A study was conducted to assess the safety and tolerability of the tetravalent live-attenuated dengue vaccine Qdenga®, which received marketing approval in Germany in 2022. The study evaluated vaccine-related reactions in a predominantly dengue-naïve population, highlighting the importance of post-marketing surveillance as an essential component of safety evaluation for newly licensed vaccines.
Following dengue vaccination, participants were recruited for an anonymous online questionnaire through the national ‘Trav VacNet’ network in Germany. The questionnaire focused on post-vaccination reactions up to 18 days after the first and second vaccination, as well as previous travel history and coadministration.
The study included 1176 participants, with a median age of 39 years (IQR 28-56), 53.2% female (n = 625), 46.5% male (n = 547), and 0.3% non-binary participants (n = 4). After the first dose, 51% of the participants reported systemic reactions such as headache (40% (190/474)), weakness (40% (189/474)) and malaise (32% (154/474)), which were most pronounced between days 7-11 post vaccination. After the second dose, localized signs and symptoms such as pain at the injection site (22% (n = 55/250)) were more common. Fever was more common after the first dose (20% (96/474)) vs. 2% (6/250) after the second. Females reported significantly more reactions than males after both vaccinations (1st dose p = 0.0002; 2nd dose p = 0.0003). A total of 334 (28%) co-administrations were reported whereby AEs were reported in 47% (157/333) of participants, with the highest prevalence observed when combined with the Japanese encephalitis vaccine (56.8%, (42/74)). Differences in age groups were observed, with a decrease in reactions in the elderly (≥65 years).
Vaccine-related reactions were frequently reported, predominantly after the first dose in dengue-naïve participants. Coadministration was a common strategy without significantly increasing side effects. The study provides important insights into reactogenicity and may help improve vaccination strategies in dengue-naïve populations.
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