More than 2,000 students at the University of Michigan are helping to figure out whether wearing surgical masks and using hand sanitizer actually helps to prevent the spread of the flu.

The university started handing out the hygienic tools this week to students in residence as part of an experiment to test if the low-tech measures offer protection from the influenza virus.

The experiment comes as health experts watch for any signs that the H5N1 form of avian flu is mutating into a form that can spread easily between people, a change that could spark a pandemic.

Unlike bacteria, viruses such as the flu do not respond to antibiotics. Antivirals exist but the supply is limited, and vaccines would take time to produce during a pandemic.

"There is some anecdotal evidence from prior pandemic outbreaks that masks may have helped, but no firm data," said study leader Arnold Monto, a professor of epidemiology at the University of Michigan's school of public health.

Students living in different dormitories will be assigned to use masks only, both masks and sanitizer, or neither. Use of hand sanitizer and masks will begin when a confirmed case of flu is found in a campus dorm, the researchers said.

Study participants will be expected to wear the masks at all times in the dorm but it's optional elsewhere. Those participating in the experiment will receive up to $100 US, with those who get sick and have their throats swabbed receiving the most.

They will also receive stickers and magnets that list flu symptoms and include a pager number for students to report suspected cases of the flu. A nurse will then go to the dorm to collect samples.

The H5N1 flu continues to be mainly a disease of birds, although 270 people have been infected since 2003 and 164 have died, according to the World Health Organization.

The study is funded by the U.S. Centers for Disease Control and is timed to coincide with the start of flu season in the U.S.