Mads Bertelsen, Carsten Grøndahl, Elisabeth Holm (DFVF), Joan Klausen (DFVF), Poul Jørgensen (DFVF).

540 birds in three zoos were vaccinated twice against avian influenza with a 6 week interval using an inactivated H5N9 vaccine. Serological response was evaluated by hemagglutination inhibition test 4-6 weeks following the second vaccine administration. 84% of the birds seroconverted, and 76% developed a titre ≥ 32. The geometric mean titre after vaccination was 137. A significant species variation in response was noted; penguins, pelicans, ducks, geese, herons, Guinea fowl, cranes, cockatiels, lovebirds, and barbets showed very poor response to vaccination, while very high titres and seroconversion rates were seen in flamingos, ibis, rheas, Congo peafowl, Black-winged stilts, amazon parrots, and kookaburras.