Sharks, vaccines, and more sharks
Sharks are cool. So are vaccines. But some vaccines result in the deaths of sharks.
Hello!
A lot happened this week, so I will get right to it. I want to talk about sharks. And how there’s a relation between sharks and some vaccines.
I’ll get to that in a little bit but before that just a little bit more about just vaccines.
Talking about vaccines.
I sat down with Shrikant Joshi on his podcast show to talk about vaccines. The podcast episode is here. He did a good job of making me sound almost intelligible. Let me know what you think because I personally cannot bear to hear the sound of my own voice.
mRNA vaccines: why now?
I mentioned something on Twitter that I feel is worth repeating here to clear any misconceptions about mRNA vaccines. The leading COVID-19 vaccines by Pfizer and Moderna are mRNA vaccines. Synthetic RNA is much easier to manufacture than proteins in bulk or inactivated or "weakened" versions of viruses for vaccines. We’ve heard a lot of the negatives of how mRNA degrades easily if not frozen. But its ease of creation is a point that is overlooked.
So, you might wonder why we didn't have mRNA vaccines before. This has to do mainly with three technical advances over the last few years.
Stability. mRNA is unstable and difficult to get inside cells. But by encasing it in fat molecules known as lipid nanoparticles (LNPs), delivery and stability have been improved. Not all LNPs are made equal though. Moderna's LNP is likely different from Pfizer's and so it is more stable at higher temperatures.
Reactivity. "Foreign" RNA triggers an immune response (instead of the protein that it helps the body make). The key here is a scientific study that showed that if you modify the nucleosides in the mRNA then it is safe to use. Synthetic nucleosides suppress the immune system's reaction to the RNA itself.
Efficiency. mRNA has to be translated into viral proteins inside host cells to be effective as a vaccine. However, until it was modified and stable, foreign mRNA only produced low levels of protein, not enough to elicit the necessary immune response.
In theory, you can use this technology to create any polypeptide, not just for SARS-CoV-2, but for other infectious diseases. And also for cancers. This is truly a paradigm shift.
(Image courtesy Pixabay. CC BY 3.0)
I got bested by an eight-year-old.
I asked an eight-year-old what he liked about sharks and he wrote and emailed a 25-item list with scientific facts (some of which I didn’t know). Thanks a lot, Arhan. Kids these days!
Apart from fact-checking the list, merging a few of the points, and lightly proofreading, here is the list.
I love sharks because...
Sharks are strong. They have collapsing jaws. Different sharks have different bite force.
They have a lot of teeth that are sharp. For example, some have up to 30,000 sharp teeth. Sharks even have teeth on their skin.
They have been around for around 423 million years and have survived four out of five mass extinctions.
Sharks are on the top of the food chain. They are known as apex predators. They can hunt very well.
They eat mostly fish, and some eat sea mammals, turtles and other sharks.
Shark attacks are rare.
Sharks don’t have hard bones. They have cartilage. It is lighter than bones. They can bend their bodies.
Sharks have 6 senses.
Sharks have very good smell. They can smell blood from animals one kilometer away.
Sharks move their head from side to side. This helps them see better.
Sharks can’t taste very well. They can turn their stomachs out of their mouths to get rid of things they can’t digest.
They can touch with the help of a lateral line on the side of the body.
Sharks have electroception, which is a sense that lets them detect electricity to find fish. It is the sixth sense. Sharks can sense the heartbeats of other animals in the water.
There are so many species. Great white, whale, basking, and hammerhead are some. There is a big one called Carcharodon megalodon. It is extinct.
They can breathe underwater. They have ram ventilation. That means they need to keep moving to breathe.
They come in different colors, shapes, and sizes.
They have streamlined bodies that let them move very fast in the water.
Shark livers are very large and help to float.
They have many fins of which are two are dorsal, anal (not in all species), one caudal, two pelvic and two pectorals.
The ocean needs sharks. They are good for the environment. They are so cool.
I was thrilled to read these because sharks are much maligned. Digging a little bit deeper I was shocked to learn that around 100 million sharks are killed every year. I knew that they were prized for their fins, which are used in Asian countries in a soup, but the sheer numbers that are being killed saddens me. It is unsustainable. And cruel. The fins are cut from the sharks and they are discarded back into the water while they are still alive.
But finning is not the only reason sharks are killed. They are also killed for their livers.
Could a COVID-19 vaccine result in the deaths of many sharks?
The short answer is “yes”.
Now, I have to qualify this answer with a couple of caveats. It depends on the type of vaccine that is approved. Most vaccines will not require adjuvants made from shark livers. In fact, none of the frontrunners do. And there are certainly workarounds that don’t require sharks to be killed in large numbers. I’ll get to that. But first the most mind-boggling question.
How are sharks involved in all of this?
Shark liver contain a compound called squalene that might be used as an adjuvant for some effective SARS-CoV-2 vaccines to prevent COVID-19. Adjuvants are substances that are added to vaccines to help boost the immune response. No one knows quite how adjuvants work, but scientists think that they draw immune cells to the site of the injection so a better response is produced.
Squalene is a hydrocarbon oil which occurs naturally. It is made by plants and is found in many types of food. It is also made by many animals. We make it too. In humans, squalene is a precursor for cholesterol and steroid hormones. Because squalene is biodegradable and natural, it is unlikely to cause an adverse reaction. And so, it has been used as part of many adjuvants that are needed with vaccines since the Nineties.
For example, squalene is a part of a vaccine adjuvant, which has been in use in a flu vaccine in European countries since 1997. Millions of doses of this vaccine have already been given.
I know what you’re thinking. If plants and animals produce squalene, why are sharks so vulnerable? It’s simply a matter of economics. Sharks have huge livers than can be up to 30% of their body weight. Deep-sea sharks that live under depths of 400 meters have livers with the highest concentration of squalene found in the natural world.
In sharks, the liver is the organ that stores lipids that serve as energy sources and a way to regulate buoyancy. In their case, certain kind of lipids (of which squalene is the most common) make up to 80% of the liver. Around 3,000 sharks are needed to get 1 ton of squalene.
No one is suggesting that people shouldn’t get vaccinated, but there are alternatives to animal squalene. And hopefully most approved vaccines won’t require squalene at all.
The larger point is that squalene isn’t just used in vaccines. It is also used in some face creams and lipstick because it is an oily moisturizer. Shark liver oil is also sold in capsule form as a health supplement.
Are these really necessary? The lesson here is we need to be more informed as consumers. There are alternatives to smearing shark liver oils on the face or swallowing them for good health.
My video pick for this week:
Why the massive Megalodon shark went extinct.
Megalodon was an awesome animal. And it was huge. This is a great explainer on why they’re not around anymore.
That’s it for this week. If you like this post, please share it.
Here’s the link to the Kindle version on Amazon.com.
Here’s the link to the hardcover version on Amazon’s Indian site.
Here’s an excerpt of the book in which I talk about how so many COVID-19 vaccines were developed so quickly (and why they’re not the same).
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Why shark names are such tongue twisters🤔?