This month, dr Ossama Motawae, an Egyptian veterinarian, published an interesting presentation on the use of inactivated H5N2 vaccine to reduce the H5N1 virus load and inhibit the further reemergence of H5N1 genotypes. His conclusion is that commercial inactivated oil-emulsion A/CK/Mexico/ 232/94 (H5N2) provides protection against challenge with low doses of A/CK/HK/86.3/02 (H5N1) virus but does not prevent virus shedding. When the severity of challenge was increased in the second experiment, 1 of 10 vaccinated birds died but not in the third experiment. However, virus shedding in vaccinates in the first experiment was sufficient to infect 50% of unvaccinated contact controls. Despite high levels of HI antibody, the heavily challenged birds were not fully protected, thus raising the question of lack of genetic similarity between the vaccine and challenge virus.

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