Wouldn't it be great if there were a vaccine for, like, everything?

I mean, vaccines work wonders when your immune system needs to prepare for a virus or some other pathogen. But it's a shame there isn't a vaccine for, like, high cholesterol or substance abuse.

We humans have a lot of health problems that are not caused by viruses! Well, actually, it turns out that scientists are working on vaccines for all kinds of non-pathogen things – everything from smoking to Alzheimer's. So let’s learn about a few very surprising things that you might someday protect yourself from with a yearly jab. [♪ INTRO] So vaccines activate your immune system and give it like a running start to combating invaders.

They work by exposing your immune system to some sort of pathogen, or at least a part of that pathogen, so it can recognize that thing in the future and neutralize the threat. Which makes perfect sense for things like the flu or COVID, since we know that our immune systems are what’s fighting off infectious invaders. And that’s what makes it so wild we’re using them to fight stuff that isn’t infectious, and so usually has nothing to do with your immune system.

Take, for example, high cholesterol. More than 80 million people in the U. S. have it, and it’s a major risk factor for things like heart disease.

High cholesterol can lead to fatty build-ups in the blood vessels, which clog up your arteries and make your heart work harder than it needs to. So, not great. And while diet is a factor, high cholesterol is also influenced by genetic factors, so it’s not enough to just skip the cheesy potatoes to avoid developing it.

Which is why there’s so much interest in developing any kinds of treatments and preventions for high cholesterol, including vaccines. Essentially, the problem with high cholesterol isn’t the cholesterol itself, but where it hangs out when there’s a lot of it. The blood vessels aren’t such a great choice since it can clog them up.

A better choice would be for that cholesterol to get inside our liver cells, because they can like do stuff with it. They turn excess LDL cholesterol– the bad kind – into bile to help breakdown fats that we eat. And it’s specifically LDL receptors that slurp up the LDL cholesterol from the bloodstream and deposit it into the liver cells.

However, there’s an enzyme called PCSK9 that decreases the number of those receptors on a cell’s surface, because it’s rude like that. More PCSK9 means fewer receptors, which means more cholesterol in the bloodstream, clogging up our blood vessels like paper towels in a toilet. So if we could make a vaccine that targets this enzyme, we could neutralize it before it destroys those receptors.

That would allow the liver to remove much more LDL cholesterol from the bloodstream and hopefully reduce blood clots. The FDA has already approved using monoclonal antibodies to target this enzyme, which are like, half of a vaccine. Monoclonal antibodies are considered passive immunization, meaning the injection delivers the antibodies that’ll get the job done, but they won’t actually teach your body how to make them.

Essentially it gives your body a fish, but it doesn’t teach it to fish. The true vaccines being developed use virus-like particles, that are kinda like a sheep in wolf’s clothing. They’re totally safe, but the body thinks that they are dangerous since they look like viruses, so it responds to that perceived threat.

And when we tack a piece of something else to that virus-like particle, the body starts attacking that, too. A study published in September of 2023 showed promising results when these virus-like particles were coupled with parts of the PCSK9 enzyme, which essentially tells the immune system to attack PCSK9. When this was administered to animals, antibodies against the enzyme increased significantly, leading to a 33% decrease in circulating PCSK9 enzyme.

So heart-health conscious lovers of cheese, rejoice! You may soon have a vaccine for high cholesterol. In terms of vaccine-treatable illnesses, substance abuse feels even wilder than that last one.

It’s a major public health problem that affects more than 20 million Americans. Substance abuse disorders are notoriously difficult to address, but finding effective treatments is crucial to improve people’s lives and safety. Traditional treatments generally include medications, replacement therapies, and counseling.

But it may not be long before immune-based options are available, too. These work by essentially making the immune system take out the substance before it gives the person any euphoric or pleasant side effects. That kinda takes the fun out of things, and renders it less addictive.

Vaccines that would neutralize nicotine have been making their way through clinical trials, and the early results look promising. So a vaccine against smoking may be the first on the market. And there are a bunch of other vaccines being studied in animals, too.

Since animal participants unfortunately cannot self-report their cravings for an addictive substance, these studies rely on either studying how often the animals self-administer the drugs, or doing physiological tests to monitor presence of the drug in their bodies. For instance, when monkeys that were dependent on heroin were given a vaccine against it, they significantly reduced how often they self-administered the drug, indicating that they weren’t feeling the cravings as strongly or as often. Another way to see if these vaccines work is by monitoring how much of the drug sticks around in their bodies after it’s been administered.

And studies of a cocaine vaccine in rodents showed that immunization reduced levels of the cocaine in their brain as soon as 30 seconds after injection, so some of these can act really fast. Rodent studies using a methamphetamine vaccine have also been well documented to reduce the drug-induced behavioral changes, which researchers hypothesize would remove the incentive to use the drug. With further development, these vaccines could make a real difference for people struggling with substance use disorders, and ultimately make quitting easier.

In recent years, there have been many attempts to find effective treatments for Alzheimer’s. But research suggests that one answer could be prevention, in the form of a vaccine. Senescence-associated glycoprotein, or SAGP for short, has been implicated in a number of age related diseases.

The protein is also over-expressed in the brain cells of people with Alzheimer’s. Because of this, researchers tested a vaccine against SAGP in mice with Alzheimer’s, and found that the vaccine not only reduced amyloid deposits and inflammation, but also led to normal performance in the maze tests six months post vaccination. The vaccine even restored anxiety in the mice!

Which sounds like a bad thing. But even though anxiety isn’t fun, having it indicates an awareness of your surroundings. In the later stages of Alzheimer’s it’s typical for this anxiety response to diminish as people lose that awareness.

This same diminishment was observed in the mice, but those who were vaccinated actually recovered this anxiety response, indicating a reversal in their mental decline. So this could even be a vaccine that helps before or after symptoms appear, which would be a pretty major step in treating Alzheimer’s. Now this one might sound a little weird, but the next big development in birth control might be vaccines against pregnancy.

Many current birth control options are hormone based, such as the pill, IUD, or implant. However, these can have undesired consequences, like irregular bleeding, nausea, and mood changes. And other options like barrier methods require consistent use every single time, and it only takes one slip-up to result in an unplanned pregnancy.

Which is where vaccines come in. The idea is to get your immune system to make antibodies against the hormone hCG, which is used by our bodies to facilitate conception. Without hCG, a pregnancy can’t continue, so if your immune system is trained to neutralize hCG when it sees it, that stops the pregnancy in its tracks.

This vaccine route would need the patient to go in for booster shots, because you have to make sure the immune system stays vigilant. That said, there are some nanoparticle versions of this vaccine that would be more of a slow-release variety, and thus, last longer. On the other hand, the required boosters highlight an upside of this vaccine: it’s a birth control method that’s temporary and reversible.

Right now in trials, it has about a 70% success rate, which is not ideal when there are other methods out there boasting 99% effectiveness. Still, if this one keeps improving, you might one day be able to say you’re literally immune to pregnancy. Millions of people, probably you, certainly me, experience some type of allergy, ranging from the neighbors fresh cut grass or latex to bees or cinnamon.

And depending on how severe these allergies are, you might even get allergy shots as a potential treatment. Those shots are basically the opposite of a vaccine, because rather than trying to incite your immune response, they’re trying to stop it. This is typically achieved through many tiny exposures to the allergen over a long period of time so that eventually the person's immune system becomes desensitized to the allergen and doesn’t overreact anymore.

So that makes sense. But one team of researchers had a crazy idea: what if instead of getting rid of the allergy immune response, we made the immune system outcompete itself? At some point when researching cat and peanut allergies, scientists realized that one immunoglobulin, IgE, was always around in high amounts during anaphylactic allergic reactions.

And a different immunoglobulin, IgG, was more abundant in people who didn’t have these severe allergic reactions. It seemed like the ratio of IgE to IgG was what determined whether the individual would have an allergic reaction or not, and if they did, how bad the reaction would be. The scientists predicted that if IgG was binding to the allergen and reacting to it, then IgE wouldn’t be able to bind and induce anaphylaxis.

So if the researchers could figure out a way to increase IgG, it would lead to less allergic reactions. So, they created a vaccine that purposefully elicited an increased IgG response when peanut allergens were present. This is another a virus-like particle vaccine, just like the one in the high cholesterol shots, and uses a virus that IgG responds to, sprinkled with some bits of peanut allergens.

They found that the vaccine was highly effective at reducing anaphylactic reactions in mice with peanut allergies. And testing showed that unvaccinated mice had higher levels of IgE than vaccinated mice, which showed that IgE does play some role in anaphylaxis. To confirm that the vaccine was protecting mice from anaphylaxis, the researchers then isolated the IgG from the vaccinated mice and put it into the non-vaccinated mice.

And when they did that, those mice were also protected from anaphylaxis. This confirmed that creating a vaccine to increase one immune response could reduce another, and effectively prevent anaphylaxis. So apparently fighting fire with fire actually works sometimes!

Vaccines are one of the most life-saving forms of healthcare out there. And as you have seen, they're no longer limited to just fighting pathogens. A future where there's a vaccine for nearly everything may not be far off.

It's pretty cool that researchers are taking this old dog of medicine and teaching it some very cool new tricks. Thanks for watching this episode of SciShow. We want to give a huge shout-out to our patrons on Patreon, because we couldn’t make these videos without you all.

Head over to Patreon.com/SciShow to check it out and learn more. Thank you to you for watching. Thanks to everybody for supporting it so that it’s free for everybody, and thanks to all the people who worked on this show, who I appreciate very much. [♪ OUTRO]