Malaria prophylaxis

Malaria prophylaxis is the preventive treatment of malaria. 

For pregnant women who are living in malaria endemic areas, routine malaria chemoprevention is recommended. 

Bite prevention—clothes that cover as much skin as possible, insect repellent, insecticide-impregnated bed nets and indoor residual spraying.

Recent improvements in malaria prevention strategies have further enhanced its effectiveness in combating areas highly infected with the malaria parasite. 

Additional bite prevention measures include mosquito and insect repellents that can be directly applied to skin. 

Sanctions on blood transfusions, if the malaria parasite enters the erythrocytic stage, it can adversely affect blood cells, making it possible to contract the parasite through infected blood.

Chloroquine may be used where the parasite is still sensitive, however many malaria parasite strains are now resistant.

Mefloquine (Lariam), or doxycycline or the combination of atovaquone and proguanil hydrochloride (Malarone) are frequently recommended.

Chloroquine, proguanil, mefloquine, and doxycycline are suppressive prophylactics, that are only effective at killing the malaria parasite once it has entered the erythrocytic stage of its life cycle, and therefore have no effect until the liver stage is complete: these prophylactics must continue to be taken for four weeks after leaving the area of risk.

Mefloquine, doxycycline, and atovaquone-proguanil appear to be equally effective at reducing the risk of malaria for short-term travelers and are similar with regard to their risk of serious side effects.

Mefloquine is sometimes preferred due to its once a week dose, however mefloquine is not always as well tolerated when compared with atovaquone-proguanil.

Mefloquine and doxycycline are similar with regards to the number of people who discontinue treatments due to minor side effects.

People who take mefloquine may be more likely to experience minor side effects such as sleep disturbances, depressed mood, and an increase in abnormal dreams.

There is very low quality evidence indicating that doxycycline use may be associated with an increased risk of indigestion, photosensitivity, vomiting, and yeast infections, when compared with mefloquine and atovaquone-proguanil

Causal prophylactics target not only the blood stages of malaria, but the initial liver stage as well: the user can stop taking the drug seven days after leaving the area of risk. 

Malarone and primaquine are the only causal prophylactics in current use.

Specific regimens are recommended by the WHO:

doxycycline 100 mg once daily;started one day before travel, and continued for four weeks after returning

mefloquine 250 mg once weekly: started two-and-a-half weeks before travel, and continued for four weeks after returning.

atovaquone/proguanil (Malarone) 1 tablet daily; started one day before travel, and continued for one week after returning.

In areas where chloroquine remains effective:

chloroquine 300 mg once weekly, and proguanil 200 mg once daily started one week before travel, and continued for four weeks after returning.

hydroxychloroquine 400 mg once weekly, started one to two weeks before travel and continued for four weeks after returning.

The most appropriate regimen depends on the person who is to take the medication as well as the country or region travelled to. 

Other chemoprophylactic regimens that have been used on occasion:

Dapsone 100 mg and pyrimethamine 12.5 mg once weekly: this combination is not routinely recommended because of the risk of agranulocytosis.

Primaquine 30 mg once daily, started the day before travel, and continuing for seven days after returning: this regimen is not routinely recommended because of the need for G-6-PD testing prior to starting primaquine.

Quinine sulfate 300 to 325 mg once daily: this regimen is effective but not routinely used because of the unpleasant side effects of quinine.

A malaria vaccine known as RTS,S provides modest protection against both clinical and severe malaria in young infants: efficacy about 30% in infants 6 to 12 weeks of age and about 50% in infants 5 to 17 months of age in the first year of a vaccine trial.

Most adults from endemic areas have a degree of long-term infection, which tends to recur.

Most adults from endemic areas also possess partial immunity, but the resistance reduces with time, and such adults may become susceptible to severe malaria if they have spent a significant amount of time in non-endemic areas. 

Leave a Reply

Your email address will not be published. Required fields are marked *