among children aged 10–19 years, respectively. The most frequently reported vaccine–reaction pair was Haemophilus influenzae type b conjugate vaccine and pyrexia among children aged <10 years and recombinant adsorbed bivalent human papillomavirus-like particle vaccine and a loss of consciousness among children aged 10–19 years. It is necessary to consider the Weber effects to understand the trend and characteristics of AEFI reporting because pharmacovigilance activity regarding vaccination is not sufficient in Japan.

Highlights

Vaccines are the most widely used medicine in children worldwide
A total of 504,407 adverse drug reaction (ADR) reports from April 2004 to December 2017 were downloaded from the Japanese Adverse Drug Event Report database (JADER) in April 2018
It was difficult to estimate the number of children that received the vaccines because vaccinations are not covered by health insurance and they do not remain as health insurance claims data, and, even for vaccinations

Summary

Introduction

Vaccines are the most widely used medicine in children worldwide. They are usually administered to patients and to healthy individuals, and serious adverse events following immunization (AEFI) rarely occur. Because there are many types of vaccines, including combination and live vaccines, the appearances and types of adverse reactions are diverse, especially in children. Several studies have been carried out to describe the trends and characteristics of adverse drug reaction (ADR) reports, including vaccine reports, to evaluate the quantity and quality of Vaccines 2020, 8, 357; doi:10.3390/vaccines8030357 www.mdpi.com/journal/vaccines. It is necessary to describe the trends and characteristics of AEFI reporting in the Japanese spontaneous reporting system to understand what is happening regarding vaccines

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