Eight studies (five randomised controlled trials and three uncontrolled studies) were included in the review. Sample sizes were reported in only three studies (a total of 630 participants) and ranged from 158 to 297. Five studies failed to report whether sample sizes were based on calculations of statistical power. Internal validity was reported as good in two studies and adequate in a further two studies; the internal validity of two other studies was reported as negative or threatened. External validity was reported as good in two studies and adequate in another; however, the remaining studies included participants from endemic or high-risk areas, which suggested that the study findings may not be applicable to other populations.
Prophylactic efficacy of atovaquone/proguanil was 97% against P. falciparum (one study) and 93-95% against all Plasmodium species (two studies). Reported adverse events included stomatitis and a flu-like syndrome.
Efficacy of tafenoquine against P. falciparum ranged from 68% to 89% dependent on dosage; the most effective regimen was 400mg/day for three days followed by 200mg per week. However, tafenoquine was associated with haemolytic events in patients with G6PD deficiency and mild gastrointestinal disorders.
Efficacy of primaquine against all Plasmodium species was 93%. A number of reported adverse events included haemolytic events and toxinemia. None of the participants who received mefloquine or doxycycline contracted malaria (one study), but both regimes were associated with gastrointestinal and neurological disorders, amongst other adverse events.
Study withdrawals due to adverse events included: 2/223 with tafenoquine (one study); 2/158 with primaquine (one study); 12.5% with doxycycline (one study); 4.6% with mefloquine (one study); and 3/175 and 4/150 with atovaquone/proguanil (two studies)