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  • This episode of SciShow is supported by Brilliant.

  • Go to Brilliant.org/SciShow to check out their Knowledge and Uncertainty course.

  • [♪ INTRO]

  • This video was filmed on September 1st, 2020.

  • For the most up to date information we have on the COVID-19 pandemic,

  • please refer to the playlist linked in the description.

  • On August 11th, Vladimir Putin announced Russian health agencies had approved

  • the world's first vaccine for widespread use against COVID-19: Sputnik V.

  • Yes, that's really what they decided to call it.

  • And it's potentially really good news!

  • But, many experts are skeptical as to whether the vaccine actually works,

  • because it's been tested in a really weird way.

  • Vaccines are technically drugs, and get approved by regulatory drug agencies.

  • They're supposed to publicly prove themselves in a very specific set of scientific tests.

  • This is, in large part, why vaccines as a whole are so safe and effective.

  • But this is not what happened with this Russian vaccine.

  • Its developers haven't published any of the results from human tests.

  • And they claimed success even before starting

  • the kind of testing you need to see if a vaccine actually works.

  • Alright, so, to back up: drug trials in humans, also known as clinical trials,

  • are typically organized into four to five stages, or phases.

  • These can sometimes be combined, but they're usually discrete,

  • because each builds on the previous ones.

  • In the US, they are creatively named Phases 0, I, II, III, and IV.

  • But Phase IV actually happens after the drug hits the market,

  • so we're going to focus on Phases 0 through III here.

  • Phases 0 and I are generally short, small studies intended to establish that

  • the drug does the very basics of what it's supposed to do,

  • and doesn't cause tons of harm in the process.

  • Since these trials are usually the first time a drug has been given to people,

  • researchers are really watching out for negative side effects, or, in trial lingo: adverse events.

  • They also generally try to figure out what dose would be best.

  • For instance, a Chinese company called CanSino

  • began a Phase I trial for their COVID-19 vaccine on March 16th.

  • They gave 108 participants a low, medium, or high dose of the vaccine.

  • And while quite a few of those people had mild to moderate side effects

  • like fatigue and headaches, the vaccine appeared safe enough to use in people.

  • So, it moved to Phase II.

  • Here, scientists continue to look for adverse events and evaluate dosing.

  • And the question of whether the drug actually does anything becomes more prominent.

  • Participant numbers also typically go up.

  • Like, CanSino's Phase II tested two different doses against a placebo in about 500 people.

  • And, as hoped, vaccinated participants started producing antibodies

  • that can neutralize the virus, and had other promising immune responses as well.

  • Now, at this point, you might be wondering

  • how Sputnik V fared in its Phase I and II trials. And so is everyone.

  • Although two combined Phase I and II trials for it

  • are listed online ascomplete”, their results haven't been published.

  • So, everything we know comes from the Russian government and the researchers involved.

  • There's no public data about how the vaccine works, or how well those trials went.

  • But more to the point: even if they did go well,

  • positive Phase II results don't guarantee the vaccine works in the real world.

  • While things like antibody levels are associated with protection in animals,

  • immune reactions are complicated.

  • And Phase II trials don't actually test whether a vaccine prevents people from getting sick.

  • That doesn't happen until Phase III.

  • These trials are typically hundreds, thousands,

  • or even tens of thousands of participants larger.

  • That's in part because researchers want to see

  • if or how many people catch the disease after getting the vaccine.

  • So, they need lots of people, to make sure that a good number of them

  • are exposed to the virus in their daily lives.

  • And that can take a long time,

  • which is why Phase III trials usually take a year or years, start to finish.

  • Another reason for the big numbers at this phase is to spot rare and serious adverse events.

  • Even something that happens once in every ten thousand vaccinations

  • can be a big deal, since we may want to vaccinate hundreds of millions of people.

  • And these also can take some time to manifest.

  • So Phase III trials are really important, both as measures of how well a vaccine works

  • and how safe it really is, and their large numbers and longer time tables are key to all of that.

  • Now... when Putin made the announcement,

  • it wasn't clear if Russia was planning to start one of these trials.

  • Since then, other sources have said that the vaccine's approval is actually dependent on

  • positive Phase III results, and that those trials have started,

  • or will start soon?… in several countries; the details are still fuzzy.

  • Even if that's the case, though, government officials have also said that

  • they want to start administering this vaccine in October,

  • which wouldn't give those trials time to show anything.

  • That's why doctors and public health experts are so unnerved by how this is all playing out.

  • Now, Russia isn't the only one taking risks or skipping steps

  • in the hopes of delivering a vaccine as soon as possible.

  • Like, here in the US, a company called Moderna launched into Phase I and II trials

  • for their COVID-19 vaccine before completing pre-clinical trials in animals.

  • Then, they went into Phase III before finishing Phase II

  • or publishing the full results from Phase I.

  • Also, the pharmaceutical company Pfizer announced that

  • they may apply for FDA approval for their vaccine candidate in October,

  • even though it'll still be in Phase II and III trials.

  • And while it would be unprecedented for the FDA to grant them that approval,

  • this week, the FDA commissioner said the agency might consider

  • an emergency use authorization, if a company

  • submitted compelling paperwork before the end of clinical trials.

  • Which in another way, isn't that unusual;

  • we have emergency authorizations for other COVID-19 therapeutics in America.

  • And China has implemented their own version of

  • emergency vaccine authorization for their military and at-risk citizens,

  • even though their vaccines are still in clinical trials.

  • But that's not what Russia initially said they were doing,

  • and it's still not entirely clear what's going on.

  • They seem to be all in on this as yet unproven vaccine.

  • And that's a pretty risky bet, considering that more than a third of drugs

  • that do well in Phases I and II fail in Phase III.

  • It's possible, of course, that the gamble will pay off.

  • Sputnik V could be a safe and effective vaccine.

  • But, if the vaccine doesn't work, or worse, proves truly harmful,

  • it could hurt a lot of people, undermine control efforts,

  • and ruin everyone's trust in whatever vaccine or vaccines succeed it.

  • It would be amazing if this vaccine pans out.

  • But over the years, we've developed a very specific and rigorous method

  • to make sure any drug or vaccine is as effective and safe as possible.

  • And this one isn't following it.

  • So, at this point, all we can do is wait and see.

  • All this uncertainty surrounding, like, everything to do with this pandemic is hard.

  • Uncertainty is hard in general.

  • But you can become better at dealing with everything you don't know,

  • with a little help from today's sponsor, Brilliant.

  • Their Knowledge and Uncertainty course dives deep

  • into the math behind uncertainty so you can feel more confident

  • in the conclusions you draw from the flood of conflicting information.

  • And they have more than 60 other courses covering topics in science, engineering,

  • math, and computer science, so you can level up your other STEM skills, too.

  • And if you're one of the first 200 people to sign up at Brilliant.org/SciShow,

  • you'll get 20% off an annual Premium subscription.

  • So, check it out if you're interested. And thanks for watching SciShow!

  • [♪ OUTRO]

This episode of SciShow is supported by Brilliant.

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What's Up With That Russian Vaccine? | SciShow News

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    joey joey に公開 2021 年 06 月 04 日
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