Aquaculture Vaccine Platforms Are Moving Beyond Injection-Based Immunisation Toward Oral and Immersion Delivery for Salmon and Shrimp

Aquaculture health management is approaching an inflection point in vaccine delivery technology. Injection-based vaccination, while highly effective, has imposed a persistent operational constraint on fish farming at scale: each fish must be individually handled, sedated, and injected, creating labour intensity and fish welfare concerns that limit the economics of intensive production systems. For salmon farming, where vaccination against multiple bacterial and viral pathogens is mandatory for commercially viable operations in Norway, Chile, Scotland, and Canada, injection delivery has been accepted as a necessary production cost. For shrimp, where individual handling is impractical at commercial densities, effective vaccination has remained largely out of reach. Oral and immersion delivery platforms are now advancing to the point where they can meaningfully change this calculus for both species, opening new segments of the aquaculture health market to vaccine-based disease management.

Why Injection Delivery Is Reaching Its Limits

The salmon farming industry has built its biosecurity architecture around intraperitoneal injection vaccination administered at the smolt stage before sea transfer. This approach has delivered substantial results in reducing bacterial disease losses, particularly against furunculosis and vibriosis pathogens, and has dramatically lowered antibiotic use relative to pre-vaccination era operations across Norwegian, Chilean, and Scottish farms. However, as salmon production scales and farm densities increase in response to global demand growth, the labour intensity of injection vaccination has become an increasingly acute operational bottleneck that constrains throughput at sea transfer facilities.

Vaccine-induced peritoneal adhesions are a documented fish welfare issue associated with oil-adjuvanted injectable vaccines. The adhesions cause internal scarring that can affect fillet quality, raise welfare audit concerns for premium market certifications, and increase post-vaccination mortality rates when adjuvant formulations are not precisely managed. The search for adjuvant formulations that maintain protective immune response while reducing adhesion incidence has been ongoing for a decade with only partial success across commercial formulations. Newer delivery platforms that avoid intraperitoneal injection entirely would resolve this welfare concern while simultaneously addressing the labour intensity bottleneck at vaccine stations.

For shrimp, the challenge is more fundamental than a delivery format question. Crustaceans lack the adaptive immune system that conventional vertebrate vaccines target, operating instead through innate immunity mechanisms that differ substantially from the antibody-mediated responses that injection vaccines are designed to generate. Conventional vaccine approaches developed for fish or terrestrial animals do not translate to shrimp immunology. The industry has historically managed shrimp disease through biosecurity protocols, selective breeding programmes for disease resistance, probiotic supplementation, and antibiotic treatment where regulatory frameworks permit. The development of effective oral immune stimulants and RNA-based platforms capable of priming innate immune responses represents a genuinely new disease management capability for the shrimp sector, not merely an alternative delivery format for existing technology.

Oral Vaccine Platform Development

Oral vaccine delivery for fish requires addressing two core and interrelated technical challenges. First, the antigenic payload must be protected from the highly acidic and enzyme-rich environment of the fish gastrointestinal tract, which would degrade conventional protein antigens before they reach immune-competent tissue in the intestinal wall. Second, the vaccine must achieve sufficient uptake through the intestinal mucosa to generate a protective systemic immune response comparable to that produced by direct intraperitoneal injection. Microencapsulation technologies using alginate, chitosan, and poly-lactic-co-glycolic acid polymer matrices have advanced considerably in addressing both challenges, with several formulations now demonstrating protection equivalent to injection benchmarks in controlled pathogen challenge trials for specific bacterial pathogens.

The regulatory pathway for oral aquaculture vaccines has also progressed in key markets, reducing the commercial risk that had previously deterred investment in oral platform development. Norway's regulatory framework, which sets global standards given the country's position as the dominant salmon-producing nation, has approved oral booster vaccine formulations for several bacterial pathogens, creating a regulatory precedent that other major salmon-producing countries are beginning to follow. The commercial viability of oral delivery also depends critically on achieving antigenic stability through the pellet manufacturing, handling, and storage process, which requires close technical collaboration between vaccine developers and commercial feed manufacturers to integrate antigen incorporation into existing high-throughput pelleting lines without degrading biological activity.

Immersion Delivery and RNA Platforms for Shrimp

Immersion vaccination, where fish are briefly bathed in a dilute antigen solution that is absorbed through gill tissue and skin mucosa, is already established for first-feeding fry and fingerlings where fish size makes injection impractical. Extending this approach to larger fish and developing more efficient antigen uptake formulations capable of generating durable immune responses is an active area of commercial development. Several salmon vaccine companies are working on immersion booster protocols that could supplement or partially replace injection regimens at sea transfer, reducing the frequency of individual fish handling required over the full production cycle.

For shrimp, RNA interference and double-stranded RNA platforms have shown considerable promise in research and early commercial settings for activating innate immune pathways against white spot syndrome virus, the most economically damaging shrimp pathogen globally, as well as against Vibrio and early mortality syndrome pathogens. Oral delivery of dsRNA through medicated feed pellets can achieve systemic distribution through the shrimp digestive system and has demonstrated statistically significant mortality reduction in controlled challenge studies. Several companies with dsRNA platform expertise have moved from laboratory demonstration to large-scale pilot trials with commercial shrimp producers in Southeast Asia and Ecuador. The production cost of therapeutically active dsRNA at aquaculture application scale remains a constraint on commercial adoption, but continued investment in fermentation-based RNA manufacturing is reducing costs along a trajectory that should reach commercial viability for high-value shrimp applications within the medium term.

The regulatory pathway for dsRNA shrimp health products is also developing in parallel with the commercial pipeline. Several major shrimp-producing countries including Thailand, Ecuador, and Vietnam are actively reviewing registration frameworks for RNA-based immune stimulants, recognising that the economic cost of disease-driven production losses in their aquaculture sectors creates strong policy motivation to expedite approval pathways for effective preventive health tools. The distinction between feed additives, veterinary medicines, and biological products is being clarified in regulatory frameworks that were developed before RNA-based platforms became commercially relevant for aquaculture, and the outcome of these classifications will determine the regulatory burden and commercial timeline for dsRNA products in each market. Early regulatory approvals in one major producing country will create demonstration data that accelerates approvals in others, as has occurred with several conventional aquaculture health products over the past decade.

Top 10 Companies

1. MSD Animal Health , A leading aquaculture vaccine developer with a broad portfolio covering bacterial and viral pathogens in salmon and other commercially important farmed fish species.
2. Zoetis , Has expanded its aquaculture health portfolio through the Pharmaq acquisition and internal development, with oral and immersion delivery programmes in active research and development.
3. Elanco Animal Health , Competes across salmon vaccine categories and is investing in next-generation delivery platforms as part of its aquaculture growth strategy.
4. Pharmaq , Norway-headquartered aquaculture health specialist integrated into Zoetis, with deep regulatory expertise in Norwegian and Chilean salmon vaccine markets and established commercial relationships with major salmon farming groups.
5. Benchmark Holdings , UK-listed aquaculture genetics and health company with vaccine development capabilities, sea lice treatment products, and a commercial focus on integrated salmon health management.
6. BioMar Group , Major aquafeed producer that is a critical commercial partner for oral vaccine integration into salmon and shrimp feed pellet manufacturing at commercial scale.
7. RNAGri , Specialised dsRNA platform company focused on shrimp immune priming, with commercial-scale pilot trials underway with major shrimp producers in Thailand, Vietnam, and Ecuador.
8. Cargill Aqua Nutrition , Global aquafeed manufacturer positioned as a delivery channel partner for oral vaccine and immune stimulant incorporation into commercial shrimp and salmon compound diets.
9. Mowi , World's largest salmon farmer and an important commercial validation partner for next-generation vaccine delivery platforms given the scale and geographic diversity of its farming operations.
10. Charoen Pokphand Foods , Major Southeast Asian aquaculture and agri-food conglomerate whose shrimp farming operations represent a high-value commercial target for dsRNA and oral immune platform developers.