6

Holly Galvin, Charlotte Adams, Patrick Salisbury, and Nathan Shemesh

Chapter Overview

Squalene, found in shark livers, is a chemical that strengthens immune responses. 500,000 sharks would be killed if a shark-based COVID-19 vaccine is approved. The goal of this project is to find a viable vaccine alternative to those using shark-based squalene in order to preserve the shark population. mRNA vaccines, DNA vaccines, and plant-based squalene alternatives were found to be possible solutions, with ranging pros and cons to each.

Sharks and Ecosystems

Sharks are one of the most biodiverse predators in the world, existing for over 43 million years and serving as an apex predator for the world’s oceans (Ferretti et al., 2010). In the classic reef ecosystem, sharks act as generalists, meaning that they prey on a wide range of species within the reef habitat (Heupel et al., 2014). Sharks are also mobile predators, meaning they rarely spend their time at a single reef and can roam from reef to reef in search of prey, providing predation to many ecosystems (Ferretti et al., 2010). Due to these factors, sharks often act as keystone species in underwater ecosystems.

Studies have shown that when sharks are removed from an ecosystem, many negative effects are likely to occur within the reef habitat, including trophic cascades and even complete ecosystem collapse in some instances (Barley et al., 2017). One study found that reefs lacking the predation from sharks had less coral and instead more seaweed, as the lack of predation meant that coral-eating species were overabundant and able to consume an excessive amount of the coral (Ferretti et al., 2010). Another study showed that shark prey species often had smaller eyes and fins in habitats that had reduced populations of sharks due to the lack of natural selection in breeding patterns. This study shows the importance of sharks in creating predation to maintain healthy populations of species (Hammerschlag et al., 2018). Finally, another study showed that when sharks are removed from an ecosystem, the zooplankton population increases greatly. Zooplankton produces CO2, so this increase in population results in an increase in CO2 levels, which contributes to ocean acidification and climate change (Strafford, 2020).

Squalene and COVID-19

Squalene is a chemical compound often used for vaccine applications due to its properties that include high surface tension, stability in different situations, and biocompatibility (Fox, 2009). Squalene can often be found being sold alone as a supplement or in other cosmetic products. Along with these uses, squalene is a type of compound known as an adjuvant, meaning that squalene elicits a stronger immune response when used as an ingredient in a vaccine. Using adjuvants can be helpful when vaccinating people with reduced immune responses (Gupta & Gupta, 2020). Squalene is used in the second most popular adjuvant, known as MF59 (Gupta & Gupta, 2020).

In December of 2019, the COVID-19 pandemic began in Wuhan, China, and spread globally in a few short months. The symptoms of the disease vary greatly from person to person, ranging from people that are asymptomatic all the way to effects such as organ failure, severe pneumonia, or even death (Gupta & Gupta, 2020). As of October 2020, the virus had infected over 37 million people and killed over a million worldwide (Johns Hopskins University, 2020). The effects go beyond deaths, costing the world an estimate of $8.1-15.8 trillion globally as of October 2020 and putting the world on the brink of economic collapse (Schwab, 2020). Although there is currently no vaccine for the disease, this is likely to change as several different companies are on the brink of having a vaccine available for public use.

Squalene Harvesting For Vaccines

Currently, over 3 million sharks are killed each year due to the harvesting of squalene. When added to the 100 million sharks per year already harvested due to bycatch and the shark finning trade, the pressure on shark populations becomes immense (Aridi, 2020). The most common types of sharks harvested for squalene are deepwater species because these species’ livers contain a higher concentration of squalene than sharks living in shallow water. Due to deepwater sharks having longer lifespans and reduced breeding capabilities, these sharks are some of the most susceptible to overfishing because a lot of time is needed to allow the population to recover and grow (Aridi, 2020). In particular, a species known as the gulper shark is most commonly harvested for squalene. In the past, gulper sharks were a common bycatch, but as the need for squalene has risen, gulper sharks have more frequently become a target species in fishing operations (Roth, 2018).

Currently, 17 of 176 COVID-19 vaccine candidates contain squalene as an ingredient (Aridi, 2020). If one of these candidates were to be approved and distributed to a majority of the world’s population, an estimated 500,000 additional sharks would need to be harvested to fill this demand (Aridi, 2020). New research on methods to save these sharks would not only assist in saving shark populations in the present day but could also create a more sustainable source of squalene for other applications in the future. Beyond saving resources, new research into squalene alternatives could help raise public awareness about the pressure on shark populations, along with their importance. Within the government, new research showing promising alternatives could help promote the regulation of squalene and subsequently reduce the targeting of shark populations. A vaccine using an alternative adjuvant or no adjuvant at all might be more likely to be approved if research showed that those vaccine types are more sustainable.

Approach to the Problem

The team referred to many resources to investigate viable alternative vaccine options to a shark-based squalene vaccine. There were many considerations to keep in mind when choosing an alternative that was appropriate for the COVID-19 pandemic. The vaccine should not compromise human safety or create more health damage when given to treat COVID-19. The vaccine also needed to be effective so that the majority of the population can be protected from the disease to limit spread. Public demand for the vaccine is very high due to the loss of life and money from the virus, so the vaccine needed to be approved as soon as possible to protect the world from more loss. The vaccine also needed to be affordable in order to allow everyone to access treatment regardless of wealth or status. Affordability was especially important when thinking of developing countries with high populations, and the economic requirements to make sure everyone in the world has access to a vaccine. Finally, environmental impacts were examined to see which vaccines preserved the shark population without creating an adverse environmental impact. To find these vaccines, research journals outlining different vaccine types were looked at in order to understand the functioning of each vaccine type. News articles were also examined to keep up-to-date information on the state of COVID-19 vaccine production, as new developments were announced each day. Finally, interviews with experts in the vaccine and health services industries, Derek Adams and Gregory Galvin, helped guide the research.

Squalene Vaccines

Squalene, as a component of the MF59 adjuvant, is used in a type of DNA vaccine called a fragmented or pieces and parts vaccine (Adams, 2020; Gupta & Gupta, 2020). In a fragmented vaccine, proteins from viruses are given and the body reacts and creates immunity to these proteins so that when it sees these proteins again, the body has an immune response (Adams, 2020). Adjuvants are typically required in these vaccines to be able to create a sufficient immune response that the body remembers long enough to protect against the disease the vaccine is targeting (Adams, 2020). Adjuvants can be different components of the vaccine depending upon the vaccine formula. Adjuvants, such as the MF59 containing squalene, can be excipients: an inactive substance that serves as a vehicle for the active vaccine ingredient or a part of the active vaccine itself (Adams, 2020).

Shark livers are not the only source of squalene. Squalene can be found in many other natural sources such as plants, fungi, yeast, or microbes. Olive plants are the most viable source of non-shark-based squalene. Extracting squalene out of other natural resources is a more sustainable alternative to shark-based squalene. The use of these other sources of squalene would not only help preserve the shark population but also help the long-term availability of COVID-19 vaccines because once the sharks are killed in production, they will not be a viable source of squalene due to the extinction of the species.

Plant-based squalene is more expensive than shark-based squalene. 30 kilograms of olive oil on average can make 300 grams of squalene, the same amount of squalene that one shark can make (Gohil et al., 2019). The process to elicit squalene from plants also takes much longer because plants need to be grown and harvested, while sharks are already available for capture in the ocean. Access to oil-based plants also varies from area to area, so certain geographic regions will not have access to plant-based squalene. In order to grow the number of plants needed to fulfill a COVID-19 vaccine, a subsequent amount of land would have to be converted to farmland, having a secondary negative environmental effect. Though plant-based squalene would help preserve the shark population, unfortunately, due to the timespan and demand for COVID-19 vaccines, plant-based squalene is not a viable option for the current pandemic. It is important to note that in the future with more research and development, plant-based squalene may become feasible for future vaccines.

mRNA Vaccine

mRNA vaccines are leading in the current COVID-19 vaccine production. Moderna and Pfizer are two of the vaccine companies currently petitioning for US FDA approval. The chemical composition of an mRNA vaccine is environmentally friendly to the shark population because there is no squalene used in the vaccine. Instead, mRNA from COVID-19 is inserted into human cells, tricking the cells into thinking that the COVID-19 mRNA is human mRNA. The cells will then translate this mRNA into protein, known as spike protein (CDC, 2020). The white blood cells then recognize that this protein is foreign, so they build an immune response to attack and eradicate the spike protein. This builds the body’s immunity to the COVID-19 disease, similar to the way the body would naturally build immunity through infection. Since the vaccine does not use a living strain of COVID-19, there is no chance that the vaccine will transmit the disease and infect the patient (CDC, 2020). Contrary to a popular belief, the mRNA vaccine does not alter human DNA because the mRNA is converted to protein outside of the nucleus (CDC, 2020).

The original goal for the effectiveness of the COVID-19 vaccine set forth by the US FDA was 50% (FDA, 2020). Both the Moderna and Pfizer vaccines have shown to be much more effective in clinical trials than the original goal, at 95% effective in preventing contraction of COVID-19 (Gallahger, 2020). Two doses are required for both the Moderna and the Pfizer vaccines (Gallahger, 2020). 43,000 participants were a part of the Pfizer trial, and the only side effects reported were fatigue and headache (Pfzier, 2020). 30,000 participants were a part of the Moderna trial (NIH, 2020), and the only side effects reported were fatigue, muscle and joint pain, and headache (Wadman, 2020). About 2% of subjects given the vaccine reported more severe side effects such as high fevers (Wadman, 2020).

Though both the Moderna and Pfizer vaccines have been proven safe in clinical trials, mRNA vaccines have never been FDA approved for any other disease (Cohen, 2020). Though mRNA vaccines have been used in trials for diseases such as Zika and Rabies, they have never been approved for public usage. Before COVID-19, the quickest vaccine to be produced was the mumps vaccine, which took four years (Akpan, 2020). In comparison, both the Moderna and Pfizer vaccines have been designed, tested, and applied for approval in under a year. Experts are unsure whether the fast-tracking through clinical trials for the vaccine has allowed potential side effects or long-term effects of mRNA vaccines to go unnoticed.

The Pfizer vaccine is ready to be given to the elderly and essential workers as early as mid-December 2020 in the USA, once they receive FDA approval (Pfizer, 2020). On December 2nd, 2020, the Pfizer vaccine was approved in the UK and has started to be distributed to high-risk citizens (Roberts, 2020). 50 million doses are expected to be completed by the end of 2020, with another 1.3 billion projected for 2021 (Pfizer, 2020). The ability of the vaccine to be produced in a short amount of time is essential for the timeframe of COVID-19. The Moderna vaccine costs $33 per dose and the Pfizer vaccine costs $20 per dose wholesale, putting them on the pricier end of the vaccine cost range (Gallahger, 2020). Though certain countries such as the UK are subsidizing the vaccine, this could overall affect the accessibility of the vaccine to poorer communities, especially those in developing countries.

Unfortunately, mRNA vaccines need to be kept at very low temperatures. The Moderna vaccine needs to be kept at -20 degrees celsius, and the Pfizer vaccine needs to be kept at -70 degrees celsius (Gallahger, 2020). Low refrigeration temperatures can add a secondary environmental effect on the production of these vaccines because energy is needed to keep them cold. Dry ice is usually utilized for this, which is CO2 gas that has been compressed (Pfzier, 2020). This can allow for the release of CO2 into the environment, which can contribute to climate change. Even with this added CO2 rate, it would not be more than the amount of CO2 created by zooplankton in the ocean if sharks are removed from the ecosystems. Overall, an mRNA vaccine is a viable and effective solution even with its flaws, and the vaccine will help preserve the shark population if approved.

DNA Vaccine

The leading DNA vaccine for COVID-19 is being developed by the company AstraZeneca in partnership with Oxford University (Johnson & Steckelberg, 2020). There are many types of DNA vaccines that have been proven to work on many infectious diseases such as chickenpox, Hepatitis A, Hepatitis B, and the seasonal influenza virus (Adams, 2020). The AstraZeneca vaccine is a viral vectored vaccine and uses an adenovirus, in this case, a harmless cold-causing virus that has been modified to include genetic material from the COVID-19 virus (Branswell& Feuerstein, 2020; Johnson & Steckelberg, 2020). When injected into a human body, the adenovirus introduces the immune system to the spike protein that sits on the exterior of the COVID-19 virus and causes cells to make replicas of the spike proteins, thereby training the immune system to recognize the protein as foreign and develop an immune response (Branswell & Feuerstein, 2020; Johnson & Steckelberg, 2020).  Moreover, because the AstraZeneca vaccine is a viral-vectored vaccine, the vaccine does not contain adjuvants and does not contain squalene (Adams, 2020). Therefore, if the AstraZeneca vaccine were to be widely distributed, the production of the vaccine would not negatively affect shark populations.

Since the developing Oxford-AstraZeneca vaccine is a type of vaccine that has been extensively tested and proven to work on many diseases, a DNA vaccine is a more reliable type of vaccine than a new mRNA vaccine that has never been approved by the FDA. In addition, if widely distributed, AstraZeneca’s vaccine would cost approximately $4 per dose, significantly cheaper than both mRNA options (Gallahger, 2020). Furthermore, the AstraZeneca vaccine can be kept at regular refrigerated temperatures for up to six months, making it more environmentally friendly and easier to distribute to more people as quickly as possible because specialized facilities to store the vaccine will not have to be built (Branswell & Feuerstein, 2020; Johnson & Steckelberg, 2020).

In contrast to the average 95% efficacy rate of the two mRNA candidates, the AstraZeneca vaccine has an average efficacy rate of 70% (Branswell & Feuerstein, 2020). Furthermore, the preliminary results from the clinical trials of the AstraZeneca vaccine have raised some concerns. The results were based on 131 COVID-19 cases among 11,363 participants; however, the company didn’t release how many cases were found in each of the two groups of participants who were given different amounts of the vaccine (Branswell & Feuerstein, 2020; Robbins & Mueller, 2020). One group that consisted of 2,800 participants was given one half-dose of the vaccine followed by a full dose a month late, which yielded an efficacy rate of 90% (Robbins & Mueller, 2020). However, the second group which consisted of 8,900 participants were given two full doses of the vaccine at the same rate, which yielded an efficacy rate of 62% (Robbins & Mueller, 2020). These results are troubling to several experts such as Anthony Fauci especially since it was due to a mistake that the smaller group of participants received a half dose initially (Robbins & Mueller, 2020). This suggests that further testing needs to be done to be certain that the Oxford-AstraZeneca vaccine is safe and effective.

https://youtu.be/yp9p0ieLZZ0

Figure 4: How the Various COVID-19 Vaccines Work. Video by CNBC Television, 2020.

Conclusion

Squalene-based vaccines are not a recent development, and the usage of squalene in vaccines such as those for influenza makes them more appealing to use in future COVID-19 vaccines. Vaccines such as FLUAD have been around for decades and produced effective disease immunity in people that otherwise would have difficulty reacting to the antigen within the vaccine. In particular, this characteristic of squalene and other adjuvants “boosting” the effectiveness of vaccines for those with compromised immune systems makes squalene and other adjuvants a very effective tool in creating a highly effective vaccine, especially for the high-risk population associated with COVID-19. However, what squalene gains in effectiveness it lacks in sustainability. Shark-based squalene for vaccines would only add to the already immense strain on shark populations due to overfishing, climate change, and habitat loss. The increased costs, timespan to produce plant-based squalene, and potential alternative environmental effects of production means that no plant-based alternative is appropriate for COVID-19, although it is worth noting that with further research and development, one of these alternatives may be viable in the future for other vaccines.

Although vaccines including adjuvants are a proven effective type of vaccine, the unprecedented nature and pace of development of the COVID-19 vaccine have led to alternative vaccine types becoming the more likely candidates for approval. mRNA vaccines such as the Moderna and Pfizer vaccine were unimaginable even a few years ago but have made it into the late stages of clinical trials showing promising results. Although these vaccines seem almost magical with their effectiveness, mRNA vaccines still have their own set of challenges. The biggest challenge is their cold storage temperatures which could lead to a possible secondary environmental effect. DNA vaccines, such as the Oxford-AstraZeneca vaccine candidate, follow a more proven vaccine composition and are less expensive. However, trials have shown inconsistent effectiveness suggesting that further development and trials will need to be completed to produce a safe, reliable, and effective vaccine for the masses. Keeping in mind that a possible squalene-based vaccine would likely have its own set of drawbacks even beyond environmental effects, these alternative vaccines provide several compelling reasons to ditch squalene. Instead of sacrificing the sharks for the greater human good, it appears as if advances in science and medicine have led to a situation where both sharks and humans will benefit.

However, this does not mean that sharks are out of the water. Both the cosmetic industries and other vaccines continue to use shark-based squalene, and in the future, alternatives to this shark-based squalene must be aggressively pursued to save a species already on the brink. Researchers will need to pursue further development of these alternative sources in order to create a sustainable source of squalene for the future. Governments will need to increase regulation of shark harvesting even further, possibly even regulating squalene as a substance to assure that the amount of sharks harvested is greatly reduced from current numbers. Finally, the public as a whole needs to take action and get involved. Saving shark populations needs to become a global effort, and every person supporting these efforts will make a difference.

Acknowledgments

A special thanks to our advisors Professor Marja Bakermans, Professor William San Martin, and PLA Sam Grillo for advising this. Also, a huge thank you to our wonderful expert interviewees Dr. Gregory Galvin and Derek Adams, Ph. D for taking the time to speak with us.

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