Field effectiveness of highly pathogenic avian influenza H5N1 vaccination in commercial layers in Indonesia

• Published in: PloS one Vol. 13; no. 1; p. e0190947
• Main Authors: Tarigan, Simson, Wibowo, Michael Haryadi, Indriani, Risa, Sumarningsih, Sumarningsih, Artanto, Sidna, Idris, Syafrison, Durr, Peter A, Asmara, Widya, Ebrahimie, Esmaeil, Stevenson, Mark A, Ignjatovic, Jagoda
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10-01-2018; Public Library of Science (PLoS)
• Subjects: Animal Husbandry; Animals; Antibodies; Antibodies, Viral - blood; Antigenic variants; Antigens; Avian flu; Avian influenza; Biology and Life Sciences; Birds; Care and treatment; Chickens - immunology; Chickens - virology; Dosage and administration; Epidemics; Hemagglutination inhibition; Hemagglutination Inhibition Tests; Immunity; Indonesia; Influenza; Influenza A Virus, H5N1 Subtype - immunology; Influenza in Birds - immunology; Influenza in Birds - prevention & control; Influenza in Birds - virology; Influenza vaccines; Influenza Vaccines - administration & dosage; Influenza viruses; Longitudinal Studies; Medicine and Health Sciences; Pandemics; People and Places; Poultry; Poultry Diseases - immunology; Poultry Diseases - prevention & control; Poultry Diseases - virology; Prevention; Prospective Studies; Treatment Failure; Vaccination; Vaccines; Viruses; Indonesia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0190947

Although vaccination of poultry for control of highly pathogenic avian influenza virus (HPAIV) H5N1 has been practiced during the last decade in several countries, its effectiveness under field conditions remains largely unquantified. Effective HPAI vaccination is however essential in preventing incursions, silent infections and generation of new H5N1 antigenic variants. The objective of this study was to asses the level and duration of vaccine induced immunity in commercial layers in Indonesia. Titres of H5N1 haemagglutination inhibition (HI) antibodies were followed in individual birds from sixteen flocks, age 18-68 week old (wo). The study revealed that H5N1 vaccination had highly variable outcome, including vaccination failures, and was largely ineffective in providing long lasting protective immunity. Flocks were vaccinated with seven different vaccines, administer at various times that could be grouped into three regimes: In regime A, flocks (n = 8) were vaccinated two or three times before 19 wo; in regime B (n = 2), two times before and once after 19 wo; and in regime C (n = 6) three to four times before and two to three times after 19 wo. HI titres in regime C birds were significantly higher during the entire observation period in comparison to titres of regime A or B birds, which also differed significantly from each other. The HI titres of individual birds in each flock differed significantly from birds in other flocks, indicating that the effectiveness of field vaccination was highly variable and farm related. Protective HI titres of >4log2, were present in the majority of flocks at 18 wo, declined thereafter at variable rate and only two regime C flocks had protective HI titres at 68 wo. Laboratory challenge with HPAIV H5N1 of birds from regime A and C flocks confirmed that protective immunity differed significantly between flocks vaccinated by these two regimes. The study revealed that effectiveness of the currently applied H5N1 vaccination could be improved and measures to achieve this are discussed.