Active surveillance of adverse events following immunization (AEFI): a prospective 3-year vaccine safety study

Abstract

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.

How were DTP-related adverse events reduced after the introduction of an acellular pertussis vaccine in Chile?

“…In this period of concomitant use, a lower rate of AEFI reports was observed; however, this direct comparison between aP (first and second doses) and wP vaccines (third and booster doses) should be avoided, since clinical trials have shown a higher reactogenicity in the first doses. [15][16][17] Several studies on vaccine hesitancy have shown that the safety profile and AEs can be a barrier and discourage vaccination and increase hesitancy. 18 Various studies, including in Chile, have shown that wP pentavalent vaccines are responsible for most AEFI in children and that the group with the highest frequency of reported AE are infants under 1 year of age, due to the fact that they receive the greatest number of vaccines.…”

Vigilância ativa de eventos adversos pós-vacinação na atenção primária à saúde

“…A alta incidência pode estar associada à imaturidade do sistema imunológico e ao alto número de vacinas administradas nessa faixa etária. (17)(18)(19)(20) Entre os eventos locais e sistêmicos identificados, a dor e a febre foram os mais incidentes. A maioria dos eventos adversos pós-vacinação, locais e sistêmicos, são leves e autolimitantes (8,9,17,21) e representam a área de atuação da equipe de enfermagem, uma vez que, nas unidades de APS públicas brasileiras, ela é a principal responsável pelas atividades de vacinação.…”

“…Profissionais de saúde com conhecimento são capazes de informar os indivíduos sobre a importância e os benefícios da vacinação e sobre os possíveis riscos e a ocorrência de eventos adversos pós-vacinação. (16,20) O fornecimento dessas informações à população, chamado de triagem vacinal, é recomendado como atividade básica a ser realizada nas salas de vacinação. (10) A triagem vacinal é uma medida específica para evitar riscos na vacinação, pois, além de permitir o monitoramento do status vacinal dos indivíduos e de seus históricos de saúde, é quando o profissional de saúde tem a oportunidade de realizar aconselhamentos sobre as vacinas e seus possíveis EAPV.…”

Using Population-Based Structures to Actively Monitor AEFIs during a Mass Immunization Campaign—A Case of Measles–Rubella and Polio Vaccines

“…The MR vaccine used in the immunization programs (prequalified by WHO) is a live-attenuated vaccine containing the Edmonston strain of measles and the RA 27/3 strain of rubella [17]. Prospective studies that used a similar product found incidence ranging from 13.7% to 20.8% [18,19]. However, one used a smaller sample size of 278 [18], and the other was conducted over a period of three years [19].…”

“…Prospective studies that used a similar product found incidence ranging from 13.7% to 20.8% [18,19]. However, one used a smaller sample size of 278 [18], and the other was conducted over a period of three years [19].…”