Routine surveillance of adverse events following immunization as an important tool to monitor vaccine safety

Abstract

Post licensure surveillance of adverse events following immunization (AEFI) is a fundamental activity to improve safety and maintain public confidence in vaccines. Since 2011, the Liguria Region has been involved in the inter-regional project of post-marketing surveillance of AEFI, coordinated by the Italian Medicine Agency and the Veneto region. The main objectives of the project are: (1) to coordinate the surveillance activities in the 8 Italian Regions included in the project; (2) to encourage the signal of AEFI by healthcare workers and patients; (3) to organize education activities addressed to health care workers, and, finally; (4) to establish vaccination counseling services in each Region. In particular, the Ligurian multidisciplinary team, composed by physicians expert in the field of vaccination and pharmacists, is involved in the causality assessment between vaccines and all adverse events signaled within the Liguria Region and in the analysis of all adverse events signaled in Italy as possibly related to influenza vaccines. During 2013, the team has organized 4 courses, addressed to healthcare personnel of vaccination outpatient clinics, focused on European and Italian legislation on pharmaco-vigilance and vaccine-vigilance and aimed at promoting signal of AEFI. Since October 2013, the Liguria Region has been participating to the inter-regional project of active surveillance of adverse events aimed at promoting the signal of AEFI by parents of vaccinated infants. After two years of implementation of the project both the number of reported AEFI and the reporting rate per 100 000 administered doses of vaccine increased. The activities need to be consolidated in the next years in order to guarantee high standard of vaccine safety, maintain the confidence in current immunization programs and reach optimal vaccination coverage rate.

Safety of Co-Administration Versus Separate Administration of the Same Vaccines in Children: A Systematic Literature Review

“…Typically, safety was briefly described and one-third of studies lacked any statistical assessment of AEFI. Most of the studies were randomized clinical trials (RCTs) mainly designed to demonstrate efficacy, with sample sizes that were too small for assessing particularly rare and very rare adverse events with sufficient statistical power [49]. This may be a reason why studies failed to detect statistically significant differences in safety.…”

Post-marketing surveillance of adverse events following measles, mumps, rubella and varicella (MMRV) vaccine: retrospecive study in apulia region (ITALY), 2009-2017

“…Some studies about the use of causality assessment in the evaluation of safety profile of vaccines have been carried out in Italy but the systematic use of this evaluation is mandatory only since 2017. 13,14 In 2018, WHO published the last update of systematic and standardized causality assessment algorithm for serious AEFI to be used by the staff of national immunization programs, regulatory authorities, and pharmacovigilance or surveillance departments. 8 According to the WHO algorithm, the association between vaccine and AEFI can be considered not-classifiable when the forms lack of essential data (e.g., the name of the vaccine administered); consistent casual association or inconsistent causal association in presence or absence of a defined causal relationship between adverse event and immunization; indeterminate if there isn't clear evidence for a causal link, or conflicting trends, or inconsistency with causal association to immunization (this is a potential signal and needs to be considered for further investigation; reviewing factors result in conflicting trends of consistency and inconsistency with causal association to immunization, i.e., it may be vaccine-associated as well as coincidental and it is not possible clearly to favor one or the other).…”

Lactoferrin acts as an adjuvant during influenza vaccination of neonatal mice

“…We did not observe any detrimental effects after administering bLF to neonatal Balb/c mice. Vaccine experts are prospectively monitoring adverse effects of vaccination, especially influenza (24). Recently, investigators have attributed adverse events after vaccination to pre-existing neurologic disease (25).…”