Antibody response to feline herpesvirus-1 vaccination in healthy adult cats

Abstract

Objectives Vaccination against feline herpesvirus-1 (FHV-1) is recommended for all cats. However, it is unknown how adult healthy cats with different pre-vaccination antibodies respond to FHV-1 vaccination in the field. The aim of the study was to determine the prevalence of neutralising antibodies against FHV-1 in healthy adult cats and the response to FHV-1 vaccination within 28 days of vaccination. Methods One hundred and ten cats (⩾1 year of age) that had not received a vaccination within the past 12 months were vaccinated with a combined FHV-1 vaccine. Antibodies against FHV-1 were determined before vaccination (day 0), on day 7 and day 28 by serum neutralisation test. Uni- and multivariate statistical analyses were used to determine factors associated with the presence of pre-vaccination antibodies and response to vaccination. Results Pre-vaccination neutralising antibody titres (⩾10) were present in 40.9% of cats (45/110; 95% confidence interval [CI] 32.2–50.3); titres were generally low (range 10–640). Antibody response to vaccination (⩾four-fold titre increase) was observed in 8.3% (9/109; 95% CI 4.2–15.1). Cats ⩾2 years of age were more likely to have pre-vaccination neutralising antibodies than cats aged between 1 and 2 years (odds ratio [OR] 24.619; P = 0.005). Cats from breeders were more likely to have pre-vaccination neutralising antibodies than privately owned cats (OR 7.070; P = 0.007). Domestic shorthair cats were more likely to have an at least four-fold titre increase vs purebred cats (OR 11.22; P = 0.027). Conclusions and relevance Many cats have no detectable neutralising antibodies against FHV-1 despite previous vaccinations and fail to develop a ⩾four-fold titre increase after vaccination. This is likely because older cats and cats with a higher FHV-1 exposure risk are more likely to get infected with FHV-1 and thus to have FHV-1 neutralizing antibodies. Purebred cats more often fail to develop a ⩾four-fold titre increase after vaccination.

Immunogenicity of a new inactivated vaccine against feline panleukopenia virus, calicivirus, and herpesvirus-1 for cats

“…By contrast, vaccinated cats had a relatively low VNA titer of 3.2 against FHV-1. Many cats vaccinated with the con-ventional FHV-1 vaccine failed to show a more than fourfold increase in VNA titer [27]. VNA titer may be influenced by the dose and frequency of vaccination.…”

Pathogenicity and immunogenicity of gI/gE/TK-gene-deleted Felid herpesvirus 1 variants in cats

“…However, the cellular immune response can only be measured with sophisticated laboratory methods [ 44 , 45 ]. It has been shown that serum antibody testing is not useful in predicting the protection conferred against FHV infection [ 46 ] because FHV-1 vaccines act by inducing neutralizing antibodies and cellular immunity [ 47 , 48 ].…”

First Report of Isolation and Molecular Characterization of Felid Herpesvirus-1 from Symptomatic Domestic Cats in Egypt

“…One probable explanation is that even though cats are FHV-vaccinated, they can become viral carriers and infect in-contact animals if challenged. Another possibility could be that kittens of persistently infected mothers can get infected and suffer from subclinical or mild infection prior to vaccination, when maternally acquired antibodies are reduced [10].Vaccinations may decrease the overall severity of the disease [20,55]. However, they do not prevent FeHV-1 infection, and as a consequence, the development of FeHV-1 latency [23].…”