Reduced Costs of Managing Adverse Reactions with DT3aP-HBV-IPV/Hib Versus DT2aP-HBV-IPV-Hib in Vietnam: Results of a Cross-Sectional Survey and Mathematical Projections of Vaccination of Infants

In Vietnam, hexavalent vaccines are routinely given during early childhood. Hexavalent vaccines DT3aP-HBV-IPV/Hib and DT2aP-HBV-IPV-Hib differ in composition and therefore, reactogenicity, with DT3aP-HBV-IPV/Hib shown to cause fewer adverse reactions (ARs) than DT2aP-HBV-IPV-Hib. Online surveys for physicians and parents/caregivers who manage post-vaccination ARs in children were used to explore AR management in the Vietnamese private healthcare setting. Survey data were used to estimate healthcare resource utilization (HCRU) and its associated costs, and indirect costs to parents/caregivers. A mathematical projection tool used survey results to approximate the difference in costs associated with post-vaccination childhood AR management following primary doses of DT3aP-HBV-IPV/Hib versus DT2aP-HBV-IPV-Hib. Parent/caregiver attitudes towards childhood vaccination in relation to management of ARs in their children were also explored. Around a third of parents/caregivers in Vietnam reported that their child experienced post-vaccination AR(s), the management of which led to significant HCRU and indirect costs to parents/caregivers. A primary dose of DT3aP-HBV-IPV/Hib compared with DT2aP-HBV-IPV-Hib led to 420 985 fewer ARs in Vietnam. Subsequently, HCRU burden and associated direct costs were reduced by ~11% and indirect costs to parents/caregivers were reduced by 14%. Parents/caregivers reported indirect costs of ~3 million VND per parent/caregiver per AR to manage ARs in their children. Additionally, parents/caregivers reported notable emotional concerns over ARs of rashes, diarrhea, and fever. However, despite costs and emotional burdens, most parents/caregivers did not express hesitancy toward future vaccinations. The substantial financial benefits of a vaccine with fewer ARs should be considered from a cost effectiveness perspective by decision-makers when evaluating vaccine alternatives.