Malaria Vaccine : Close to Reality?
Malaria is a parasitic infection transmitted by mosquitoes. Almost half the world’s population — or 3.3 billion people — are at risk of malaria and there are around 225 million cases each year. Most at risk are in the world’s poorest countries.
Symptoms of malaria include fever, headache and vomiting, and usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs.
Most affected region: Africa
Most of the almost 800,000 annual deaths from malaria are among children in Africa under the age of five. More than 90 percent of cases are caused by plasmodium falciparum, the most destructive malaria parasite that is found mainly in Africa. Malaria accounts for around 40 percent of public health spending in sub-Saharan Africa. Malaria-related illnesses and deaths are estimated to cost Africa’s economy $12 billion a year and the disease can cut gross domestic product by as much as 1.3 percent in countries with high disease rates, such as Nigeria and the Democratic Republic of Congo.
Treating mosquito nets and houses with insecticides is one of the major prevention strategies, but mosquitoes can develop resistance to insecticides, making them ineffective. Antimalarial medicines are also very effective. But growing resistance to older antimalarials has spread rapidly, undermining efforts to control the disease.
An experimental malaria vaccine called RTS,S or Mosquirix is in the final stages of clinical testing in around 16,000 children in Africa. The vaccine, which was shown to be around 50 percent effective in earlier trials, is being developed by British drug maker GlaxoSmithKline with money from the Bill and Melinda Gates Foundation-funded PATH Malaria Vaccine Initiative. The trial was conducted at 11 trial sites in seven countries across sub-Saharan Africa.
- The 7 countries are Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania.
The trials became Africa’s largest-ever medical experiment as the vaccine was tested in around 16,000 children across seven countries. This is one of the final stages in evaluating the efficacy and safety of the vaccine candidate in infants and young children on a large scale before regulatory file submission. Bill Gates called this discovery a “huge milestone” in the fight against malaria.
- RTS,S is the first vaccine designed primarily for use in Africa. Please note that earlier SPf66 was tested extensively in endemic areas in the 1990s, but clinical trials showed it to be insufficiently effective.
Is there any country that eliminated Malaria?
Yes. Maldives is the only country among the developing countries that has eliminated malaria, while Sri Lanka and Korea are in the pre-elimination stage. The remaining eight countries, including India, are trying to control regular outbreaks. Bhutan and Thailand have large areas with no malaria transmission and have expressed their intention to proceed with elimination joining the Asia Pacific Malaria Elimination Network(APMEN).
Why no vaccine against Malaria till now?
The malaria parasite is quite successful at avoiding the immune system because it works by infecting red blood cells and multiplying inside them, so they’re protected from a person’s immune system while they’re sort of hiding inside our own cell. Then they burst out of it in greater numbers and very rapidly infect other surrounding blood cells. Also they very rapidly mutate and evolve, while a given drug may wipe out most of a population of the parasites, some will survive and grow back in greater numbers, most of which are now resistant to the drug we used in the first place. So, the reasons are:
- They hide in patient’s own cells
- They replicate very fast
- They become drug resistant very soon.
But How RTS’S overcomes these issues?
RTS’S vaccine goes to work at the point when the parasite enters the human bloodstream after a mosquito bite. By stimulating an immune response, it can prevent the parasite from maturing and multiplying in the liver. Without that immune response, the parasite re-enters the bloodstream and infects red blood cells, leading to fever, body aches and, in some cases, death.
Who is Joe Cohen?
Joe Cohen is a GlaxoSmithKline research scientist who has spent 24 years trying to create the world’s first malaria vaccine. For him, Tuesday, October 18, 2011 goes down as a fabulous day.His RTS,S, also known as Mosquirix, showed it halved the risk of African children getting malaria, making it likely to become the world’s first successful vaccine against the deadly disease. Although Cohen’s scientific work has been largely in Belgium, where he runs a GSK laboratory, the final-stage trials of RTS,S were conducted in Africa, where malaria hits hardest. Cohen says that if all goes to plan, RTS,S could be licensed and rolled out by 2015.