The amount of time that passes between a symptomatic vivax malarial episode and a subsequent recurrence has in the past often been regarded as an indication as to whether the recurrence is a relapse (hypnozoite origin) or a recrudescence (merozoite origin). It should be noted that in the light of new knowledge and understanding, the time factor is not a valid criterion. (Link to first paper). (Link to second paper).
Comments
Drug failure in vivax malaria
In addition to directly providing miscellaneous information relevant to the temporal matter (but one should also read between the lines), the two publications include non-drug-resistance comments in relation to recurrences. It is unlikely that resistance is the only drug factor involved in treatment-compliant patients. Alternative possible causes of drug failure (leaving aside host genetic factors and drug dosage) need to be considered by researchers. For instance, the drug-associated implications of whereabouts in the body parasites occur.