Characteristics of severe advert event following immunization cases in the expanded program in immunization and some related factors in Northern region of Vietnam, 2016 – 2020

Abstract

The study aims to describe characteristics of severe advert event following immunization cases in the expanded program in immunization and some related factors in Northern region of Vietnam, 2016 – 2020. The results showed that SAEs mainly were seen in the age group of 2 to 6 months. Most cases occurred within 12 hours after injection; only 0.51% of SAEs appeared after 72 hours. Cyanosis was seen in 60.4% of cases. More than 50% of patients were taken to a health facility within 30 minutes from their first symptoms. The majority of cases were treated with adrenaline after the onset of SAE; the mean duration from onset to adrenaline used was 177 minutes. The earliest case was immediately after symptoms when the latest case was after 2050 minutes. The under two-month-old group has a 6.5 times higher risk of death by SAE than the older group. Therefore, early medical attention and/or emergency use of adrenaline within 1 hour will reduce the risk of death by SAE.