The UK Veterinary Vaccinology Network was among the sponsors of this year's Cheltenham Science Festival, which took place from June 7 to 12. During the festival, Adrian Hill and Andrew Pollard, of the Jenner Institute, and Bryan Charleston, of the Pirbright Institute, represented the network and discussed the development of genetically modified vaccines and the issues surrounding them in animal and human health. Madeleine Clark sums up their presentation.