A team of National Institutes of Health researchers has concluded that the often-touted benefits of flu shots to people over the age of 70 are highly exaggerated - there is no real proof they provide protection to the frail elderly. The conclusion published Monday in an online edition of the British journal The Lancet Infectious Diseases is unwelcome news for public health officials in the United States who are preparing to launch the annual flu shot campaign. This season, the Centers for Disease Control and Prevention hopes that a record 132 million doses of flu vaccine will be manufactured for the U.S. market, but the federal agency has been having a hard time boosting the number of Americans who line up for the shots. Last year, at least 18 million doses of flu vaccine went to waste. The CDC's long-standing goal is to have 90 percent of seniors aged 65 and older vaccinated against flu. The policy has made progress: In the 2005-06 flu season, 69 percent of that population was vaccinated, compared to just 15 percent in 1980. It is precisely that success that has led disease control experts in recent years to question the value of the vaccine. With such a large increase in immunization rates, a drop in flu deaths among the elderly would have been expected. But several studies have failed to show any such reduction. The report underscores growing doubts about how useful the current flu vaccines are for the elderly.