A new study shows that the number of Chickenpox cases in the United States have dropped massively since 1995.

The study credits the introduction of a vaccine that first became available in that year, which researchers believe has resulted in a drop in hospitalizations and outpatients visits for chickenpox particularly since 2006, when a second dose of the vaccine was created to boost protection, according to a HealthDay News report.

About 4 million people in the United States came down with chickenpox each year back in 1995, requiring 11,000 hospitalizations that resulted in 150 deaths, based on figures from the U.S. Centers for Disease Control and Prevention.

CDC researchers used national health insurance claims data to base their findings, which indicated 93 percent fewer hospitalizations for chickenpox in 2012, and 84 percent less outpatient visits than the period before the vaccine had been introduced.

The second dose caused hospitalizations to decline by 38 percent and outpatient visits by 60 percent.

The varicella vaccine, as it is called, resulted in “significant declines” in rates of chickenpox after both the 1995 and 2006 events, with the largest decrease happening among children and teens who were aged 1 to 19, a group that is typically targeted for vaccination, said study co-author Jessica Leung, according to the report.

But even for children younger than 12 months there were drops in outpatient visits and hospitalizations, even though the vaccine isn’t recommended for them. It was also true for adults, even though adults typically don’t get vaccinated for the disease.

The findings were published in the Journal of the Pediatric Infectious Diseases Society.