In the US, many businesses offer flu vaccines to their employees, and people make doctor's appointments or stand in long lines at pharmacies to get their shot each year. But the massive -- and expensive -- effort may be for nought, suggests new research.

Dr. Tom Jefferson of the Cochrane Collaboration in Rome said that results of his study, which is published in the British Medical Journal, suggest Americans and Europeans may be wasting their time and money on the annual exercise.

Roughly 200,000 people in the US are stricken with flu cases so severe they require hospitalization, and 36,000 die as a result of the infection, according to figures from the Centers for Disease Control and Prevention.

Because influenza viruses mutate from one year to the next, the vaccine offered does not precisely match the type of flu bug that may be circulating in a given season.

There is little evidence that getting a flu shot, whether one is healthy or at high risk, makes any significant difference, Dr. Jefferson's research suggests.

Dr. Jefferson saw no significant decline in duration of hospitalization, days lost from work or rate of death among adults who were vaccinated.

There was no difference in outcome between children under two who received a flu vaccine and those who received a placebo.

Dr. Jefferson's study was an analysis of the reviews of all published studies worldwide on the effects of vaccines that used dead flu viruses.

He called for an urgent reevaluation of current flu vaccine policies.