Cattle were vaccinated with differing doses of an equal mixture
of capripox-rinderpest recombinant viruses expressing either the fusion
protein (F) or the haemagglutinin protein (H) of rinderpest virus.
Animals vaccinated with 2 × 104 p.f.u. or greater of
the combined viruses were completely protected against challenge, 1
month later, with both virulent rinderpest and lumpy skin disease
viruses. Vaccination with any of the doses did not induce any adverse
clinical response in the animals or transmission of the vaccine virus
between animals. All cattle challenged 6 or 12 months after vaccination
with 2 × 105 p.f.u. of the mixture of recombinant
viruses were protected from severe rinderpest disease. Ten out of 18
were completely protected while the remaining 8 developed mild clinical
signs of rinderpest. Cattle vaccinated with the recombinant vaccines
after prior infection with the parental capripox virus showed more
marked clinical signs of rinderpest after challenge with virulent
rinderpest, but 9 out of 10 recovered, compared with 80% mortality in
the unvaccinated controls.