“One of the questions has always been if you vaccinate, will you cause flares of the disease. This paper, along with other studies, all demonstrated that children with juvenile arthritis do not flare,” Dr. Lovell says. “This is another piece in the growing body of evidence to say that these vaccines do not flare the JIA.”

Other pediatric rheumatologists say that while the study is encouraging, they won’t yet recommend live vaccines.

“This study is relatively small. But I personally believe it’s probably right,” says Barbara Adams, MD, at the University of Michigan’s C.S. Mott Children’s Hospital in Ann Arbor.

But she says she needs more scientific proof than this new study provides.

“Professionally, we have to take another measure of precaution. And the reason is because there hasn’t been a big study,” she explains. “I think this is a pretty important thing to nail down one way or another, and I’d like to see someone do a more comprehensive study with a broader group of patients to give us the real answer.”

Before the vaccine was introduced in 1995, chickenpox was responsible for about 4 million infections, 100,000 hospitalizations and about 100 deaths in American children each year.

And though vaccination has cut the number of cases of chickenpox by more than 80 percent, the disease hasn’t disappeared completely, and ninety percent of cases are seen in children less than the age of 10.

A 2010 study published in the Archives of Pediatrics and Adolescent Medicine found that children who were not vaccinated for chickenpox had nine times the risk of infection compared to those who were immunized.

Still, because of safety concerns, pediatric rheumatologists advise parents of children with arthritis not to risk immunization with live viruses.

“We write letters [to schools] saying the child may not have the chickenpox vaccine because they are taking a medicine that makes them immunosuppressive,” Dr. Adams says. “The parents agree with us. They are asking us to write it.