Effectiveness of twice a week prophylaxis with atovaquone-proguanil (Malarone®) in long-term travellers to West Africa.
BACKGROUND
Current guidelines recommend daily dosing of atovaquone-proguanil (AP), beginning a day before travel to endemic areas and continuing for 7 days after departure. Adherence of long-term travellers to daily malaria chemoprophylaxis tends to be poor, even when residing in highly endemic malaria regions. Evidence from a volunteer challenging study suggests that non-daily, longer intervals dosing of AP provides effective protection against Plasmodium falciparum This study examines the effectiveness of twice weekly AP prophylaxis in long-term travellers to highly endemic P. falciparum areas in West Africa.


METHODS
An observational surveillance study aimed to detect prophylactic failures associated with twice weekly AP, during the years 2013-2014, among long-term expatriates in two sites in West Africa. The expatriates were divided according to the malaria prophylaxis regimen taken: AP twice weekly; mefloquine once weekly and a group refusing to take prophylaxis. Malaria events were recorded for each group. The incidence-density of malaria was calculated by dividing malaria events per number of person-months at risk.


RESULTS
Among 122 expatriates to West Africa the malaria rates were: 11.7/1000 person-months in the group with no-prophylaxis (n = 63); 2.06/1000 person-months in the 40 expatriates taking mefloquine (P = 0.006) and no cases of malaria (0/391 person-months, P = 0.01) in the twice weekly AP group (n = 33).


CONCLUSIONS
No prophylaxis failures were detected among the group of expatriates taking AP prophylaxis twice weekly compared with 11.7/1000 person-months among the no-prophylaxis group. Twice weekly AP prophylaxis may be an acceptable approach for long-term travellers who are unwilling to adhere to malaria chemoprophylaxis guidelines.
The Infectious Diseases Unit, Shaare-Zedek Medical Center, P.O.B 3235, Jerusalem 91301, Israel lachisht@yahoo.com.
Tamar
T
Lachish
The Infectious Diseases Unit, Shaare-Zedek Medical Center, P.O.B 3235, Jerusalem 91301, Israel.
Maskit
M
Bar-Meir
Centro Médico La Paz, Malabo, Equatorial Guinea.
Neta
N
Eisenberg
The Center for Geographic Medicine, the Chaim Sheba Medical Center, Tel-Hashomer, Israel, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Eli
E
Schwartz
D017954:Africa South of the Sahara; D000354:Africa, Western; D000962:Antimalarials / Q000627:therapeutic use*; D053626:Atovaquone / Q000627:therapeutic use*; D018890:Chemoprevention / Q000379:methods*; D004338:Drug Combinations; D004359:Drug Therapy, Combination; D019353:Endemic Diseases / Q000517:prevention & control*; D006801:Humans; D008288:Malaria / Q000517:prevention & control*; D002727:Proguanil / Q000627:therapeutic use*; D014195:Travel
D000962:Antimalarials; D004338:Drug Combinations; C109496:atovaquone, proguanil drug combination; D002727:Proguanil; D053626:Atovaquone
Atovaquone–proguanil; expatriates; malaria chemoprophylaxis; mefloquine; travellers