Malaria Conference addresses RTS,S vaccine, tools, treatment

Nov 3 2009

On Tuesday at the 5th Multilateral Initiative on Malaria (MIM) Pan-African Conference in Nairobi, Kenya, scientists and global health experts focused on malaria eradication, Agence France-Presse reports. "Key among the strategies ... is the development of an effective anti-malaria vaccine, a project scientists have been researching since the late 80s. ... RTS,S is the most clinically advanced malaria vaccine so far, according to the Malaria Vaccine Initiative," the news service writes (11/3). 

A press release from GlaxoSmithKline Biologicals, the PATH Malaria Vaccine Initiative and others partnering on the trial said that Phase III trials of RTS,S are "now underway in seven African countries: Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania." It added, "The trial, which is expected to involve up to 16,000 children, is on schedule, with more than 5,000 children already enrolled" (11/3).

"In Phase II trials, the RTS,S vaccine showed a 53% reduction in clinical episodes of malaria for eight months in children 5 to 17 months old last year, and in August, a trial in Mozambique of kids aged 1 to 4 years suggested that the vaccine is capable of providing protection for up to 45 months, but at a lower efficacy," the Scientist reports. "Of course 53% is not ideal," said Nirbhay Kumar of the Johns Hopkins Malaria Research Institute, who is not involved in the study. "The world would like to see 80 to 90% efficacy and slightly longer lasting [effects], but clearly the research is moving in a positive direction" (Akst, 11/3). 

According to the Associated Press/ABC News, "If regulators determine the vaccine is safe, it could be on the market in three to five years — the first vaccine against a human parasite." Although the vaccine was specifically developed to prevent the African strain of the disease and will not protect people in other malaria-endemic regions, "[e]xperts say it would be a historic advancement."

Joe Cohen, a GlaxoSmithKline researcher, said test results have been promising so far. "No prices have been set for the vaccine, Cohen said, though families in Africa may not have to pay anything for it because the [Bill & Melinda] Gates Foundation, UNICEF, WHO and the GAVI Alliance would provide funds. GlaxoSmithKline 'is committed to making sure pricing will never be a barrier to access for this vaccine,' Cohen said" (Straziuso, 11/3).

Samuel Kariuki, deputy chief researcher of the vaccine trials, said, "We expect that this vaccine will have a tremendous effect in the reduction of the number of admissions we see in the hospital and the number of deaths that occur due to malaria, especially in young children," Al Jazeera reports (11/3).

WHO Official Discusses Emerging Vector Resistence To ITNs In Some Parts Of Africa

Also at the conference, Jonathan Lines, a WHO coordinator for vector control and prevention, said some vector resistance to insecticide-treated nets had been detected in Benin, Cameroon, and on the Uganda-Kenya border, Capital News reports. "There are just signs that when you expose the mosquitoes, they are not dying as they should  but we are not yet sure whether this means treated mosquito nets will not work in that area," Lines said.

He added, "We have known one form of pyrathroid resistance for about nine years, one in Western Kenya (of a not very strong kind) and another in West Africa and we have been tracking that." He attributed the resistance to a lack of routine surveillance. Lines said effective vector control was still possible and recommended that the situation be monitored (Karong'o, 11/2).

Diagnosing And Treating Malaria

The Daily Nation/allAfrica.com reports on malaria testing technologies on display at the conference. Rapid testing kits, which the WHO is testing in five countries, "could help shift diagnoses from the current hit or miss management to treating only the confirmed cases," the Daily Nation/allAfrica.com writes.

The article also reports on conference discussions about the cost of malaria drugs. "Speaking at the ongoing international conference on Monday, the director of Malaria Control Team at the Clinton Foundation, Dr. Oliver Sabot, said the Board of Directors of Global Fund would be meeting in Addis Ababa, Ethiopia in about two weeks to decide which countries will benefit from cheaper malaria drugs" (Gathura/Esipisu, 11/2).

In related news, a study of some malaria markets found that "thousands of people die each year because they can't afford - or don't have access to - the most effective form of treatment, called artemisinin-based combination therapies or ACTs," Radio France Internationale reports (11/2).

According to Reuters, the study is part of the ACTwatch research project conducted by Population Services International (PSI) and the London School of Hygiene and Tropical Medicine. "ACTs can cost up to $11 to patients buying over the counter, while older drugs to less effective drugs cost just $0.30 cents. 'With most people accessing anti-malarial medication through the private sector, price becomes a critically important barrier,' said Desmond Chavasse, director of PSI. 'A full course of an adult treatment of ACT can be up to 65 times the minimum daily wage. This provides an overpowering incentive (for patients) to make the wrong anti-malarial choice,'" the news service writes.    

The study found that ACTs comprise between five and 15 percent of the total volume of malaria medicines on the market. Chavasse said ACT availability can be as low as 20 percent in public health clinics, even though most malaria-endemic countries have policies that encourage the use of ACTs (Kelland, 11/2).

In a PSI press release, Kara Hanson of the London School of Hygiene & Tropical Medicine, said, "The operation of the distribution chain has a major influence on which antimalarials are available to retailers, and their price and quality. ... Influencing practices of providers near the top of the chain may be the most cost-effective way to change outcomes in this market" (11/2).