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  • For most illnesses,

  • a vaccine is an almost guaranteed lifeline.

  • But influenza is different.

  • We have a very good measles vaccine.

  • We have a very good rubella vaccine,

  • very good mumps vaccine.

  • All of these viruses in the population haven't changed

  • over the last 50, 60, 70 years.

  • In contrast, influenza changes every year.

  • The World Health Organization

  • estimates that influenza infects 1 billion of us every year;

  • causing up to 650,000 deaths worldwide.

  • Vaccines are critical,

  • but they're only around 50% effective

  • because they don't fight every strain of flu.

  • So scientists around the world are searching for a shot

  • that fights different strains of the virus

  • including some that might not even exist yet.

  • It's really very exciting,

  • because you know that you're working for something good

  • that may change the whole world

  • and the health of many people.

  • This breakthrough will give us lasting protection

  • against influenza, but it might also help us understand

  • how we get there with other viruses too.

  • Difficulty breathing, highly contagious,

  • returning year after year.

  • Hippocrates first described influenza in 412 BC.

  • Since then, the virus has caused annual epidemics.

  • Most notably the Spanish flu in 1918

  • that killed an estimated 50 to 100 million people worldwide

  • and changed the world in ways

  • that seem all too familiar today.

  • 1918, when the influenza H1N1 showed up,

  • was during a period of a lot of problems

  • in the United States at the time.

  • World War I was ongoing at that time,

  • there was a lot of movement from rural areas into cities.

  • So at the time we didn't even know it was a virus.

  • Viruses were kinda still being figured out at the time.

  • So it really was not until the 1930s,

  • that we knew the cause of the 1918 pandemic

  • and then subsequently the seasonal epidemics

  • that we would have every winter

  • that they realized that was actually due to a virus.

  • And so from the '30s,

  • it wasn't really until the late 1940s and 1950s

  • that actual vaccines were being used more regularly.

  • Even though there are just three basic types of flu,

  • A, B and C; type A which is the most dangerous for humans,

  • has a surface covered in two main proteins, H and N.

  • There are 18 different types of H protein

  • and 11 types of N protein.

  • And they combine to create up to 198 influenza subtypes

  • including ones like H3N2 and H1N1.

  • The influenza virus is constantly changing.

  • And so if you look at a virus,

  • on the inside of the virus are the genes,

  • and genes are just the recipe,

  • the instructions for making more copies of itself.

  • So if somebody sneezes or coughs,

  • and you happen to breathe that in,

  • those viruses that are in those respiratory droplets

  • go to the back of your throat

  • they grab on to the respiratory cells that are there.

  • They push themselves into the cells

  • and then release those genes that are in there.

  • Those genes, it's not one long string of instructions,

  • it's eight separate strings of instruction.

  • And so there's so much opportunity for that virus to mess up

  • in terms of making copies of itself.

  • It's not a very good editor.

  • It really doesn't have good quality control.

  • In one way, that's bad for the virus

  • beause it makes copies of itself that may not even live on,

  • they don't even reproduce.

  • But it also means that it can find ways

  • to get around your own immunity,

  • and ways to get around vaccines that are being used.

  • to get around antiviral drugs as well.

  • This genetic shape-shifting,

  • is known as antigenic drift.

  • And means that our body can't always recognize the virus,

  • even if we've caught it or been vaccinated before.

  • But scientists at pharmaceutical company BiondVax,

  • have worked for almost three decades creating a vaccine

  • which targets parts of the virus that don't change.

  • All influenza virus are different in their appearance

  • but they are still considered as influenza

  • because they have a lot in common.

  • And what the immune system wants to do it,

  • they want to recognize the virus and to attack it

  • when it enters the body.

  • So we have to teach the immune system

  • how the virus looks like.

  • So what we thought will be more effective

  • and to have a universal vaccine,

  • is to show the immune system and teach it

  • to recognize the conserved and common denominator

  • of all influenza viruses.

  • So we constructed a vaccine, it is called M-001.

  • It contains nine such conserved regions

  • from the influenza virus.

  • Variations between influenza viruses,

  • usually happen on the surface.

  • But dig a little deeper,

  • and there are similarities in its peptides;

  • short strings of amino acids

  • that are responsible for how the virus functions.

  • M-001 is made up of nine different peptides

  • that our immune system can learn to recognize

  • and fight off in the future.

  • One of the peptides that we selected in our vaccine

  • is very close to the point where the virus

  • is entering the cells.

  • So it's like a key and the lock.

  • Where the key is on the side of the virus,

  • and the lock is the entrance to our cells.

  • And if the virus wants to enter the cell

  • and cause the disease, it enter its key into the lock,

  • opens it, and the disease starts to develop.

  • So by our vaccine, we block this key

  • and the virus cannot anymore enter into the cell

  • and we prevent the disease.

  • So M-001 is in phase three clinical trials.

  • Are you feeling nervous about the results?

  • Of course, I'm worried all the time.

  • I hardly breathe

  • until we get the outcomes

  • of our pivotal phase three trial

  • which is a trial was over 12,000 participants

  • that was conducted in Europe.

  • In this trial, we injected half of the participants

  • with our vaccine,

  • and the other half received placebo, which was a saline.

  • And at the end of the trial,

  • which means at the end of this month,

  • we'll know how many participants

  • were ill in the experimental group

  • that was immunized with our vaccine, and how many were ill

  • in the control group that actually was not immunized.

  • And if the difference would be high enough,

  • then our vaccine works and then we're happy.

  • We will know if it is safe,

  • if it is protective against influenza.

  • A universal vaccine, like M-001,

  • would radically change the way we make our flu shots.

  • Currently, for Northern Hemisphere vaccines,

  • every February WHO picks four strains of influenza

  • which scientists predict

  • will most likely be circulating in October,

  • the start of the flu season.

  • This vaccine recipe is sent out to manufacturers

  • and the majority of vaccines

  • are made just like back in the 40s,

  • by injecting the vaccine virus into fertilized eggs.

  • It takes at least six months

  • to produce the high quantities we need.

  • So we have to really base

  • on what happened two months before February,

  • but we are not really good at that, unfortunately.

  • Dr. Peter Palese is a microbiologist,

  • who built the first genetic map of the influenza virus

  • back in the '70s.

  • The yearly influenza vaccine,

  • I think is underappreciated, underutilized.

  • So I think there is a benefit in taking the vaccine,

  • because even if you get the flu, it was a failure

  • but your disease morbidity is much lower.

  • Clearly, I think I want to encourage your listeners

  • to take the current vaccine,

  • the current influenza virus vaccine,

  • as an insurance against whatever might happen, yeah.

  • So it is a very safe vaccine.

  • I think it is a very good vaccine.

  • Having said that, if we want to make a better vaccine,

  • we have to show that it is at least

  • as good as the current vaccine.

  • But also that it really preempts

  • or knows what the other strains in year three,

  • four or five from now, will be.

  • And also the potential new pandemic strains.

  • Dr. Palese's team is also part of the race

  • to create a universal vaccine.

  • Like BiondVax, they're using an area of influenza

  • that that doesn't mutate.

  • The stem of the H protein on the surface of the virus.

  • We are redirecting the immune system

  • towards these conserved regions.

  • And I have to say, I can protect any animal,

  • whether it's a mouse, whether it's a ferret,

  • whether it's a guinea pig against any strain.

  • So using these constructs

  • which present the conserved domain of the virus,

  • it works beautifully in animals.

  • But remember, mice are not man, ferrets are not humans.

  • I think we make progress, but it is still not there.

  • And I can't promise you that it will be two years

  • or three years; we cannot really predict

  • how long it will take

  • that we will have such a universal influenza virus vaccine.

  • With disappointing results

  • in the M-001 phase three trials,

  • the wait will be longer than some had hoped.

  • But the research and time that's been invested

  • isn't wasted, far from it.

  • Could the work we're doing

  • to find a universal flu vaccine help in the way

  • that we tackle viruses like Covid-19?

  • Absolutely the other way around too.

  • And so the work that now with significant resources

  • and speed being put into Covid right now,

  • could have a significant impact on flu vaccine choices.

  • If you have a system in place

  • where you can make those kinds of vaccines fast,

  • as soon as you see an emerging, a pandemic influenza,

  • you can start making vaccine immediately,

  • so faster vaccines.

  • And so I think we'll learn a lot about that

  • with the Covid vaccines as well.

  • So all of that together, we would love to see

  • what we're learning with Covid, be applied to flu.

  • Because what we're doing right now with COVID

  • is highly informed by what we were doing

  • with flu previously.

  • What would be the next steps

  • if we got a universal vaccine?

  • What would be wonderful, is to get to that place

  • where flu vaccines aren't something

  • that are just for middle and higher income countries.

  • That low and middle income countries globally

  • have a significant impact of flu every year.

  • But a program to vaccinate children and adults every year

  • in a country with billions of people,

  • is really complicated and can be pretty expensive.

  • Coming up with a simple solution

  • that can be rolled out in a programmatic way

  • where it's cost effective for that country to do it,

  • would have a significant impact

  • for a better functioning country.

For most illnesses,

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Is a Universal Flu Shot Possible?

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    joey joey に公開 2021 年 05 月 23 日
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