VANGUARD® CIV vaccines have demonstrated efficacy by mitigating clinical signs of disease as well as viral shedding.
VANGUARD CIV H3N2/H3N8 Vaccine Demonstrated Against Heterologous CIV H3N2 Challenge5
In a controlled laboratory challenge, 40 dogs were exposed to CIV H3N2. Twenty dogs were vaccinated with VANGUARD CIV H3N2/H3N8 on study days 0 and 21, and 20 dogs were placebo vaccinated on the same days. Efficacy was measured by evaluation of lung lesions attributable to CIV H3N2 infection and by observation of disease.
Pathological lung lesions and disease*
0% of dogs vaccinated with VANGUARD CIV H3N2/H3N8 were impacted by disease and pathological lung lesions
85% of the control group were impacted by disease and pathological lung lesions
Microscopic lesions in lungs consistent with CIV H3N2 infection†
0% of dogs vaccinated with VANGUARD CIV H3N2/H3N8 had evidence of CIV H3N2 infection on a microscopic exam of lungs and trachea
100% of the control group had evidence of CIV H3N2 infection on a microscopic exam of lungs and trachea
Shedding of CIV H3N2 after challenge
Dogs in the control group shed CIV H3N2 for an average of 4.9 days after challenge. Dogs vaccinated with VANGUARD CIV H3N2/H3N8 shed virus for an average of 1.3 days after challenge.
Virus isolation from lung lavage and tissue after CIV H3N2 challenge
CIV H3N2 was not isolated from lung lavage fluid or tissues in any of the vaccinated dogs. Sixty percent of the control group had CIV H3N2 isolated from tissue and/or lavage fluid.
CIV H3N2 and H3N8 antibody titers by hemagglutination inhibition (HAI)
At the study start, all dogs were seronegative to both CIV strains.
Before CIV H3N2 challenge, antibody titers for both CIV H3N2 and CIV H3N8 were significantly increased (p<0.0001) in all vaccinates when compared to the controls, which had negative titers. All vaccinates had detectable titers to CIV H3N2 and CIV H3N8 by day 21 when the second vaccination was administered.
After the CIV H3N2 challenge, the control group maintained negative HAI titers for CIV H3N8.
*In order for a dog to be considered as diseased, two or more clinical signs of respiratory disease were required to be present on two or more consecutive days post-challenge. Observed clinical signs: fever, coughing, depression, excessive nasal discharge, increased respiratory noise, dyspnea, retching and sneezing.
†Observed lesions: alveolitis, bronchitis and/or epithelial alteration of bronchi, bronchioles and trachea (19/20 dogs).