stopgap before we get a vaccine. The good news is that Remdesivir and steroids like

Dexamethasone are showing great promise. The search to find effective treatments has required

scientists to study lots of drugs - both new and existing - and some of them don't pan out.

First, let's get this out of the way. There's still no definitive evidence that

the antimalarial drug hydroxychloroquine is an effective treatment for COVID-19. But

other researchers are looking at convalescent plasma, which is antibody rich plasma taken

from those who have recovered. More research is needed to know how effective this option

truly is, but the FDA recently approved it for emergency use in hospitalized patients.

So, what makes remdesivir and dexamethasone so unique compared to other treatment options?

We spoke with Professor Horby, who is leading a team running the world's largest clinical

trial of covid-19 drugs, to find out more. There are a number of classes of drugs that can

be used in COVID-19. Remdesivir is in the antiviral class of drugs. These are drugs

that specifically target the SARS coronavirus itself. So they either bind to it and stop

it infecting cells, or they interfere with the replication cycle of the virus so that

it can't replicate itself, and so it starts to control the infection. Antivirals have

been around since the 1960's. The excitement surrounding Remdesivir is linked to a clinical

trial that wrapped up earlier this year. The results from a US trial showed that Remdesivir

reduced the time that patients spent in a hospital. It's the first drug that's an antiviral

drug that's shown a positive effect. Because of this drug's potential, the FDA recently

approved emergency use of remdesivir in adults and children in the hospital. But at this

time, it's still unclear whether the drug also significantly improves the chance of

survival. Here's where the steroid dexamethasone enters the picture. Dexamethasone is one of

the drugs that Professor Horby and his team are looking at during the UK's RECOVERY

trial. Dexamethasone is an anti-inflammatory drug, so it's part of a class of drugs that

dampen down the immune system that your body produces to help control the virus and control

the disease. After the several months long trial, Professor Horby and his team showed

that the drug worked best on patients with severe symptoms. For example, it cut the

risk of death by a third for patients on ventilators and by a fifth for those on oxygen. When the

results were first published, this was the only steroid that had been found to save lives.

But now there's evidence that other steroids, like hydrocortisone and methylprednisolone,

are also effective at reducing the risk of death. While all of this information is terrific

news, neither remdesivir nor steroids like dexamethasone are magic cure alls. Instead,

remdesivir stops the virus's replication mechanisms by mimicking a necessary component

of viral RNA. Essentially, the drug tricks an enzyme called RNA polymerase to incorporate

it into a growing RNA strand, which blocks the rest of the RNA from being replicated.

That creates a defective virus that can't replicate in other cells. You might be thinking

at this point, “Well great! If I get sick I can just use some of that, right?” Well,

not so fast. An antiviral drug like remdesivir must be able to kill a virus without killing

the human cell it occupies. And viruses are highly adaptive, able to mutate and develop

resistance to drugs that are trying to stop them. Which is why remdesivir is undergoing

additional human trials. Plus, blocking the virus from replicating itself is only one

hurdle. Sometimes your body in a sense overreacts, and you get too much inflammation, and it

starts to damage you. So you start to see damage to the lungs and other organs. Dexamethasone

is a corticosteroid, similar to the hormone cortisol that's produced by your adrenal

glands. It has anti-inflammatory effects which help to suppress your body's overreaction. But

that suppression walks a fine line. If taken too soon, these drugs may blunt the body's

natural defense system and reduce its ability to fight off the virus, thereby potentially

making the viral infection worse. Which begs the question: When should a patient get started

on this therapy? It's about a week into the illness that there's a divergence; people

either get better or they start to deteriorate and they start to get breathing difficulties

and end up in hospital. And if oxygen is needed, then that's typically when a steroid

like dexamethasone would be given to patients. In the UK, a treatment course with dexamethasone

is less than $10, it's just incredible and it's available in every country in the world. Remdesivir, on the other

hand, isn't as affordable. The price for a five day course can cost thousands of dollars,

depending on where you live and countries are already jostling each other to be first

in line. While mounting evidence continues to show that Remdesivir and Dexamethasone

are beneficial covid-19 treatments, there is always the possibility that other drug

treatments could work better. Other options,  like convalescent plasma and monoclonal antibodies,

which are basically molecules engineered to mimic the immune system's attack on cancer

cells, are still being explored. As all of these treatments undergo further scrutiny,

Professor Horby reiterated an important message for those who want to help speed up the process

for finding effective treatments. Being part of clinical trials is something that anybody

who's got COVID can do to make a really important contribution to the current pandemic, but

also to all future patients. If you want to know more about where we're at with a COVID-19

vaccine, check out our video here. And if there's another aspect of COVID-19 that

you'd like to see us cover, let us know in the comments below. Make sure to subscribe

to Seeker for all your viral news. Thanks for watching, and I'll see you next time.