Poxviruses with their large genomes have been used as a heat-stable vector for vaccines against other viral infections. The french oral antirabies vaccine for foxes was a success. It replicated in the oral cavity of the fox. The recombinant virus has a plasmid encoding the vaccine gene in place of its thymidine kinase gene. This recombinant but not its wild-type parent will grow in the selective cell culture medium containing BUdR (see Russell and Edington, p99).

However a skin-scratch vaccines made with vaccinia or goatpox against rinderpest did not protect as well as traditional live vaccines and there was a risk of the cattle handlers becoming infected with vaccinia, (with generalisation if they had HIV). For safety reasons these vaccines are unlikely to be licensed in future.