Remember getting chickenpox as a kid? It wasn’t fun at all. But there’s excellent news if you don’t want your child to get it and the potential complications that come with it: scientists have found that a second dose of chickenpox vaccine, which combats the varicella-zoster virus, is incredibly effective.

Researchers at the Centers for Disease Control and Prevention say there has been an 85 percent drop in chickenpox between 2005-2006 and 2013-2014, and the drop was most pronounced in children from 5 years of age up to 14, which is also the group that is most likely to get a second dose of the vaccine.

Chickenpox is an unpleasant illness that results in an itchy rash covering the body, and fever and fatigue as well. But it’s not just uncomfortable: it can be downright dangerous for very young children, the elderly, and those with compromised immune systems.

The frequency of chickenpox has been dropped, from as many as 4 million Americans in the 1990s with 13,500 hospitalizations and 150 deaths, to 3.5 million cases with 9,000 hospitalizations and 100 deaths each year.

“People should not get chickenpox vaccine if they have ever had a life-threatening allergic reaction to a previous dose of chickenpox vaccine or to gelatin or the antibiotic neomycin,” the CDC says on its website. “People who are moderately or severely ill at the time the shot is scheduled should usually wait until they recover before getting chickenpox vaccine. Pregnant women should wait to get chickenpox vaccine until after they have given birth. Women should not get pregnant for 1 month after getting chickenpox vaccine.”