Malaria: "we may have found a real arm to fight it"
September 24, 2012
Since July, MSF has been employing seasonal malaria chemoprevention (SMC) for the first time in two Sahelian countries. The initial results are encouraging, notably for the number of avoided cases. Dr. Estrella Lasry, malaria specialist at MSF, reflects on the different aspects and future prospects of this strategy.
What are the main considerations when employing this strategy?
It's the first intervention of this type we've ever run, so we had to delve into a number of medical and operational issues and read up on studies covering the subject and the World Health Organisation's (WHO) recommendation issued last March.
As a first step, we had to select which anti-malarial treatment to use. The combination of amodiaquine and sulphadoxine/pyrimethamine (Fansidar®) is known to be one of the most effective as it causes less side effects in children and guarantees relatively long coverage, averaging 28 days.
Then we decided to target children aged between 3 months and 5 years old. Immunity defence systems are less developed at this age, so young children are particularly vulnerable to the disease.
Lastly, we identified the most heavily indicated areas to get our work underway. The WHO recommends SMC as a malaria prevention strategy in countries with seasonal malaria, i.e. more than 60% of annual cases occur within four months or less. This is the case for the area roughly stretching between Senegal and the Central African Republic.
So we decided on Mali and Chad, where malaria is the first cause of consultation and infant mortality.
What results were you expecting?
Studies carried out in several countries in West Africa show that SMC can prevent up to 80% of simple malaria cases and 70% of severe ones. We have no benchmarks to refer to for our projects in Mali and Chad because this is a the first time we've tried the strategy out in real field conditions.
But the initial results seem comparable - we saw a 65% reduction in the number of simple cases in Mali in the week following the treatment's administration. Furthermore, the number of malaria-associated hospitalisations plummeted from 247 to 84 per week, amounting to a drop of 70%.
These are encouraging results, and we now have to measure their impact in collaboration with research institutes and epidemiologists.
Does SMC give hope for the eradication of malaria?
It's too early to say. This would entail periodic treatment of the entire population, including adults, because the parasite is transmitted from man to man by the bite of certain mosquitoes.
For now, we're focusing on reducing the number of malaria-associated deaths. Around 15% of infected children develop severe forms. If they do not receive timely care, they are almost bound to die. And even if they do receive adequate care, the lethality rate for severe malaria still stands at about 15%. If we want to reduce malaria-associated mortality, we have to try and reduce the number of cases among the most vulnerable group: young children.
Why don't we administer SMC in all areas where malaria is endemic?
As things stand, the seasonal nature of malaria in certain countries enables us to determine our interventions - it's just not feasible to administer treatments all year round. And even if the results are promising, we must exercise caution for now. It's a relatively onerous treatment which can cause side effects: for instance amodiaquine, one of the two molecules used, can be rejected or lead to vomiting in a child. Suphadoxine/pyrimethamine can also spark off allergic reactions, such as the Stevens-Johnson syndrome. It's rare (1.2 cases per 100,000 exposures to the medicine), but calls for surveillance nonetheless. We also have to monitor the evolution of resistance to the molecules used, which could develop in 3 or 4 years time.
Lastly, the cost of the treatment currently stands at 0.5 US $ per child per month. This may seem low when taken per head, but seriously mounts up when distributed at a national scale.
To summarise, we must be cautious, we have to evaluate the strategy's impact, even if the initial results are incredible and spur us all on to replicate the project worldwide!
But at least we have the prospect of having found a real arm to fight this disease, which kills hundreds of thousands of people every year.