Scientist falsified Aids vaccine study, American court told

A South Korea-born scientist has pleaded not guilty to charges alleging that he falsified research for an Aids vaccine to secure millions of dollars in US federal funding.

Dong-pyou Han, 57, entered pleas to four counts of making false statements during his initial court appearance in Des Moines federal court. Each count carries a maximum sentence of five years' jail and a US$250,000 fine.

The former Iowa State University scientist was released on bond and his trial was scheduled for September 2.

Prosecutors say Han wrote a letter to university officials before he resigned last fall in which he confessed that he had spiked samples of rabbit blood with human antibodies to make an experimental HIV vaccine appear to have great promise. Han told them he started the fraud in 2009 "because he wanted [results] to look better" and that he acted alone. "I was foolish, coward, and not frank," he wrote.

Han's actions raised hopes of a vaccine breakthrough, but the alleged misconduct was uncovered last year after scientists at Harvard University discovered the spiked samples.

According to the indictment, Han's misconduct caused colleagues to make false statements in a federal grant application and progress reports to National Institutes of Health (NIH).