Efficacy of a recombinant equine influenza vaccine against challenge with an American lineage H3N8 influenza virus responsible for the 2003 outbreak in the United Kingdom

Abstract

Fifteen influenza-naive Welsh mountain ponies were randomly assigned to three groups of five. A single dose of a recombinant ALVAC vaccine was administered intramuscularly to five of the ponies, two doses, administered five weeks apart, were administered to five, and the other five served as unvaccinated, challenge controls. Two weeks after the completion of the vaccination programme, the ponies were all challenged by exposure to an aerosol of influenza virus A/eq/Newmarket/5/03. Their clinical signs were scored daily for 14 days according to a standardised scoring protocol, and nasal swabs were taken daily for 10 days to monitor the excretion of virus. The challenge produced severe clinical signs of influenza (fever, coughing, nasal discharge and dyspnoea) in all five control ponies, but the vaccinated ponies developed only mild disease, consisting of a serous nasal discharge lasting for only one day. The excretion of virus was almost completely suppressed in the vaccinated ponies, but the control ponies shed the virus for up to seven days after the challenge.

Protection, systemic IFNγ, and antibody responses induced by an ISCOM-based vaccine against a recent equine influenza virus in its natural host

“…The signs were scored using a standardised protocol [7]. On the same days, rectal temperatures were measured.…”

Antigenic and Genetic Evolution of Equine Influenza A (H3N8) Virus from 1968 to 2007

“…Infection in individuals with partial immunity can lead to virus shedding, can occur in vaccinated animals in the absence of clinical signs, and is more likely to occur if the vaccine strain is antigenically dissimilar to the infecting isolate (8,26,27). Animal challenge studies are considered the gold standard to test the degree of clinical protection afforded by vaccine strains in horses (7,12).…”

Recombinant Nipah Virus Vaccines Protect Pigs against Challenge

“…Canarypox virus (ALVAC) vaccine vectors induce antibody and cytotoxic T-cell responses, critical in the immune defense against viruses, to vectored viral antigens in a range of mammalian species (12,14,25,29). Replication of canarypox virus vectors is abortive in mammalian cells, eliminating the safety concerns that exist for vaccinia virus vectors.…”