Flu vaccines have traditionally contained egg proteins. These can trigger a rare, but potentially fatal allergic reaction in some people. Now, Austrian researchers say they're working on an egg-free flu vaccine.

Dr. Otfried Kistner, head of the project, described the vaccine Monday at a meeting of the American Chemical Society.

He says his team has developed a new technique for production that is actually faster than methods requiring chicken eggs.

Though at least two other manufacturers are testing egg-free flu vaccines, Kistner says only his company is using cells approved in the U.S. and Europe for use in human vaccine production.

Clinical trials were conducted in the United Kingdom, Austria and Poland. The studies showed the new vaccine induced specific antibodies against influenza, an indication it will protect against infection.

Among the older patients who received the new vaccine, significantly fewer adverse effects were observed compared to those who received conventional vaccines. In the younger group, no significant differences in adverse effects were observed. Adverse effects were typically mild, including reddening of the skin and swelling.

Nothing wrong with other vaccines

Kistner says their egg-free version of the vaccine doesn't mean conventional vaccines are bad. He says the benefits of vaccination greatly outweigh the risk of an allergic reaction.

He says the point of their vaccine is to improve on a good thing, and to minimize risk.

The vaccine is expected to be available to consumers in Europe next year.

Influenza is a respiratory infection that is potentially fatal. At greatest risk are infants, the elderly and people with certain chronic conditions such as diabetes.

The virus in a flu vaccine is chemically inactivated, but its presence stimulates the body to generate antibodies to fight off invading influenza strains.