Evidence for a long-lasting single administration contraceptive vaccine in wild grey seals

J Reprod Immunol. 1997 Nov 1;35(1):43-51. doi: 10.1016/s0165-0378(97)00047-8.


A single-administration birth control vaccine based on liposome delivery of porcine zona pellucida antigens reduced pup production in grey seals (Halichoerus grypus) by about 90%. Anti-porcine zona pellucida titers of individual seals with two or more recaptures were variable but without a diminishing trend during the 5 year post-immunization period. Seals that produced at least one or more pups during the 2-5 year post-immunization period when the vaccine is fully effective, had an average anti-porcine zona pellucida titer of 5% of the reference serum. In contrast, the subset of seals that did not reproduce but were recaptured during the breeding season had an average titer of 31% of the reference serum. As measured by antibody titers and pup production, there were no differences in efficacy of the vaccine in 14-, 20- and 21-year-old female grey seals.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Animals, Wild
  • Antibodies / blood
  • Contraception, Immunologic / methods
  • Contraception, Immunologic / veterinary*
  • Drug Compounding
  • Female
  • Fertility
  • Liposomes / pharmacology
  • Longitudinal Studies
  • Pregnancy
  • Seals, Earless*
  • Swine
  • Vaccination
  • Zona Pellucida / immunology*


  • Antibodies
  • Liposomes