Resistance to the anti-viral drug ganciclovir may be more likely in cystic fibrosis patients after a lung transplantation.

A Loyola University Medical Center study found that such resistance may occur more frequently in cystic fibrosis patients. These patients were found to have insufficient levels of the drug in their bloodstream, enabling the virus to continually replicate. This in turn may increase the chance that mutations will occur and result in drug resistance.