But Norwegian grower Alsaker Fjordbruk wants more time before it draws firm conclusions about the vaccine, and also points out that it is twice as expensive as other PD vaccines.
Alsaker Fjordbruk has 23 food fish licences and an annual production of about 30,000 tonnes of salmon. It produces 18 million smolts a year at four hatcheries.
Speaking at Europharma’s annual fish health seminar in Lofoten, the company’s smolt sales manager, Endre Jenssen, said that finding a good enough vaccine against PD has for many years been a major problem.
What is Clynav?
- Clynav was the first DNA vaccine for any species to gain approval in Europe (in June 2017).
- It has been developed to help protect specifically against salmonid alphavirus subtype 3 (SAV 3), a subtype that causes PD in Norway but is not present in Scotland, where less-virulent SAV strains are found in salmon.
- Elanco does, however, believe that the vaccine will be effective against all SAV strains and has been selling Clynav in Scotland and Ireland since February this year.
- The vaccine contains plasmid deoxyribonucleic acid as its active substance, which stimulates active immunity.
There had until now been costly vaccines that had some poor effects. These vaccines had also caused some vaccine injuries or side effects on the fish, so that they had poorer slaughter quality.
The company has partly succeeded in limiting PD on its own sites with various measures, one of which is to use the best possible PD vaccine. The company was the first in Europe to use Clynav vaccine in January last year, when 500,000 spring 2018 smolts were vaccinated.
Jenssen told Fish Farming Expert’s sister site, Kyst.no, that the conclusion so far is that the vaccine seems to work well against PD. The company has not observed any deformities or vaccine damage so far with the use of this vaccine.
He pointed out that the company has only slaughtered fish from one cage so far, and therefore believes that it should have at least one year before drawing any conclusions on the effect of the vaccine.z
He also emphasised that one must be sure that the correct vaccine dose of 0.005 ml is appropriately administered to the fish, therefore it is safer to use a vaccination machine, as the company has now done.
The company has vaccinated the following:
Autumn fish 2018: Vaccinated about 50% with Clynav
Spring fish 2019: Vaccinated about 85% with Clynav
On the negative side, it is worth mentioning that Clynav’s price is more than twice as high as another PD vaccine, and costs close to NOK4 per dose.
Jenssen added that there have also been major challenges with access to enough vaccine, something that also applies to autumn smolt in 2019. The company therefore hopes that Clynav’s manufacturer, Elanco, manages to increase the production of the vaccine.