title: Efficacy of a modified live intranasal bovine respiratory syncytial virus vaccine in 3-week-old calves experimentally challenged with BRSV.
abstract: Two experimental bovine respiratory syncytial virus (BRSV) challenge studies were undertaken to evaluate the efficacy of a single intranasal dose of a bivalent modified live vaccine containing BRSV in 3-week-old calves. In the first study, vaccine efficacy was evaluated in colostrum deprived (maternal antibody negative) calves 5, 10 and 21 days after vaccination. Nasal shedding of BRSV was significantly reduced in vaccinated calves challenged 10 or 21 days after vaccination. Virus excretion titres were also reduced in vaccinates challenged 5 days after vaccination but reduction in duration of shedding and total amount of virus shed were not statistically significant. Clinical disease after challenge in this study was mild. In the second study, vaccine efficacy was assessed in calves with maternal antibodies against BRSV by challenge 66 days post-vaccination. Vaccination significantly reduced nasal shedding after challenge and the severity of clinical disease was also reduced.
authors.affiliation: Pfizer Animal Health, Veterinary Medicine Research and Development, Ramsgate Road, Sandwich, Kent CT13 9NJ, UK. ilse.vangeel@pfizer.com
authors.forename: Ilse
authors.initials: I
authors.lastname: Vangeel
authors.forename: Adriaan F G
authors.initials: AF
authors.lastname: Antonis
authors.forename: Manuela
authors.initials: M
authors.lastname: Fluess
authors.forename: Lutz
authors.initials: L
authors.lastname: Riegler
authors.forename: Andy R
authors.initials: AR
authors.lastname: Peters
authors.forename: Silke S
authors.initials: SS
authors.lastname: Harmeyer
mesh_terms: D000281:Administration, Intranasal; D000375:Aging; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000517:prevention & control*; D007958:Leukocyte Count; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D018112:Respiratory Syncytial Virus, Bovine / Q000276:immunology*; D013997:Time Factors; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014766:Viremia / Q000276:immunology / Q000821:virology; D017201:Virus Shedding
chemical_list: D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines