Written Into Our Genes

Malaria's pressure on humanity was so relentless that evolution struck a brutal bargain. The sickle cell gene is the proof.

Inherit two copies and you get sickle cell disease, which can be deadly. But inherit just one copy and it protects you against malaria. That single benefit was so valuable that the gene spread widely in malaria regions, even though it harms the unlucky few who inherit both copies.

Locked in an Arms Race

All those defenses are why fighting malaria has been so hard for medicine, not just for the immune system. For decades, vaccine after vaccine failed, because the parasite that dodges your antibodies also slips past the targets a shot is built to hit.

The first approved malaria vaccine arrived only recently, and even it is only partly protective, needing several doses. Worse, surviving malaria barely builds lasting immunity, so people in the hardest-hit regions can be reinfected again and again. We aren't just fighting a germ. We're fighting an opponent that has been evolving to beat the human body for as long as there have been humans.