Comparative Effectiveness of Two Oil Adjuvant-Inactivated Avian Influenza H9N2 Vaccines

• Published in: Avian diseases Vol. 60; no. 1 Suppl; p. 226
• Main Authors: Kilany, Walid H, Bazid, Abdel-Hamid I, Ali, Ahmed, El-Deeb, Ayman H, El-Abideen, Mohamed A Zain, Sayed, Magdy El, El-Kady, Magdy F
• Format: Journal Article
• Language: English
• Published: United States 01.05.2016
• Subjects: Adjuvants, Immunologic - administration & dosage; Adjuvants, Immunologic - chemistry; Animals; Chickens; Drug Compounding; Influenza A Virus, H9N2 Subtype - genetics; Influenza A Virus, H9N2 Subtype - immunology; Influenza in Birds - immunology; Influenza in Birds - prevention & control; Influenza in Birds - virology; Influenza Vaccines - administration & dosage; Influenza Vaccines - chemistry; Influenza Vaccines - genetics; Influenza Vaccines - immunology; Poultry Diseases - immunology; Poultry Diseases - prevention & control; Poultry Diseases - virology; Vaccination; Vaccines, Inactivated - administration & dosage; Vaccines, Inactivated - chemistry; Vaccines, Inactivated - genetics; Vaccines, Inactivated - immunology; LPAI H9N2; inactivated vaccine; SPF chickens; AIV
• DOI: 10.1637/11145-050815-Reg

Low pathogenic avian influenza H9N2 virus infection has been an important risk to the Egyptian poultry industry since 2011. Economic losses have occurred from early infection and co-infection with other pathogens. Therefore, H9N2 vaccination of broiler chicks as young as 7 days old was recommended. The current inactivated H9N2 vaccines (0.5 ml/bird) administered at a reduced dose (0.25 ml/bird) do not guarantee the delivery of an effective dose for broilers. In this study, the efficacy of the reduced-dose volume (0.3 ml/bird), compared with the regular vaccine dose (0.5 ml/bird) of inactivated H9N2 vaccines using two different commercially available adjuvants, was investigated. The vaccines were prepared from the local H9N2 virus (Ck/EG/114940v/NLQP/11) using the same antigen content: 300 hemagglutinating units. Postvaccination (PV) immune response was monitored using the hemagglutination inhibition test. At 4 wk PV, both vaccinated groups were challenged using the homologous H9N2 strain at a 50% egg infective dose (EID50) of 10(6) EID50/bird via the intranasal route. Clinical signs, mortality, and virus shedding in oropharyngeal swabs were monitored at 2, 4, 6, and 10 days postchallenge (DPC). The reduced-dose volume of vaccine induced a significantly faster and higher immune response than the regular volume of vaccine at 2 and 3 wk PV. No significant difference in virus shedding between the two vaccine formulas was found (P ≥ 0.05), and both vaccines were able to stop virus shedding by 6 DPC. The reduced-dose volume of vaccine using a suitable oil adjuvant and proper antigen content can be used effectively for early immunization of broiler chicks.