Lyme disease is an illness caused by bacteria most commonly spread to humans from ticks. It can cause arthritis, muscle weakness and pain.

Lyme disease is an illness caused by bacteria most commonly spread to humans from ticks. It can cause arthritis, muscle weakness and pain.

The vaccine demonstrated a reduction in the rate of infections, but fell short of a key statistical requirement.

The first human Lyme disease vaccine was 73% effective against the tick-borne illness, says Pfizer. They still plan to seek approval.