How to prevent malaria

Learn everything you need to know about malaria prophylaxis (and vaccines) in this Medmastery article.
Last update29th Apr 2021

Is it possible to prevent malaria in the first place?

Although there are several anti-malarial drugs, there isn’t one that’s 100% effective, so it’s important to take personal protective measures such as wearing insect repellent, long sleeves and pants, sleeping in a mosquito-free setting, or using an insecticide-treated bed net. With this in mind, let’s take a closer look at the available oral anti-malarials.

Oral anti-malarial prophylaxis

As anyone who has traveled to an area with endemic malaria knows, it is important to take anti-malarial prophylaxis. Because the mosquitoes in these areas are so prevalent, it’s almost a guarantee that travelers will end up exposed to malaria. So, these prophylactic medications generally don’t actually prevent a person from being infected with malaria, but instead they are treating the malaria that the traveler is almost certain to contract.

Anti-malarial prophylaxis can be taken daily or weekly.

Daily anti-malarial prophylaxis

There are three medications that travelers should take daily:

  1. Atovaquone-proguanil
  2. Doxycycline
  3. Primaquine

Atovaquone-proguanil

The combination of atovaquone and proguanil is given as prevention for Plasmodium falciparum malaria. But some falciparum malaria are resistant to atovaquone, so this may not be the ideal combination for individuals travelling to certain areas. Additionally, this combination cannot be used by women who are pregnant or breastfeeding a child less than 5 kg.

Figure 1. Atovaquone-proguanil should not be used as anti-malarial prophylaxis for women who are pregnant or breastfeeding a child less than 5 kg.

Doxycycline

Doxycycline tends to be the least expensive anti-malarial. It is also good for last-minute travelers because the drug is started one to two days before traveling to an area where malaria transmission occurs.

Doxycycline use comes with an increased risk of sun sensitivity so avoid considerable sun exposure when taking it.

Pregnant women and children under 8-years-old should not use this drug.

Figure 2. Doxycycline should not be used in pregnant women, children less than 8-years-old, and prolonged sun exposure should be avoided.

Primaquine

Primaquine is one of the most effective medicines for preventing P. vivax, so it is a good choice for travel to places with > 90% P. vivax prevalence.

But primaquine cannot be used in patients with glucose-6-phosphatase dehydrogenase (G6PD) deficiency or in patients who have not been tested for the deficiency. Primaquine should also not be used by pregnant women or in women who are breastfeeding unless the infant has also been tested for G6PD deficiency.

Figure 3. Primaquine cannot be used as anti-malarial prophylaxis in patients with glucose-6-phosphatase dehydrogenase (G6PD) deficiency, patients who have not been tested for G6PD deficiency, pregnant women, or women who are breastfeeding an infant who has not been tested for G6PD deficiency.

Weekly anti-malarial prophylaxis

Some people would prefer a weekly dose instead of daily, especially during a long trip. So, in addition to daily options, we have two weekly anti-malarial prophylaxis medications to consider:

  1. Chloroquine
  2. Mefloquine

These medications have the added benefit of being safe for use in pregnancy.

Figure 4. Chloroquine and mefloquine are safe for use in all trimesters of pregnancy.

Chloroquine

Chloroquine is a good choice when weekly dosing is preferred. But some strains of malaria will be resistant to chloroquine, so it cannot be used in areas where chloroquine-resistant malaria is found.

Mefloquine

Mefloquine is another weekly medication. However, at prophylactic doses, it has been associated with rare but serious adverse reactions, such as psychosis or seizures.

Figure 5. Prophylactic doses of mefloquine have been associated with rare but serious adverse reactions such as psychosis or seizures.

So, there are several options for anti-malarial prophylaxis we can choose based on the traveler’s preference, destination, contraindications, and precautions of the medications.

Figure 6. Common oral anti-malarial prophylaxis dosing intervals, contraindications, and precautions.

Anti-malarial vaccines

So, what about vaccines?

Most current research is focused on anti-sporozoite vaccines where attenuated sporozoites are injected to try to prevent the initial infection of liver cells by the parasites. While these are promising, they are all still in experimental stages.

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Recommended reading

  • Ashley, EA, Phyo, AP, and Woodrow, CJ. 2018. Malaria. Lancet391: 1608­–1621. PMID: 29631781
  • Fairhurst, RM and Wellems, TE. 2014. “Malaria (Plasmodium Species)”. In: Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, edited by Bennett, JE, Dolin, R, Blaser, MJ. 8th edition. Philadelphia: Elsevier Saunders. (Fairhurst and Wellems 2014, 3070–3090)
  • Phillips, MA, Burrows, JN, Manyando, C, et al. 2017. Malaria. Nat Rev Dis Primers3: 17050. PMID: 28770814
  • World Health Organization. 2015. Guidelines for treatment of malaria third edition. World Health OrganizationWorld Health Organization
  • World Health Organization. 2019. World malaria report 2019. World Health Organizationhttps://www.who.int

About the author

John F. Fisher, MD MACP FIDSA
Professor of Medicine (Infectious Diseases) at the Medical College of Georgia, Augusta University, USA.
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