This expert blog was contributed by Dr. Merlin Willcox, Honorary Secretary of the Research Initiative on Traditional Antimalarial Methods (RITAM), in response to the outcome of a poll on MalariaWorld and recent contributions regarding the use of Artemisia tea as a remedy for malaria.
Should Artemisia annua (wormwood) tea be used as a prophylactic in endemic countries?
As a scientist and medical doctor, I am interested in herbal medicines for malaria. No one can deny that they have been the source of the two most important and effective families of antimalarial drugs. Furthermore many people still rely on various herbal remedies for treating uncomplicated malaria. Much of my own research has aimed to investigate these objectively and to find the most effective remedies.
Artemisia annua is a very interesting plant and is the source of the most powerful antimalarial drug ever discovered, artemisinin. There are a few clinical trials which even show that it can be used as an “emergency, first-aid” treatment for malaria in semi-immune adults. However there are no published clinical trials which prove effect on the prevention of malaria, and no published clinical trials which demonstrate effectiveness in young children...
Some of the claims being made recently on the pages of MalariaWorld are questionable. For example: “A "vaccine" against malaria from Africa: ARTAVOL” claims that “The product has been released after clinical and community trials over 3 years which have demonstrated that if taken regularly during one year it renders a person immune against malaria.”
No such trials have been published. It is highly unlikely that taking ANYTHING for one year would render a person “immune” against malaria. Even the best vaccines have so far failed this test. The only thing which does seem to give some level of immunity is continued low-level exposure to malaria parasites. The claim is misleading and might distract people from proven interventions such as the use of insecticide-treated mosquito nets.
There are some interesting comments for and against the poll on this subject. I doubt whether use of Artemisia annua is a significant contributor to drug resistance, because the plant does contain other antimalarial compounds, and is not widely used in south-east Asia, where resistance has in fact occurred. However, it is misleading to say that “no resistance has been observed so far”. How do you define resistance? The trial of Mueller et al (2004) showed that many patients experienced a recrudescence of parasites after a treatment with Artemisia annua tea. This may not be resistance per se, but it does indicate that the tea is not as miraculous as some people claim.
The reason for being cautious about this approach, at least in my case, is not motivated by pharmaceutical companies’ greed. I have no conflicts of interest and no involvement with any pharmaceutical companies. My only interest, as a medical doctor, is to find the best treatment for patients, to prevent needless deaths from malaria, particularly in African children.
The fact of the matter is that so far, no published clinical trials have demonstrated that Artemisia annua tea is effective in the prevention or treatment of malaria in children. A few small trials have shown some effectiveness in the treatment of malaria in semi-immune adults. However young children do not have the same levels of immunity so the treatment may not be so effective in them. If there really is no other treatment available, it is probably better than nothing as a “first aid” option while looking for more effective ACTs. Although it is true that there are fake ACTs, the real ACTs are the most effective antimalarials currently available. It could be considered unethical to promote Artemisia teas at the expense of ACTs in young children.
Most of the studies quoted are poorly designed and have fundamental flaws in their design. For example if there is no control group, how can you know that the effect is real? If patients are only followed for 2 days instead of 28 days, how can you be sure that the treatment really prevented malaria? Variations in parasite counts occur commonly even without treatment.
It is time for us to work together on high-quality scientific research, to find and develop the most cost-effective treatments and prophylactics for malaria. I am convinced that there are good treatments and prophylactics waiting to be discovered and developed from the plant kingdom. Unfortunately it is difficult to find funding for this sort of research. The lack of evidence tends to polarise people into two camps – those “FOR” who enthusiastically promote herbal products with minimal evidence; and those “AGAINST” who denigrate herbs as being “unscientific” or “quackery”. It would be better to take a middle path, using high-quality scientific evidence and research to guide us to develop truly effective and safe antimalarial treatments and prophylactics. Meanwhile, when giving guidance to patients and NGOs, we would be wise to stick to what has actually been proven to work in high-quality clinical trials.
Mueller MS, Runyambo N, Wagner I, Borrmann S, Dietz K, Heide L.(2004). Randomized controlled trial of a traditional preparation of Artemisia annua L. (Annual Wormwood) in the treatment of malaria.Trans R Soc Trop Med Hyg., 98(5):318-321.