Sept. 17 (HealthDay News) -- A longer period of preventive treatment after kidney transplant can help reduce the risk that the patient will become infected with a virus that can cause devastating problems, new research suggests.

Healthy people can usually fight off the virus, called cytomegalovirus, but those with kidney transplants have weakened immune systems and are more susceptible to infection, the authors of the study noted in a news release from the American Society of Nephrology.

In the comparison study, Dr. Fu Luan, of the University of Michigan in Ann Arbor, and colleagues gave kidney transplant patients either three months or six months of treatment with the antiviral drug valganciclovir. They found that those who were given the longer treatment had a rate of infection that was half that of those who received treatment for three months (12 percent vs. 24 percent).

When the researchers took into account other factors that could have played a role, they found that the longer treatment regimen lowered the risk of cytomegalovirus by nearly two-thirds.

The study also found that the longer treatment is cost-effective, although it is expensive. But the study authors contend that it's cheaper in the long run to prevent infections that could end up being very costly.

The findings appear online Sept. 17 in the Journal of the American Society of Nephrology.

SOURCE: American Society of Nephrology, news release, Sept. 17, 2009