Antimalarial prophylactic efficacy of a weekly dose atovaquone-proguanil
Malaria is a serious disease spread by mosquito bites. Travellers visiting tropical areas often take a preventative medicine called Malarone (atovaquone-proguanil). At the moment, Malarone must be taken every day, which can be difficult to remember. This early-stage study is testing whether taking Malarone once a week gives the same protection. Healthy adult volunteers will receive either the weekly medication or an inactive dummy pill (placebo). Under careful medical supervision, participants will then be exposed to a controlled, weakened dose of malaria parasites. Doctors will track volunteers closely using sensitive blood tests for at least three weeks. The aim is to see if weekly doses stop the parasites from multiplying in the blood. If any participant starts to develop malaria, doctors will immediately give them standard, effective medicines to cure the infection completely. The findings could make protecting travellers against malaria much easier.
At a glance
What is this study about?
Malaria is a life-threatening infection caused by tiny parasites that enter the blood through mosquito bites. Millions of people travel to areas where malaria is common each year. To stay safe, travellers often take preventative tablets. One of the most popular is Malarone, which combines two medicines: atovaquone and proguanil. However, people must take it every single day, and forgetting doses can leave them unprotected.
Researchers are running this trial to find out if taking Malarone just once a week is enough to stop malaria from developing. A weekly pill could make it far simpler for travellers and healthcare workers to stick to their prevention plan and stay healthy.
To test this, the trial uses a controlled human infection model. Volunteers receive their weekly tablets and are then exposed to malaria parasites in a carefully managed medical setting. Doctors check their blood frequently using highly sensitive laboratory tests. This allows researchers to see whether the weekly dose successfully blocks the parasite from growing before any serious illness can develop.
Key takeaways
- The trial tests if taking Malarone once a week prevents malaria as effectively as daily doses.
- Healthy adult volunteers aged 18 and older are needed.
- Participants will receive either weekly medication or a placebo, followed by a controlled exposure to malaria.
- Volunteers will be closely monitored with regular blood tests.
- Full, standard malaria treatment is given immediately if any parasites are detected.
Who may be eligible?
This study is open to healthy adults aged 18 and over. Because this trial involves a deliberate exposure to malaria parasites, participants generally need to be in good overall health with a well-functioning immune system.
You are unlikely to be able to take part if you have long-term health problems, such as heart, kidney, or liver conditions, or if you are pregnant or breastfeeding. People who have had malaria before or who have recently taken anti-malaria medicines may also be excluded, as this could affect the test results.
The research team will carry out detailed health checks, including blood tests and medical history reviews, to confirm whether taking part is safe for you.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- I am aged 18 or older.
- I am in good general health without major long-term illnesses.
- I am not currently pregnant, planning to become pregnant, or breastfeeding.
- I have not recently had malaria or taken anti-malaria medication.
- I am able to attend frequent clinic visits for blood tests over several weeks.
What does participation involve?
Taking part involves several stages over a few weeks or months. First, you will attend a screening visit to check your general health. If you are eligible, you will be given either the weekly Malarone tablets or matching dummy capsules (placebo). You will then receive a small, controlled dose of malaria parasites under strict hospital supervision.
After exposure, you will need to attend frequent clinic visits—often daily for a couple of weeks—for health checks and blood tests. Researchers use these tests to look for tiny traces of the parasite. If parasites are found, you will immediately be given standard, proven malaria medication that clears the infection quickly. The study team will follow your progress until you are completely clear and well.
Potential risks and benefits
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Common questions
Will I be deliberately infected with malaria?
Yes, but in a strictly controlled and safe medical environment. The dose is tiny, doctors monitor you daily, and reliable curative medicines are given immediately if the parasite appears.
What is Malarone?
Malarone is an existing, widely approved medicine used to prevent and treat malaria. This study is testing a new, weekly schedule rather than the standard daily dose.
What happens if I get sick?
Doctors check your blood continuously. If malaria parasites are detected—even before you feel unwell—you will receive standard anti-malaria medicines that cure the infection.
Can I choose whether I get the real tablet or the dummy pill?
No. A computer chooses at random to ensure the trial results are fair and unbiased. Neither you nor the study team will know which you received until the study ends.
Can I leave the study early?
Yes, you can leave at any point. However, because you are exposed to malaria, doctors will need to give you curative medicine to make sure you are completely safe.
How to find out more
Always speak to your GP or specialist before deciding to take part in a study.
Interested in taking part?
Discussion
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