We included 14 trials, that enrolled 2592 participants, and were all conducted in Asia and Oceania between 2002 and 2011. ACTs versus
chloroquine: ACTs clear parasites from the peripheral blood quicker than
chloroquine monotherapy (parasitaemia after 24 hours of treatment: RR 0.42, 95% CI 0.36 to 0.50, four trials, 1652 participants, high quality evidence).In settings where
chloroquine remains effective, ACTs are as effective as
chloroquine at preventing recurrent parasitaemias before day 28 (RR 0.58, 95% CI 0.18 to 1.90, five trials, 1622 participants, high quality evidence). In four of these trials, recurrent parasitaemias before day 28 were very low following treatment with both
chloroquine and ACTs. The fifth trial, from Thailand in 2011, found increased recurrent parasitaemias following treatment with
chloroquine (9%), while they remained low following ACT (2%) (RR 0.25, 95% CI 0.09 to 0.66, one trial, 437 participants).ACT combinations with long half-lives probably also provide a longer prophylactic effect
after treatment, with significantly fewer recurrent parasitaemias between day 28 and day 42 or day 63 (RR 0.57, 95% CI 0.40 to 0.82, three trials, 1066 participants, moderate quality evidence). One trial, from Cambodia, Thailand, India and Indonesia, gave additional
primaquine to both treatment groups to reduce the risk of spontaneous relapses. Recurrent parasitaemias after day 28 were lower than seen in the trials that did not give
primaquine, but the ACT still appeared to have an advantage (RR 0.27, 95% CI 0.08 to 0.94, one trial, 376 participants, low quality evidence). ACTs versus alternative ACTs: In high transmission settings,
dihydroartemisinin-
piperaquine is probably superior to
artemether-lumefantrine,
artesunate plus
sulphadoxine-pyrimethamine and
artesunate plus
amodiaquine at preventing recurrent parasitaemias before day 28 (RR 0.20, 95% CI 0.08 to 0.49, three trials, 334 participants, moderate quality evidence).
Dihydroartemisinin-
piperaquine may also have an improved post-treatment prophylactic effect lasting for up to six weeks, and this effect may be present even when
primaquine is also given to achieve radical cure (RR 0.21, 95% CI 0.10 to 0.46, two trials, 179 participants, low quality evidence).The data available from low transmission settings is too limited to reliably assess the relative effectiveness of ACTs.
AUTHORS' CONCLUSIONS: ACTs appear at least equivalent to
chloroquine at effectively treating the blood stage of P. vivax
infection. Even in areas where
chloroquine remains effective, this finding may allow for simplified protocols for treating all forms of
malaria with ACTs. In areas where
chloroquine no longer cures the
infection, ACTs offer an effective alternative.Dihydroartemisinin-
piperaquine is the most studied ACT. It may provide a longer period of post-treatment prophylaxis than
artemether-lumefantrine or
artesunate plus
amodiaquine. This effect may be clinically important in high transmission settings whether
primaquine is also given or not.