In 2024, salmon farming ranked as Chile’s third-largest export industry, with a production of 708,278 tons and revenues exceeding US$5.768 billion. Infectious diseases accounted for 23.6% of mortalities, causing significant economic losses. Pentavalent vaccines targeting key pathogens (P. salmonis, IPNV, ISAV, A. salmonicida, and V. ordalii) are the primary preventive strategy. However, combining these with other formulations may reduce field performance. This study evaluated the safety and efficacy of FISHVAC®5S under both laboratory and field conditions, in comparison with competitor vaccination schemes. Monitoring extended through harvest, including side effect assessment, to validate its suitability for long-term health programs.
Laboratory trials included challenges with both genogroups of Piscirickettsia salmonis and the two IPN virus genotypes circulating in Chile. Immune response was evaluated via CD4 and CD8 marker expression, which increased post-vaccination and during infection. Efficacy was assessed at 600, 1200, 1800, and 2400 degree-days (DD) post-vaccination, with RPS end-point values exceeding 85% for both SRS and IPN diseases. At 900 DD, fish vaccinated with FISHVAC®5S showed greater final weight than those vaccinated with a competitor’s product. Safety evaluations showed no peritoneal adhesions above grade 3, with grades 0 to 2 being predominant.
In the field, two strategies were tested: FISHVAC®5S + live vaccine and competitor vaccine + live vaccine. Kaplan-Meier survival analysis showed no significant differences, confirming FISHVAC®5S compatibility with co-administered vaccines. Additionally, a monitoring plan evaluated a vaccination strategy combining FISHVAC®5S, FAV autogenous vaccine, and a live P. salmonis vaccine. Peritoneal adhesions and melanosis were assessed at 600, 1000, and 2000 DD and at harvest. No adhesions above grade 3 were observed, with grades 0–2 present in 89% of cases.
These findings confirm that FISHVAC®5S is a safe, effective, and flexible option for long-term vaccination programs in salmon farming.