New flu vaccine cuts adverse reactions.

A new, genetically engineered influenza vaccine under study at Saint Louis University School of Medicine may offer protection from the flu with fewer of the minor side effects associated with licensed vaccines currently in use. Participants who received the new vaccine had significantly lower rates of influenza infection and illness during the winter flu season than did those who received a placebo that did not contain flu vaccine. In addition, those receiving the new vaccine had fewer local reactions such as arm pain or tenderness than those inoculated with a licensed influenza vaccine.

Currently licensed influenza vaccines are made by growing the virus in chicken eggs, then killing and purifying it for use in the vaccine. The new vaccine is made by a genetic engineering process that allows scientists to create a copy of one protein on the surface of the influenza A virus. Immunity against that surface protein, known as hemagglutinin, is believed to be key to protection against infection. None of the actual virus is included in the new vaccine. Instead of being grown in eggs as the licensed vaccines are, it is produced in cells derived from moths.

"It appears that this highly purified vaccine, free of egg...