October 13, 2020 — Sharks have made international news after Shark Allies, estimated that half a million deep-sea sharks are needed to extract enough squalene for Covid-19 vaccines. The non-profit organization recently came out with the petition to “stop using sharks in a coronavirus vaccine” and use more sustainably sourced alternatives.
But what exactly is ‘squalene’ and why is it possibly in human medicine? Well, first you need to look at basic shark anatomy. Sharks have no swim bladder, unlike bony fish, to help with buoyancy. So, they rely on the lift from their pectoral (side) fins and their large livers that are saturated with oil to maintain their buoyancy in water. Some sharks have a high content of the component squalene (C₃₀H₅₀) in their liver, a highly unsaturated aliphatic hydrocarbon.
According to the Food and Agriculture Organization (FAO), squalene has been/is being used as a “bactericide, an intermediate in the manufacture of pharmaceuticals, organic colouring matter, rubber, chemicals, aromatics, in finishing natural and artificial silk and surface active agents.” Nowadays, squalene is also being used in some adjuvants — common ingredients in vaccines that help create a stronger immune response. What is an adjuvant and why is it added to a vaccine? The Centers for Disease Control and Prevention (CDC) defines an adjuvant as “an ingredient used in some vaccines that helps create a stronger immune response in people receiving the vaccine.” In other words, adjuvants help vaccines work better by helping the body produce an immune response strong enough to protect the person from the disease they are being vaccinated against. The CDC website says that MF59 is a common adjuvant that contains shark-derived squalene. It’s currently found in the Fluad influenza vaccine, licensed for adults 65 or older, and has been used in USA flu vaccines since 2016 with an “excellent safety record.” According to the World Health Organization (WHO), since 1997 a dose of the influenza vaccine (such as FLUAD or Chiron) contains about 10 megagrams of squalene “to make the vaccine more immunogenic.”