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  • - [Mitchell] As Covid-19 spreads

  • from the coronavirus pandemic,

  • many are doing their part by social distancing

  • and self-isolating.

  • But as the virus and disease progress,

  • one big question on many people's minds is,

  • what can we expect with regards to a vaccine?

  • - So, there are a ton of fascinating things

  • happening right now and tireless research

  • looking into a vaccine.

  • But in order to understand it,

  • we must first talk about how vaccines work.

  • It was in the year 1796

  • that the first official vaccine was created

  • by Edward Jenner.

  • He took a bit of the cowpox virus

  • and injected it into a small boy.

  • He later was able to confirm

  • that that boy did not develop smallpox,

  • which was a related virus.

  • So, how exactly did this work?

  • Typically, when you get infected with a virus,

  • it begins taking over your cell's machinery

  • in order to make copies of itself.

  • But these actions eventually trigger an immune response.

  • Your body begins creating special cells

  • like macrophage, B cells and T cells,

  • that not only try and destroy the pathogen

  • but also store information about it.

  • What it looks like, the best way to defeat it, and more.

  • This part is specially important

  • because if the virus ever comes back again,

  • your body can be immediately prepared to attack it.

  • But the body takes time to do all of this,

  • and so, if a virus gets enough of a head start

  • or attacks somebody with a compromised immune system,

  • it can gain the upper hand,

  • leading to illness or death.

  • - This is where vaccines come in.

  • There are many different types,

  • but the goal of them all is

  • to prep and train your immune system

  • before you get an infection.

  • It's like a practice run.

  • That way, when your body is invaded by the real virus,

  • it has an advantage because it already knows

  • how to take down the invaders.

  • Most vaccines work by injecting some aspect of a virus

  • or bacteria into your bloodstream,

  • depending on what strain you're trying to protect against.

  • We're gonna focus on viruses today.

  • Once administered into the bloodstream,

  • even though it's not the real virus,

  • the body reacts as thought it's a real threat.

  • macrophages engulf the pieces,

  • allowing T cells to recognize and bind the foreign antigen,

  • causing them to replicate into all different kinds

  • of immune cells

  • and trigger something called memory cells.

  • These stick around even after the body is done fighting,

  • and it's these memory cells that allow for a quick response

  • if and when the real virus shows up.

  • - The effectiveness of vaccines have allowed us

  • to nearly eradicate diseases like measles,

  • until, of course, the recent vaccine hesitant movement

  • in which kind of came back.

  • Regardless, they are extremely powerful tools

  • to provide immunity to the individual

  • and to protect larger communities,

  • and, in our ever-connected world, all of humanity.

  • Now there is more than one type of vaccine.

  • Live attenuated vaccines like measles, mumps, and rubeola

  • introduce weaker or asymptomatic forms of the virus

  • into your body,

  • which are very effective but can't be given to people

  • with compromised immune systems.

  • Inactive vaccines like polio or hepatitis A

  • use dead pathogens that have been killed

  • by heat or chemicals.

  • These can be used on people

  • with already weakened immune systems.

  • However, they aren't great for long-lasting immunity

  • because they don't stimulate the real thing

  • quite as well as live attenuated vaccines

  • and often require several doses.

  • Subunit vaccines like hepatitis B or influenza

  • use a specific protein or carbohydrate from the pathogen

  • that will still trigger an immune response.

  • There are some other experimental DNA vaccines,

  • but perhaps the most relevant

  • is a promising new technique of vaccines

  • called mRNA vaccines,

  • which you may have heard about recently.

  • That's because they are currently in development

  • and have begun testing on humans

  • to potentially fight the spread of Covid-19.

  • - The private company Moderna has created a vaccine

  • called mRNA-1273

  • and has enlisted 45 healthy adults

  • to start receiving the vaccine.

  • This is unprecedented because they've skipped

  • the typical years of animal testing

  • and instead are doing it at the same time

  • as their human trials.

  • But experts believe they received permission

  • because they're not actually inserting

  • a modified virus into individuals,

  • but rather a sequence that codes

  • for the tiny protein spikes that are on the virus

  • that connect with human cells.

  • The hope is that this mRNA will get processed in your cells

  • and have them making the spike-like protein

  • that will be on the virus,

  • which would then trigger your immune system

  • to kick into action and ultimately have your body prepared

  • for when the real thing happens.

  • They were able to get ahead on building this thing

  • because of Chinese scientists

  • who sequenced the genetic material

  • of SARS-CoV-2,

  • the virus that causes Covid-19.

  • This information was publicly released in January

  • which has helped labs around the world

  • start to test and build out vaccines.

  • SARS-CoV-2 shares between 80 to 90%

  • of its genetic material with SARS,

  • the virus we know about from 2003.

  • Both consistent of a strip of ribonucleic acid

  • inside a spherical protein capsule

  • that is covered in spikes.

  • - This means that some of the vaccine information

  • is able to take up where the SARS vaccine left off,

  • and I know we have said

  • that they have already started to give this to humans

  • but this is only to test safety,

  • to make sure there's no negative effects,

  • and to see if it actually creates the antibodies.

  • Clinical trials usually take place in three phases,

  • and the first phase is to test for safety

  • and make sure there's no negative adverse effects.

  • The second phase is to test for efficacy,

  • and usually you give it to a larger amount of people

  • in a place where the disease has taken hold.

  • For example, they're doing it right now in Seattle.

  • The third phase is to continue this testing

  • in a larger expansion,

  • now looking at thousands of people.

  • If the vaccine does appear to be safe,

  • Moderna is gonna ask the FDA

  • to move on to the second phase

  • before the first phase has technically even finished.

  • You can start to imagine how long this is going to take.

  • As you give people these experimental vaccines,

  • you can't just then give them the virus and the disease.

  • You have to let them go out and live their lives

  • and see what happens when they may be contracted,

  • when they maybe don't.

  • You have to look at tested individuals

  • next to control groups, people who didn't get the vaccine,

  • and start to see what happens.

  • Does it even work, does it make people unhealthy,

  • does it do nothing?

  • For example, in 2004, when a SARS vaccine was being tested,

  • vaccinated ferrets developed

  • damaging inflammation in their lungs

  • after being infected with the virus.

  • Approval can be accelerated

  • if regulators have approved similar products before,

  • which is how the flu vaccine is so well designed

  • and modulated to be updated yearly.

  • - But the SARS-CoV-2 virus

  • is a novel pathogen in humans,

  • which means many of the technologies

  • that are being used to develop the vaccine

  • are relatively untested.