Is there a vaccine to prevent pandemic influenza?
• Vaccine is the first line of defense to protect people from getting the flu. • There are no commercial supplies of vaccine against pandemic influenza virus because the specific pandemic strain is not known in advance. • It is impossible to develop a perfect match vaccine until a new influenza virus has shifted to human-to-human transmission and that strain has been identified and characterized so that a vaccine can be developed. • The United States and other countries are developing and producing supplies of human vaccines for the current H5N1 strain of avian influenza, but there is no guarantee that these will be effective against a new human-to-human influenza strain. • Influenza vaccine production depends largely on chick embryos. A virulent avian influenza strain may be lethal for chick embryos and make current vaccine production methods ineffective.
