New approach to take on seasonal malaria deaths

Malaria remains a major cause of death in Kenya despite the many interventions the Health ministry has rolled out to address it.

The malaria hotspots — where the transmission of the disease is stable and occurs all year round — are in western Kenya, Nyanza and the coast.

In these areas, it is important to adhere to malaria control interventions at all times. They include sleeping under insecticide-treated bed nets, clearing bushes around the home, draining stagnant water in the environment, indoor residual spraying as well as prompt diagnosis and treatment for those infected.

Since malaria can affect all people, those at risk of its detrimental impact are usually children below five years old due to their low immunity and pregnant women.

As children grow older, in these areas with stable malaria transmission, they usually develop immunity against it.

So, even if they get infected in the future, they may just have mild symptoms or none at all. In short, people living in these areas could have malaria parasites in their blood without even knowing it, as they will not feel sick.

But this is not the case in parts of the country where malaria transmission is seasonal.

These include the Western Highlands of Kenya such as Kericho, Nandi, Eldama Ravine, Bomet, Uasin Gishu, Nyamira, Kisii and Trans Mara as well as in the arid and semi-arid areas — Northern Baringo, Turkana, parts of West Pokot, Marsabit, Mandera, Wajir, Garissa and Tana River — when environmental conditions favour the breeding of malaria parasites — temperatures of 18˚C or more and presence of stagnant or standing water.

In the Western Highlands, malaria transmission and infection happen during the long rain seasons that are also characterised by high temperatures.

For the arid and semi-arid areas, which experience high temperatures throughout the year, malaria transmission is usually limited to the rainy season when stagnant water on the ground encourages the breeding of mosquitoes.

In these regions with seasonal malaria, people are exposed to malaria parasites for short periods, thereby denying their bodies the ability to develop natural immunity against it from childhood to adulthood.

As such, the whole population is usually vulnerable to the adverse effects of the disease during the high-risk seasons, with the most affected being children. And this can lead to epidemics with case fatality rates of up to 10 times higher than what is experienced in areas where malaria transmission occurs regularly.

In Kenya, during these high-risk seasons, people are usually encouraged to adhere to malaria prevention measures such as sleeping under bed nets and draining stagnant water.

But these interventions are not ‘foolproof’ and malaria infection still occurs in these areas, putting the lives of many young children at risk.

To address this challenge, health experts recommend the use of malaria prevention drugs in combination with the new malaria vaccine (RTSS,S/ASO1E) before the malaria transmission seasons begin.

A new study published in the New England Journal of Medicine indicates that this new combination approach has the potential to prevent malaria in large parts of Africa where cases remain high and where the disease is transmitted seasonally.

“These results also offer important evidence for decision-makers on the use of malaria vaccines,” they state.

The London School of Hygiene and Tropical Medicine Researchers coordinated the study in collaboration with the Research Institute of Health Sciences based in Burkina Faso, as well as the University of Sciences, Techniques and Technologies of Bamako in Mali.

During the study, the researchers followed nearly 6,000 children aged between five and 17 months in Burkina Faso and Mali. The two countries are among those with a very high burden of malaria in Africa, just like Kenya.

The results — at the end of three years — revealed that seasonal administration of malaria prevention drugs in combination with the vaccine reduced cases of uncomplicated malaria, admissions caused by severe cases as well as deaths by about 70 percent compared to the use of seasonal malaria prevention drugs alone, which was the custom in those two countries.

Seasonal vaccination with RTS,S/AS01E was also found to be as effective as four annual courses of malaria prevention drugs in protecting against uncomplicated malaria.

“The results of the trial were much more successful than we had anticipated. Our work has shown a combination approach using a malaria vaccine seasonally — similar to how countries use the influenza vaccine — has the potential to save millions of young lives. Importantly, we didn’t observe any new concerning pattern of side effects,” stated Dr Daniel Chandramohan, professor of public health from the London School of Hygiene and Tropical Medicine who was a member of the research team.

He added that further research is now needed to examine how seasonal malaria vaccination could be delivered most effectively at scale, in the areas where seasonal malaria transmission occurs.

Dr Brian Greenwood, another author of the study and professor of clinical tropical medicine at the London School of Hygiene and Tropical Medicine says the study results were very striking and could pave the way for a potential new approach to malaria control.

“The world has made great strides in tackling malaria but the pace of progress has slowed considerably in recent years. We urgently need new interventions, where the burden of malaria remains very high,” he said.

While the drugs used for malaria prevention remain effective, the researchers say if resistance to them increases without available alternatives, seasonal administration of malaria could be a potential solution.

“I am really proud of the contribution of our African research teams to these fantastic results. I hope that this evidence will be taken into account by decision-makers as a new additional strategy for saving children’s lives in Africa,” said Dr Jean-Bosco Ouedraogo, professor of parasitology at the IRSS based in Burkina Faso, who was also part of the research team.