Malaria killed more than 400,000 people in 2015 and infected more than 200 million. The parasite behind the disease is Plasmodium falciparum, pictured, which scientists are trying to develop an effective vaccine against.
Professor Adrian Hill and his team at the University of Oxford are creating a vaccine formula unlike any in use today, targeting a new arm of the human immune system. He hopes this new approach will one day help eliminate malaria.
The life cycle of the malaria parasite is complex and has many stages of development inside the human body. One stage is their transformation into 'merozoites' where they infect blood cells and replicate inside them, growing in number until the cells burst (pictured) releasing them into the bloodstream to infect more cells.
Hill (pictured) and his team are developing vaccines against four different stages of the parasite's life cycle to one day combine them into one vaccine bringing more potent protection.
Insecticide-treated bed nets (pictured) have been pivotal in bringing down malaria cases in recent years. But insecticide resistance is developing and likely to spread. With minimal new options to replace them, control efforts need a more sustainable option, such as a vaccine.
Hill's team at the Jenner Institute have been studying the parasite and the mosquito vectors that carry them for many years. Here, a team member is dissecting a mosquito under a microscope.
Insecticide spraying (pictured) has been another approach in malaria control in areas with seasonal malaria, where malaria cases rise rapidly during their rainy season. However, resistance is again making this option less effective than recent years.
Drug resistance has been a key player throughout the malaria epidemic and has resulted in the constant need for new treatments. The latest combination drug approach, based on artesunate, has saved millions of lives, but resistance has begun to emerge in Asia.
To understand more about the disease in humans, and to test the protective effect of vaccines, Hill's team expose willing volunteers to bites by mosquitoes infected with malaria. Here, a volunteer lays his arm on top of a cup containing mosquitoes.
Hill's vaccine showed 67% efficacy when trialed in adults in Kenya, but his target are infants. By immunizing them before they are six months of age, Hill believes the majority of malaria cases -- and deaths -- could be prevented. He hopes to reach clinical trials in infants by 2022 with further hope of licensing his vaccine by 2025.