H5N1 Vaccine Could Be Vasis for Life-Saving Stockpile
H5N1 Bird Flu Vaccine
Scientists at St. Jude Children's Research Hospital have announced that a vaccine they developed a few years ago against one antigenic variant of the avian influenza virus H5N1 may protect humans against future variants of the virus. Vaccines based on this model might therefore be suitable for stockpiling for use during a pandemic (worldwide epidemic) until a new vaccine could be developed specifically against the variant causing the outbreak, the researchers said. An antigen is a molecule that stimulates production of antibodies by the immune system.
A prepublication report on the study appears in the online issue of Journal of Infectious Diseases (JID).
The researchers showed that the vaccine completely protected ferrets from a lethal nasal infection against not only the original virus the vaccine was made to thwart, but also against a newer variant that has already proved fatal to humans. The ferrets experienced a more significant reduction of virus multiplication than otherwise would have occurred, the researchers reported. Moreover, the infections failed to spread out of the upper respiratory tract to the lungs or brain.
"These findings are especially significant because ferrets are known to be an excellent and accurate model of influenza infection and immune response in humans," said Elena Govorkova, Ph.D., a staff scientist in the Department of Infectious Diseases at St. Jude. "Restricting the infection to the upper respiratory tract is important since in humans the virus has been isolated from specimens taken from the cerebrospinal fluid, feces, throat and blood serum. Therefore, limiting the spread of virus in an infected human is crucial to saving that person's life." Govorkova is the lead author of the JID paper and led the research team conducting the study.
The team also showed that the optimal strategy for vaccination of immunologically na