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Killing Sharks for a Covid Vaccine?

Updated: Apr 27, 2021

There have been quite a few alarming headlines out there recently discussing how sharks might be sacrificed in order to produce a vaccine for Covid-19: "More Than 500,000 Sharks Could Be Killed to Produce a Coronavirus Vaccine" - Miami Herald, "Sharks face slaughter as drugs companies race to produce coronavirus vaccine made from their livers" - The Sun, "Shark-based coronavirus vaccines spark controversy" - Fox News. You should never blindly believe alarmist stories in the news, without fully understanding the background and the context. So what is the science behind these headlines? Are sharks really going to be killed for use in a vaccine? And why?

It is possible that squalene might be sourced from sharks for a Covid-19 vaccination (Image Source:

The shark product which would be used in a Covid-19 vaccination, is called squalene. This is a low-density oil produced in sharks' livers. The function of squalene is to maintain the shark's buoyancy in the water, and it is also involved in the production of signalling molecules called "steroids", which function as sex hormones and metabolism moderators.

Oils involved in buoyancy-control seeping from a shark liver

Squalene is not only found in sharks. It is actually a chemical which goes a long way back in evolutionary history, so it can be found in all plants and animals. It is especially concentrated within the stomach oils of certain birds, in carrots and certain moulds, alfalfa, elderberry, and lettuce (Fox, 2009). On an industrial scale, squalene can also be extracted from vegetable oils, like rice bran, olives and wheat germ oil. It can even be produced through genetically engineering yeast and bacteria (Pan et al, 2015).

Squalene has been used in vaccinations before because it boosts their efficacy (Fox, 2009). For example, a better immune response is observed when squalene is included in inoculations against malaria, tuberculosis, meningitis and influenza, to name a few (Phan et al, 2020). Squalene which has been extracted from shark livers has been used in vaccination mass-production in the past because it is relatively cheap and easy to get ahold of, not necessarily because it is any more effective than squalene extracted from other sources.

In the case of a major pandemic, like Covid-19, the problem is that the mass production of a vaccination must be extremely fast and efficient or we risk losing many more lives whilst the vaccine is being made. Ideally, the vaccination should require the minimum dose possible whilst still producing an effective immune response (this is known as "dose-sparing"), so that we can inoculate as many people as possible from one batch of vaccine. This allows us to create "herd-immunity", where so many people are vaccinated in a population, that even if someone does get sick, the disease will not be passed on and spread. Therefore, because squalene boosts vaccination efficiency in low doses, it is ideal for use in a Covid-19 vaccination. Pharmaceutical giant Glaxo-Smith-Kline has already made their patented 'AS03' squalene product available to their partners working in Covid-19 vaccination development (Phan et al, 2020).

Threatened sharks (Image Source:

On the other hand, the problem with sourcing squalene from sharks is that we must kill the sharks to get it. The Shark Allies campaign against the use of shark squalene in a Covid vaccine has stated that 500,000 sharks would need to be sacrificed in order to make enough doses for everyone (Shark Allies, 2020). There are many other ways to source squalene, but fishing sharks would be relatively cheap, when compared to other, lab-based methods. Personally, I find it quite upsetting that this many sharks might be killed, just because that is the cheaper option.

On a larger scale, the extraction of such a high number of sharks in a short space of time could also have massive impacts on the ecosystem. Removal of the predators upsets the natural balance in the food-web and could seriously alter the health of our oceans (this is known as a "trophic cascade"). Whatsmore, the majority of sharks are already under serious threat of extinction and boosting their fishing for a Covid-19 vaccine would just be completely unsustainable.

So, there are pros and cons to using squalene sourced from sharks in a Covid-19 vaccine:

I guess it comes down to a question of ethics; is it right to sacrifice sharks to save human lives? In my opinion... NO! Especially if it only being done to save money. However, I'm sure there are many people out there who would happily sacrifice a million sharks if it meant getting their loved one back who they lost to Covid-19. In a perfect world, we would be able to produce enough vaccine for everyone, quickly, whilst not having to sacrifice sharks in the process. But we don't live in a perfect world... We must find a way to balance protecting human life and well-being, whilst simultaneously respecting the natural world.

‘There are better alternatives. The industry must listen!’

- Shark Allies

If you feel that shark squalene should not be used in vaccinations and you would prefer it to be extracted from more sustainable sources, you can sign the Shark Allies petition. If this petition reaches 100,000 signatures in the UK, it legally must be discussed in parliament! So get your voice heard!


Fox CB (2009). Squalene emulsions for parenteral vaccine and drug delivery. Molecules, 14, 3286-3312.

Pan J-J, Solbiati JO, Ramamoorthy G, Hillerich BS, Seidel RD, Cronan JE, Almo SC, & Poulter CD (2015). Biosynthesis of squalene from farnesyl diphosphate in bacteria: Three steps catalyzed by three enzymes. ACS Central Science, 1:2, 77-82.

Phan T, Devine C, Laursen ED, Simpson A, Kahn A, Khandhar AP, Mesite S, Besse B, Mabery KJ, Flanagan EI & Fox CB (2020). Squalene emulsion manufacturing process scale-up for enhanced global pandemic response. Pharmaceuticals, 13:168.

Shark Allies (2020). Shark free products campaign. Access online.

By Sophie A. Maycock for SharkSpeak.

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