Think that chickenpox is no big deal and just a typical childhood ailment? Think again. In reality, thousands of people get hospitalized with the disease every year, and it can result in painful complications down the road — which is why it’s such good news that a recent study from the Centers for Disease Control and Prevention finding that a second dose of a vaccine that combats the varicella-zoster virus that causes chickenpox is effective in treating the illness.

Chickenpox is nasty little disease that many of us get when we are children. We get covered in itchy, red spots, as well as perhaps a fever and some fatigue, and then it goes away, never to be seen again. But for many people, that’s not the case at all.

The reality is that each year, chickenpox kills 100 people in the United States, and forces another 9,000 hospitalizations. While the disease tends to be most dangerous for very young children, the elderly and those with compromised immune systems, even healthy adults can experience big problems from chickenpox.

Chickenpox can result in complications like bacterial infections, pneumonia or inflammation of the brain, and the varicella zoster virus also can result in a painful condition called shingles later on in life.

But the CDC report provides good news: cases of chickenpox have dropped from 4 million annually in the 1990s to 3.5 million today. And if this study is any indication, a second dose of the vaccine could drive those numbers down even further.