Vaccines outlook Q&A more attention on tackling the mosquitoes that carry the disease and preventing trans- mission, rather than priming people to fight off the parasite. Hill thinks eradication of malaria is not possible with the tools currently available, and that new vaccines are ultimately Jeffrey Bethony: necessary. Duffy agrees: “An effort like elimi- nation means you have to bring lots of tools Taking on worms together,” he says. “A vaccine can be an impor- tant addition.” About two billion of the world’s poorest Haem is potentially toxic, and antibodies Vaccines could be useful in the battle to people are infected with parasitic worms. against the degradation protein reduce the prevent transmission, too. One way to stop Treatments are available, but Jeffrey worm’s ability to eliminate haem from its the parasite jumping between human and Bethony, a microbiologist at George blood meals. The other protein prevents hook- mosquito is to sabotage the parasite’s sexual Washington University in Washington DC, worms from breaking down haemoglobin for stage. Duffy’s team has developed a transmis- explains why only vaccines can eradicate consumption. We have done separate phase I sion-blocking vaccine that targets the sexual infection. trials of our two vaccines in the United States, forms that are taken up by mosquitoes when Brazil and Gabon, and have just received fund- they ingest human blood cells. In an initial Why is it more difficult to develop a vaccine ing to test both proteins using a controlled field trial of this type of vaccine, conducted...