Curing disease is really a matter of outfoxing evolution. When we assault bacteria or viruses or cancer cells with drugs, they evolve ways of resisting those drugs. We attack, they counter-attack. Take malaria: the Plasmodium parasites that cause the disease have repeatedly evolved to resist our best anti-malarial drugs. The mosquitoes that carry the parasites have evolved to resist the insecticides we poison them with. And now, Victoria Barclay from Pennsylvania State University has found that some malaria vaccines could drive Plasmodium to become even deadlier than it is now.
Several malaria vaccines are in development, but none have been licensed yet. Barclay vaccinated mice with a protein that’s found in several of these vaccines, and then exposed them to Plasmodium. After a few generations, the parasite became more ‘virulent’ – that is, it caused more severe disease. And it did so via an evolutionary escape route that is rarely considered.
Vaccine creators aren’t naive to the possibility of resistance. They’re trying to train the immune system to recognise and destroy Plasmodium by presenting them with proteins on the parasite’s surface, and they know that the parasites could …
from Discover Magazine
