Only a "few" hypnozoites occur in patients who have Plasmodium vivax infections, compared to the large, non-circulating merozoite biomass that is now known to be present.
Therefore, to readily ascribe P. vivax malarial recurrences to hypnozoite activation, as is currently common practice, is no longer appropriate without good reasons for doing so. Forget about what you were taught at university in this context and keep an open mind.
It must now be assumed that as regards non-circulating parasite sources of recurrent P. vivax malaria, there is both (unless proved otherwise in the future) a hypnozoite and a merozoite origin – the latter certainly in early recurrences, probably. Thus, some recurrences will be relapses, whereas others will be recrudescences that have a non-bloodstream, tissue merozoite origin.
The bottom line is that recurrence of P.vivax malaria is partly a poorly understood, extravascular/sequestered parasite numbers-associated phenomenon. Hypnozoites are very much in the minority (ref. the first paragraph above).
For further information, see: