Vical (NASDAQ:[[ticker:VICL]]) says early results from a mid-stage trial of its cytomegalovirus vaccine look promising. The San Diego-based company says that at four months, 30 percent of treated patients had infections compared to 50 percent in the untreated group. Viral load measurements and other data all favor the vaccinated group, according to Vical, which did not provide a statistical analysis of the results. Although complete results from the study are due in early 2010, Vical says it is encouraged enough to plan its late-stage trial of the vaccine and talk with potential development partners. But investors seem unimpressed. Vical shares dipped 23 cents, or almost 9 percent, to $2.44 in afternoon trading.