A cross-sectional survey to evaluate prescribers' knowledge and understanding of safety messages following Dengvaxia® product information update

Abstract

Purpose: We evaluated the effectiveness of additional risk minimisation measures (aRMMs; i.e., educational materials) distributed to prescribers to ensure that only individuals with evidence of prior dengue infection (PDI, i.e., dengue seropositive) would be vaccinated with the tetravalent dengue vaccine (CYD-TDV; Dengvaxia®).

Methods: A survey was conducted in 2020 among 300 CYD-TDV prescribers in Brazil and Thailand to ascertain three success criteria: prescribers' awareness of the materials (receiving and reading them); knowledge of the key messages; and whether their self-reported behaviour regarding practice-related scenarios was aligned with the updated guidance.

Results: The aRMMs were not generally effective as <80% of prescribers in both countries met two of the three predefined success criteria. In Brazil, 98.7% were aware of the aRMMs whereas in Thailand this criterion was fulfilled by 74.0%. Almost all prescribers knew that CYD-TDV was recommended only in individuals with PDI (98.7% and 96.7% in Brazil and Thailand, respectively). In Brazil, where vaccination was restricted to those with a documented history of PDI, 11.3% considered that confirmation should be done through a blood test. More than 75% in both countries considered additional signs of dengue, as early warning signs, and not only those regarded as such by the 2009 WHO guidelines.

Conclusions: These results do not support that the aRMMs were effective as the predefined success criteria were not met. The use of reliable rapid diagnosis tests together with the revised prescribing information and educational materials will facilitate the implementation and compliance with pre-vaccination screening for CYD-TDV eligibility.

Keywords: Dengvaxia; dengue; post-authorisation safety study; prescribing behaviour; risk minimisation measures; vaccine.

FIGURE 1

Analysis of the three outcomes success criteria separately and per speciality in Brazil. Confidence intervals are presented as “whiskers” on the bar for “All” category. Criterion of success No 1: Awareness—Prescribers with at least 1 of 2 questions successfully answered. Criterion of success No 2: Knowledge—Prescribers with at least 3 of 4 questions successfully answered. Criterion of success No 3: Behaviour—Prescribers with the 2 questions successfully answered. Since these 3 criteria are independent, the total could exceed 100%. The threshold for considering each outcome successful was ≥80% of prescribers meeting the success conditions (dashed line).

FIGURE 2

Analysis of the three outcomes success criteria separately and per speciality in Thailand. Confidence intervals are presented as “whiskers” on the bar for “All” category. Criterion of success No 1: Awareness—Prescribers with at least 1 of 2 questions successfully answered. Criterion of success No 2: Knowledge—Prescribers with at least 3 of 4 questions successfully answered. Criterion of success No 3: Behaviour—Prescribers with the 2 questions successfully answered. Since these 3 criteria are independent, the total could exceed 100%. The threshold for considering each outcome successful was ≥80% of prescribers meeting the success conditions (dashed line).