Sharks face being slaughtered for the coronavirus vaccine, as conservationists warn as many as half a million could be killed for global supplies.
One of the ingredients in some versions of the Covid-19 vaccine under development is squalene, which comes from the livers of sharks.
Scientists are racing to test a synthetic version, made from fermented sugar cane, which would mean plentiful supplies without threatening shark populations.
Conservationists estimate more than three million sharks are killed each year to obtain their liver oil for various uses, including in cosmetics and machine oil, and fear a sudden rise in demand could push some species closer to the brink.
Squalene from sharks is used in medicine as part of an adjuvant - an ingredient that makes a vaccine more effective and creates a greater immune response.
British pharmaceutical company GlaxoSmithKline uses shark squalene in its adjuvant, which is used in flu vaccines. In May, GSK said it would manufacture a billion doses of the adjuvant for potential use in Covid-19 vaccines.
About 3000 sharks are required to make 1 ton of squalene. Estimates from California-based group Shark Allies suggest that immunising everyone in the world with one dose of a Covid-19 vaccine containing squalene would require about 250,000 sharks, depending on the quantities used. This doubles to half a million if two doses are required, as researchers say is likely.
Many of the species targeted for being rich in squalene, such as the gulper shark and basking shark, are classed as vulnerable, meaning their populations are decreasing and they could become endangered.
Stefanie Brendl, founder and executive director of Shark Allies, said: "Harvesting something from a wild animal is never going to be sustainable, especially if it's a top predator that doesn't reproduce in huge numbers. There's so many unknowns of how big and how long this pandemic might go on, and then how many versions of it we have to go through, that if we continue using sharks, the numbers of sharks taken for this product could be really high, year after year after year."
Silicon Valley company Amryis has produced synthetic squalene for cosmetics for years, but is hoping to apply its technology to remove the reliance on shark fishing in the vaccine industry.
Its method involves the fermentation of sugar cane using yeast, which produces farnesene, a chemical which is then used to produce squalene. John Melo, chief executive of Amyris, says his product is just as effective and doesn't have the same supply chain issues.
It is not yet approved for use in vaccines but Melo said he is in discussions with the US regulator the Food and Drug Administration. "We're in negotiation with three pharma companies, which are looking to buy significant volume," he said.
A spokesman for GSK said the company "explores the potential for alternative sources of its raw materials".
- The Sunday Telegraph / Telegraph Media Group