The WHO’s response caused widespread, unnecessary fear and prompted countries to waste millions of dollars, according to one report. At the same time, the Geneva-based arm of the United Nations relied on advice from experts with ties to drug makers in developing the guidelines it used to encourage countries to stockpile millions of doses of antiviral medication, according to the second report.

A spokesman for the WHO and several independent experts strongly disputed the reports, saying they misrepresented the seriousness of the pandemic and the agency’s response, which was carefully formulated and necessary, given the potential threat.

“The idea that we declared a pandemic when there wasn’t a pandemic is both historically inaccurate and downright irresponsible,” WHO spokesman Gregory Hartl said in a telephone interview. “There is no doubt that this was a pandemic. To insinuate that this was not a pandemic is very disrespectful to the people who died from it.”

The first report, released in Paris, came from the Social, Health and Family Affairs Committee of the Parliamentary Assembly of the Council of Europe, which launched an investigation in response to allegations that the WHO’s reaction to the swine flu pandemic was influenced by drug companies that make antiviral drugs and vaccines.

The second report, a joint investigation by the BMJ, a prominent British medical journal, and the London-based Bureau of Investigative Journalism, criticized the WHO’s 2004 guidelines, which were developed based in part on the advice of three experts who received consulting fees from the two leading manufacturers of antiviral drugs used against the virus, Roche and GlaxoSmithKline.

Hartl dismissed those charges.

“We know that some experts that come to our committees have contact with industry. It would be surprising if they didn’t because the best experts are sought by all organizations,” Hartl said. “We feel that the guidelines produced were certainly not subject to undue influence.”