If travelling horses abroad to regions where the WNV is active or if in the future WNV emerges in Great Britain, vaccination, with regular boosters may be recommended. There are currently two WNV vaccines available for administering to horses in Great Britain, licensed from 5 or 6 months of age to reduce the number of viraemic horses and the severity and duration of clinical signs. Several years’ experience of the use of these vaccines for horses in North America suggests that they are safe to use and, if used correctly, effective in preventing clinical disease. Vaccination can interfere with serological testing as the Enzyme Linked Immunosorbent assay (ELISA) cannot differentiate infected from vaccinated animals (so called DIVA capability) and it may therefore interfere with serological testing.
Consult your veterinary surgeon. See Appendix 8 for vaccine details.