Delayed rabies post-exposure prophylaxis treatment among Dutch travellers during their stay abroad: a comprehensive analysis

Background: After an animal-associated injury (AAI) in rabies-endemic regions, post-exposure prophylaxis (PEP) is needed to prevent infection.(1,2) PEP consists of rabies vaccinations (RV) and in some cases also additional rabies immune globulins (RIG). Not always PEP medication, and RIG in particular, is accessible. Along with an increased number of exposure notifications among Dutch travellers, this might lead to treatment delay and thus to increased health risks. Until now, research mainly focused on factors associated with exposition, but none on which factors are associated with PEP delay. This study aimed to identify which general sample characteristics are associated with PEP delay while being abroad. Methods: A quantitative retrospective observational study was conducted. The study population consisted of insured Dutch international travellers who actively contacted their medical assistance company (2015-2019) because of an animal-associated injury (AAI) (N = 691). The association between general sample characteristics and delay of different PEP treatments was studied using survival analysis. Results: Travellers without pre-exposure prophylaxis (PrEP) had an increased hazard, and therefore a shorter delay, for receiving their first RV as compared to travellers with PrEP (HR:1.11, 95%CI:1.01-1.22). The travellers needing both RV and RIG had a decreased hazard, and therefore a longer delay, as compared to travellers only needing RV (HR:0.81, 95%CI:0.67-0.96). General sample characteristic associated with RIG administration delay was travel destination. Travellers to Central and South America, East Mediterranean and Europe had a decreased hazard, and therefore a longer delay, for receiving RIG treatments relative to travellers to South East Asia (HR:0.31, 95%CI:0.130.70; HR:0.34, 95%CI:0.19-0.61; HR:0.46, 95%CI:0.24-0.89; HR:0.48, 95%CI:0.12-0.81, respectively). Conclusions: Our results suggest that the advice for PrEP should be given based on travel destination, as this was found to be the main factor for PEP delay, among travellers going to rabies-endemic countries.