The vaccine builds on what happens naturally in certain people--about 20% of the Japanese, Chinese, and Korean population--with an alcohol intolerance mutation. Normally, the liver breaks down alcohol into an enzyme thatís transformed into the compound acetaldehyde (responsible for that nasty hangover feeling), which in turn is degraded by another enzyme. The acetaldehyde doesnít usually have time to build up before itís broken down. But people with the alcohol intolerance mutation lack the ability to produce that second enzyme; acetaldehyde accumulates, and they feel terrible.
Asenjo and his colleagues have come up with a way to stop the synthesis of that second enzyme via a vaccine, mimicking the mutation that sometimes happens naturally. "People have this mutation all over the world. Itís like how some people canít drink milk," explains Asenjo.