A study suggests that the chickenpox vaccine, which contains a live virus, may be safe and effective for kids with juvenile arthritis.

Adults and children with arthritis who take medications that suppress the immune system have long been warned against taking any live vaccines. That’s because live vaccines contain a virus that has been weakened but is still active. Immunologists have feared that introducing this virus into a body with knocked-down defenses could result in serious illness or even death.

That’s left parents to wrestle with a potentially high stakes question: Is it riskier for children with juvenile arthritis who are also on immunosuppressive therapies to take the live vaccine or to get full-blown chickenpox?

But the new study, from researchers in Brazil, suggests that children with juvenile arthritis who are on disease-modifying medications, like methotrexate, and corticosteroids, like prednisone, can safely take the shots.

“I thought the study was very well done and challenges a paradigm, which is we’ve always said to not give live virus vaccines to juvenile arthritis patients on methotrexate or biologics. That’s been the party line. But this study challenges that party line,” says Daniel J. Lovell, MD, who works in the Division of Rheumatology at Cincinnati Children's Hospital Medical Center and is associate editor of Arthritis Care & Research.

“You do need a much longer, larger study to be thoroughly convinced that it’s the right thing to do, but it’s a brave study and scientifically well done,” he adds.

For the study, researchers gave the live varicella vaccine to 25 children with juvenile idopathic arthritis, or JIA, who had no antibodies to chickenpox. The participants were taking two immunosuppressive medications - methotrexate and corticosteroids. Four to six weeks after the shot, 72.2 percent of the participants appeared to be protected from chickenpox. One year later, 80 percent still had immunity.

“It doesn’t work 100 percent in a healthy population either, but it is higher than 70 or 80 percent,” Dr. Lovell says. “So the frequency of effectiveness of the vaccination was lower in this group (compared to healthy children)."

Three children did develop a mild chickenpox like rash that lasted up to a week and then went away, but there were no serious side effects in any of the children.

The study was published in Arthritis Care & Research, and it follows a 2007 study from the Netherlands, which found no infections or arthritis flares in 314 children with juvenile arthritis who were given the live vaccine against measles.

“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.