Combatting Avian Flu

Researchers have constructed a vaccine that confers 100% protection to mice and chickens against the H5N1 virus, according to a Science A GoGo article. 100% effective, that is, against lethality, not infection per se. The control group was given an unmodified adenovirus vector based vaccine, and suffered the usual high mortality rates on exposure to H5N1. The experimental vaccine used a live adenovirus genetically engineered to express hemagglutin, a characteristic feature of H5N1 viral strains. They actually constructed several different versions with partial expression of traits and tested those.

The researchers speculate that because the vaccine contains a live virus, it may be more immune-activating than avian flu vaccines prepared by traditional methods. "The ability of this particular recombinant vaccine to induce both antibody and T cell directed immunity is extremely encouraging," said co-researcher Simon Barratt-Boyes. "This means that this recombinant vaccine can stimulate several lines of defense against the H5N1 virus, giving it greater therapeutic value. More importantly, it suggests that even if H5N1 mutates, the vaccine is still likely to be effective against it. How effective, we are not sure. We won't know until that occurs," he added.