EFFICACY OF INACTIVATED H5N2 INFLUENZA VACCINES AGAINST LETHAL A CHICKEN/QUERETARO/19/95 INFECTION/

The control and eventual eradication of H5N2 influenza virus from dome stic poultry in Mexico is dependent on the use of avian influenza (AI) vaccine strategies. This study was performed to determine the amount of hemagglutinin (PIA) antigen required to control the signs of diseas e from a highly pathogenic H5N2 influenza virus (A/Chicken/Queretaro/1 9/95) and the amount of antigen required to prevent shedding of virus from vaccinated birds. Six commercial inactivated water in oil H5N2 va ccines available in Mexico were compared with standardized vaccines to assess their efficacy. The amount of HA required to prevent the signs of disease from A/Chicken/Queretaro/19/95 influenza virus was approxi mately 0.4 mu g per dose. Each of the six commercially available vacci nes prevented disease signs, and half of the vaccines significantly re duced viral shedding from vaccinated birds. There is a need for standa rdization of AI virus vaccine, and the antigen content should be incre ased in some of the commercially available AI vaccines in Mexico.