During the last 10 to 20 years vaccination has become established as an important method for prevention of
infectious diseases in farmed fish, mainly salmonid species. So far, most commercial
vaccines have been
inactivated vaccines administered by injection or immersion.
Bacterial infections caused by Gram-negative bacteria such as Vibrio sp., Aeromonas sp., and Yersinia sp. have been effectively controlled by vaccination. With
furunculosis, the success is attributed to the use of
injectable vaccines containing adjuvants.
Vaccines against
virus infections, including infectious
pancreatic necrosis, have also been used in commercial fish farming.
Vaccines against several other bacterial and
viral infections have been studied and found to be technically feasible.
Pasteurellosis, streptococcosis (lactococcosis) and
infections with iridoviruses are candidate diseases for control by immunoprophylaxis in the near future. The overall positive effect of vaccination in farmed fish is reduced mortality. However, for the future of the fish farming industry it is also important that vaccination contributes to a sustainable
biological production with negligible consumption of
antibiotics. A potential side-effect associated with
injectable vaccines is local reactions in the peritoneal cavity. The paper presents recent developments in immunoprophylaxis of fish and some problems that should be addressed by the research community in the years to come.