On Feb. 25, 2002, GlaxoSmithKline announced that the company would no longer manufacture or distribute its Lyme disease vaccine, LYMErix, because sales of the vaccine had declined from about 1.5 million doses in 1999 to a projected 10,000 doses in 2002.

Lyme disease, or borreliosis, is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of an infected blacklegged deer tick. It is the most common tickborne infectious disease in the United States.