Reports of chickenpox cases in the U.S. have declined sharply after a new vaccine was released in 1995, a new study confirms. According to a report from HealthDay News, hospitalizations and outpatient visits for the disease have dropped even further since 2006, when doctors began recommending a second dose of the vaccine.

Before the vaccine was made available throughout the country, chickenpox affected nearly 4 million people each year. 11,000 were hospitalized annually, and an average of 150 people died from the disease, according to statistics from the CDC.

Researchers analyzed national health insurance claims data to determine just how effective the vaccine was. They discovered that by 2012, hospitalizations had dropped 93 percent, and outpatient visits had dropped 84 percent compared to the time period before the vaccine was available.

When doctors began recommending a second dose of the varicella vaccine, hospitalizations dropped 38 percent and outpatient visits for chickenpox dropped 60 percent.

The authors of the study found significant decreases in chickenpox cases among children aged 1 to 19, the primary target group for vaccinations. Children younger than 1 year also saw a sharp decrease in chickenpox cases, though the vaccine is not recommended for this age group.

The vaccination has helped stem the spread of the disease, which is highly infectious and contagious. Typical symptoms of chickenpox include rashes, itching, fatigue, and fever.