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The constant march of science to find a vaccine capable of ending the coronavirus pandemic may come at the expense of another species: sharks.
Shark researchers in Miami, Florida, United States, say they are concerned about a key ingredient used to make vaccines more effective, squalene, an oily substance found in plants and even human skin. , but it is particularly concentrated in shark liver.
The practice of using shark-derived squalene as a booster to stimulate a stronger immune response to a vaccine is not unique to the coronavirus vaccine. The compound has been shown to be safe and effective in millions of vaccine doses, primarily in Europe, said Liza Merly, a shark immunologist at the Rosenstiel School of Marine and Atmospheric Sciences at the University of Miami.
“We don’t know exactly what this oil has that allows it to work the way it does,” said Merly.
But squalene in vaccines has been shown to create stronger immune responses, and there are a handful of Covid-19 vaccine candidates who use it for that purpose, most of them in partnership with GlaxoSmithKline, which makes a component derived from squalene. for vaccines.
If one of the vaccine candidates using that component proves effective, it could create a global demand for squalene that could threaten wild shark populations, according to Shark Allies, a nonprofit organization dedicated to protecting wild sharks.
The nonprofit organization produced a rough estimate: It would take about 500,000 sharks to produce squalene for the billions of doses of vaccine needed to inoculate everyone on the planet twice. That spurred international headlines and sparked a pushback from GSK, which has argued that the estimate is too high. But the company has refused to identify the source of its squalene, other than saying that it is extracted from sharks that were fished for other purposes, and that is what worries shark experts.
Catherine Macdonald, a marine conservation biologist and ecologist at UM’s Rosenstiel School, came up with a more advanced estimate and came up with a slightly lower projection of 360,000 sharks needed to produce enough squalene to fuel billions of doses of vaccine.
But Macdonald said the number matters less than the lack of transparency in the shark fishing industry, which is poorly regulated. Fishing for sharks is known to harm wild populations, Macdonald said, primarily in search of fins, but also during hunting for squalene, which is commonly used in cosmetics.
A sudden spike in demand for squalene would be a major concern, he said, in part because liver oil is more abundant in deep-sea sharks that are vulnerable to overfishing.
Although GSK says it is using sharks that were fished for other purposes, Macdonald said that “asking for more transparency in the supply chain is still reasonable.”
“Some fisheries associated with squalene production target deep-sea sharks,” Macdonald said. “We know that deep-sea environments evolve with very low natural levels of disturbance, so each time we have significant effects on deep-sea populations, we know less about them and are less able to detect the effects that we are having. “
Why sharks?
Although squalene is abundant in the natural world, sharks are a preferred target for industries because it does not require much effort to purify the substance from shark livers.
“It’s easier and cheaper than if you wanted to get squalene from, say, olive oil,” said Merly, who did her doctoral work on the medicinal value, or lack of it, of shark cartilage.
As part of her research, Merly discovered a wide range of products that are derived from sharks.
“This is why I know squalene so well,” he said. “But if you try to find out from these companies how they get these things, they are really reluctant to tell you.”
There are sustainable ways to extract squalene from sharks, Merly said, such as extracting it from dogfish sharks, which are actively fished and managed. Those methods have a lower environmental impact than other shark species that are less abundant and target squalene.
Merly said Scandinavian countries, in particular, are known to fish deep-sea sharks for squalene. And Macdonald, the other UM shark researcher, said DNA from threatened shark species has been identified in cosmetic products that use squalene, including products that claim to be vegan.
Squalene is used in a wide range of cosmetics and skin care products, such as moisturizers, lipsticks, sunscreens, bath oils, foundations, eye makeup, body creams, etc.
Due to the lack of transparency in the supply chain, Merly said, “you don’t want to incentivize or add value to a dead shark if you don’t have to.”
“Shark cartilage has no value in human medicine, so it’s a bad thing,” Merly said. “In the case of squalene, it is a little more complicated, because there is a possibility that it will be useful in human medicine.”
Find an alternative
The initial controversy over whether shark-derived squalene in Covid-19 vaccines would lead to the killing of half a million sharks did overlook the nuances of the situation, said Stefanie Brendl, founder and CEO of Shark Allies, the group. which produced the estimate that led to the news coverage.
Brendl said she doubted Shark Allies would intervene in shark-derived squalene because she didn’t want to be seen as questioning a crucial public health need. But the organization, Brendl said, needed to “get ahead of a problem that could potentially lead us in a really bad direction.”
“Is this a hill we want to die on? Do we want to fight Covid vaccines when we have so many other problems? No, ”said Brendl. “But we don’t want it to become another hill.”
Brendl’s group has identified Amyris, a company that makes a plant-derived squalene component for vaccines that would be regulated in the same way as shark-derived squalene by the U.S. Food and Drug Administration, as a potential alternative to shark products.
“We have tried to undermine all the excuses: it is no different, it is just as available, and with plants, you can grow it on any scale you want; it’s a secure supply chain, ”said Brendl.
While GSK has argued that the amount of squalene it would need to make doses of Covid-19 vaccine is a “very small proportion of the animal-derived squalene used worldwide,” it also said it is “actively exploring the potential of alternative sources. of raw materials when possible ”.
“These efforts include the exploration of non-animal derived sources of squalene for future use in the … manufacturing process,” the company said in a statement.
Macdonald acknowledged that she is not a vaccine expert, but said she found no compelling reason why pharmaceutical companies couldn’t switch to plant-derived squalene, which she says remains low-cost, just as effective, and presents no regulatory hurdles. additional.
Given the threats to marine environments from deep-sea ocean ecosystems to Biscayne Bay, Macdonald said plant-derived squalene was a cause that should be easy to overcome.
“There aren’t many times when you can look at a marine conservation problem and say, ‘This actually seems very fixable,’” he said. – Tribune / Miami Herald / Ben Conarck News Service
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