Name: Could Antiviral Pills Change the Course of the Pandemic?
Uploaded: undefined
Duration: undefined

NOVA

Carlisle Companies

Viking

NOVA Science Trust Logo

Here's how Covid-19 antiviral pills from Pfizer and Merck and Ridgeback work, how effective they are, and how they might change the course of the pandemic.

The FDA authorized use of the first antiviral pills to treat COVID-19 at home.

Here's how Covid-19 antiviral pills from Pfizer and Merck and Ridgeback work, how effective they are, and how they might change the course of the pandemic.

Could Antiviral Pills Change the Course of the Pandemic?

The FDA authorized use of the first antiviral pills to treat COVID-19 at home.

Body & Brain

Could Antiviral Pills Change the Course of the Pandemic?Published: January 6, 2022Narrator: The FDA authorized use of the first antiviral pills to treat COVID-19 at home. Paxlovid, by Pfizer, is approved for use in high-risk patients 12 years and older. Clinical trials by Pfizer, found that Paxlovid reduces the risk of hospitalization or death by 89 percent and will likely work against the Omicron variant. Antiviral pills, could help to reduce the number of hospitalizations.Celine Gounder: If you do end up with an infection, this is your backup plan, to shorten the duration of infection and prevent you from ending up in the hospital.Kathie Seley-Radtke: They're easy to make. They can be shipped all over the world. They don't need to be administered by a doctor, you know, in a hospital setting. And so I think it's really critical because, you know, it's almost like a one two punch.Narrator: The day after Paxlovid was approved, the FDA approved use of another antiviral pill, Molnupiravir, by Merck and Ridgeback, for high-risk patients 18 and older when other approved treatments are not accessible or appropriate.So how do they work? What do we know about their effectiveness? And what does this mean for the course of the pandemic?Monica Gandhi: So the holy grail of what we want for an outpatient therapeutic is to give a pill, say, five days, twice a day, which is what these both pills are, and that they are directed specifically against enzymes in the virus, that and inhibit viral replication. That's what's coming.It's going to massively change the pandemic, in my opinion.Narrator: The emergence of variants of concern like omicron underscore that the more the virus spreads, the more it can continue to mutate, potentially evading vaccines potentially beyond what the vaccines can recognize.The manufacturers of the new antivirals say the treatments will likely protect against variants of concern in part because of how they work. Variants often emerge with changes on what's known as the spike protein—the part of the virus that opens our cells up to infection. But the pills are designed to stop new virus from being made—no matter what the spike protein looks like.Gandhi: They will still work against variants because these work to stop the virus from being replicated.Narrator: The first fully approved antiviral treatment for COVID-19 was Remdesivir, which is administered in hospital health care settings, through injection.It works by interrupting viral replication—much like the new pills. A recent study found that Remdesivir reduced hospitalization in high risk patients by 87 percent when given early. But other studies—including one from the World Health Organization—found the drug was less effective in improving outcomes.Gandhi: It's OK effective, but it's not profoundly effective in the hospital because by the time you've gotten that sick, unfortunately your virus has actually come down, but your inflammation in your lungs is what's hurting you the most.Narrator: The two COVID antiviral pills, Paxlovid and Molnupiravir, can be taken at home, twice daily over the course of 5 days. Both pills aim to stop the virus from replicating but in different ways.Viruses work by invading cells and taking over their machinery, tricking them into constructing many copies of the virus.Gandhi: COVID is an RNA virus, SARS-CoV-2. It comes into the cell and then it's RNA needs to be made into new RNA strands. And then each of those RNA strands are put into a new viral particle.Narrator: RNA Is made of building blocks called bases known by their initials: "A," "U," "G," and "C". Molnupiravir looks a bit like a "C" or a "U."So when the cell tries to build more virus RNA, it mistakenly uses Molnupiravir instead of the regular ingredients.Seley-Radtke: So you get a mismatch of of what the normal base pairing would be. And this the base pairing is important because that's the actual genetic information that is is going on to form the next, you know, to form the virus particle. So what happens is each round of this process adds more and more and more wrong bases. And so you get this mis-pairing and it's it leads to what's known as error catastrophe.Narrator: Through this faulty base pairing, Molnupiravir continually introduces mutations until eventually there are so many errors in the viral code that newly minted viral particles aren't functional.Seley-Radtke: It's got so many errors along that strand that it's like, wait a second. No, no, no, no, no. You're not making new viral particles. You’re stopping that process of viral replication.Narrator: Paxlovid, Pfizer’s antiviral pill, stops the creation of new viral particles after the cell has already used the virus’ rna to build a protein.Gandhi: RNA is translated into a big, long protein. That's useless. We don't need a big long protein. We need that big protein to be cut up into smaller proteins to be packaged with the RNA into a new nice viral particle.Narrator: The cutting up is usually done by an enzyme called a protease - so that the cell can assemble the virus from smaller pieces.But this is where Paxlovid comes in.Gandhi: Paxlovid is a protease inhibitor that blocks that protease and blocks that cutting up of that big poly protein into smaller proteins and inhibits viral replication.Narrator: Paxlovid is actually a combination of two things that work together- the protease inhibitor and a drug called Ritonavir that’s used in HIV treatment.Gandhi: In the same way this Paxlovid product, it actually needs to get to higher levels or it doesn't work. And what Ritonavir is doing in this case is boosting up its levels and making it high enough levels to work in the human body.Narrator: Paxlovid can affect how some medications are metabolized by the body. Molnupiravir raises different concerns. Because it causes mutations in the virus’ RNA through that faulty base pairing, there is some concern that it could also interact with human genetic material.Seley-Radtke: The concern has been for this class of compounds for many years that it would also hit our nucleic acids, our DNA, our RNA, and that that would cause toxicity and potentially genetic problems.Merck is saying that they have not seen that so far. But I don't think we've really seen a lot of the clinical data published in peer reviewed journals yet. So it's really hard to say what's what's really happening.Narrator: Clinical trials by the manufacturers found that both treatments reduce hospitalization or death. Molnupiravir by 30 percent and Paxlovid by 89 percent.Gandhi: Molnupiravir was not developed specifically for SARS-CoV-2. It was actually developed before to inhibit other RNA viruses and was being considered for Ebola, for example and it doesn't actually work as well, at least in the clinical trial. Paxlovid which of course, is the one that's a protease inhibitor, so it specifically was designed from scratch just for COVID. Designed, targeted, against the protease of COVID.Narrator: Experts say these pills have potential but emphasize that they would need to be taken soon after a person is infected.Gounder: If you think about, you know, if you call your primary care doctor's office and you ask for an appointment, very often you're not able to get an appointment within a day or two or three. And so if you're not able to get tested to get that prescription, to get your hands on that pill really within a day or two, the impact of these medications is going to be much less than we would have hoped.Seley-Radtke: I do think, however, that ultimately it's not going to just be one pill. I mean, we we need combination drugs, drug cocktails. This is how we, you know, we have conquered HIV to the point where people live their whole lives with undetectable levels of the virus because you're giving people combinations of two, three and four drugs that work by different mechanisms and therefore more fully shut down the virus replication. And that's really how you, you, you know, really take down the virus and keep it from developing resistance.Narrator: More than a year after COVID-vaccines first became available, outside of clinical trials, the emergence of antiviral pills could be a turning point for how COVID-19 is treated.

United States

Northern Mariana Islands

Puerto Rico

American Samoa

Guam

U.S. Virgin Islands

U.S. Minor Outlying Islands

US & Territories

Colossal explosions shake a remote corner of the Siberian tundra, leaving behind massive craters. In Alaska, a huge lake erupts with bubbles of inflammable gas. Scientists are discovering that these mystifying phenomena add up to a ticking time bomb, as long-frozen permafrost melts and releases vast amounts of methane, a potent greenhouse gas. What are the implications of these dramatic developments in the Arctic? Scientists and local communities alike are struggling to grasp the scale of the methane threat and what it means for our climate future. (Premiered February 2, 2022)

In the Arctic, enormous releases of methane, a potent greenhouse gas, threaten the climate.

Arctic Sinkholes

The top half of Jupiter in blue and green against a night sky

A composite image of Jupiter using images captured by the James Webb Space Telescope. Image Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Judy Schmidt.

Explore the cosmos, delve into ancient history, and follow an extreme rescue with NOVA’s most-watched documentaries released in 2022.

NOVA’s most popular science documentaries of 2022

Four bright orange loops brand off of a dark blue blob

A transmission electron micrograph of HIV-1 virus particles (orange) replicating from the plasma membrane of an infected H9 T cell. Credit: NIAID, Flickr

Scientists have cured a handful of people of HIV by piggybacking on treatments they received for blood cancer. But does that bring a widespread cure any closer?

Could Antiviral Pills Change the Course of the Pandemic?

Support Provided By

Explore More

New COVID-19 Variants Spread More Easily

Pfizer and Moderna Covid vaccines 95% effective in clinical trials

How Long Does Covid-19 Immunity Last?

Transcript

Credits

Support Provided By

Explore More

New COVID-19 Variants Spread More Easily

Pfizer and Moderna Covid vaccines 95% effective in clinical trials

How Long Does Covid-19 Immunity Last?