For the first time in years, Douglas County health officials are tracking cases of chickenpox, also known as varicella.

And in 2004, there were four confirmed and 18 probable cases, according to Kim Ens, disease control program coordinator for the Lawrence-Douglas County Health Department.

Ens said the health department was tracking cases and reporting them to the Kansas Department of Health and Environment.

“It’s mainly being done so that we can do some follow-up on how effective the vaccine is,” Ens said.

Kansas now requires all children entering kindergarten to be vaccinated for chickenpox, an acute, contagious viral disease. While the vaccine isn’t 100 percent effective, Ens said, area health officials have noticed a difference in how chickenpox affects children who have been vaccinated.

“Even though some kids who have been vaccinated still get chickenpox, we know the vaccine is cutting down on the severity of it,” Ens said. “So we know it’s helping a lot.”

It also has been reported that the vaccine contributed to the decline in the number of chickenpox cases. Deaths caused or related to chickenpox have dropped to the lowest level ever after the vaccine was introduced in 1995.

Five years before the vaccine was introduced, chickenpox caused or contributed to an average of 145 deaths each year nationally. The number of U.S. deaths dropped to 66 in a matter of years once the vaccine was on the market, researchers at the U.S. Centers for Disease Control and Prevention reported in the New England Journal of Medicine.

Ens said the Lawrence-Douglas County Health Department began reporting cases in August 2004 to the Kansas Department of Health and Environment. She said doctors and school nurses periodically called in reports of chickenpox to health department officials.

KDHE spokeswoman Sharon Watson said there were 258 confirmed cases and 349 probable cases of chickenpox in the state in 2004.

— Journal-World wire services contributed to this report.