Long-awaited Lyme vaccine test begins

Researchers are seeking thousands of volunteers in the U.S. and Europe to test the first potential vaccine against Lyme disease in 20 years .

Lyme is a growing threat, with cases steadily rising and warming weather helping ticks expand their habitat. Now Pfizer and French biotech Valneva are aiming to avoids the pitfalls of their predecessor in developing a new vaccine to protect both adults and kids as young as 5 from the most common Lyme strains on two continents. Lyme disease historically has been undercounted and while the exact toll isn't clear, the U.S. Centers for Disease Control and Prevention cites insurance records suggesting a staggering 476,000 people are treated for the illness each year. The infection initially causes fatigue, fever and joint pain, and often -- but not always -- the first sign is a round, red rash that resembles a bull's-eye. Untreated Lyme can cause severe arthritis and damage the heart and nervous system. And for unknown reasons, some people have lingering symptoms even after treatment.