The persistence of Plasmodium vivax continues to be a barrier to malaria elimination. This is largely due to the ability of P. vivax to sequester within liver cells, resulting in asymptomatic infections that cannot be detected by current diagnostics. Dormant liver parasites, known as hypnozoites, can activate and cause infection relapse, thus sustaining onwards community transmission. Detection of these silent infections is crucial to identify hidden reservoirs and accelerate towards malaria elimination. Validated panels of serological exposure markers (SEMs) can identify individuals with prior P. vivax exposure who may be harbouring hypnozoites. We assessed whether this approach could be used to identify hidden P. vivax reservoirs in an area of Papua New Guinea (PNG) that had experienced a decline in malaria transmission following a period of intensified control measures. We applied this SEM panel to 395 plasma samples from young children aged 1-5 years collected during a longitudinal cohort study in 2012-2013 in East Sepik Province (ESP), PNG to predict whether children had experienced recent P. vivax exposure (and likely harboured hypnozoites), as well as measure the ability of SEMs at enrolment to predict risk of recurrent P. vivax infections. Of the 12 villages surveyed, three were found to have significantly higher proportions of children classified as having prior exposure to P. vivax, confirming heterogeneous spatial clusters of P. vivax infections in ESP. Importantly, children that were predicted to be recently exposed to P. vivax had a significantly higher risk of recurrent infections (RR=2.61) during the follow-up period (median of 5 new P. vivax infections) compared to those with no recent exposure (median of 0 new infections). These findings demonstrate the utility of SEMs to identify hidden reservoirs of P. vivax infections and children at high risk of recurrent infections.