are nearing the final stretch.

But health experts say vaccines are just one piece

of a larger puzzle in fighting the deadly disease

and getting us back to normal.

The other big piece are effective treatments

for those who are a%lready sick.

- Not everybody mounts a good immune response,

in particular immunosuppress patients are well-known

to not to respond well to vaccines.

So we are gonna need to have therapies

for those who are not vaccinated

and for those who don't make a good immune response.

- [Narrator] Right now, there are three main categories

of COVID-19 treatments: antibody therapies,

immunomodulators, and antivirals.

Antibody therapies leverage antibodies, like these,

that the body naturally produces

after recovering from a disease.

To ward off infection, they attach to proteins

on the viruses surface.

That prevents it from infiltrating cells.

Different types of antibodies target

different parts of the virus.

They circulate in the yellowish liquid part of blood

known as plasma.

That's where the treatment comes in.

- You can take that liquid and give it to a person

who's sick or to prevent disease.

So it is the transfer of immunity

from a person who's made it to a person who's susceptible.

- [Narrator] When given to sick patients,

convalescent plasma can potentially boost

a person's immune response to the virus,

but just for a few weeks.

- We always pull it out during a pandemic.

We did this for 2009 H1N1, obviously for things such as

Ebola virus disease in Africa.

- [[Narrator] Because it's relatively easy to produce

compared to vaccines and other drugs,

experts think it could possibly be used both as a treatment

and as a preventative medicine against COVID-19.

- It's based on the same principle

of if you have a protective antibody,

passive transfer of that could provide not only protection

prophylactically but also treatment.

- [Narrator] Plasma is widely thought to be safe,

and in August the FDA authorized using it

to treat patients hospitalized with COVID-19.

But its effectiveness is still being studied.

- Convalescent plasma is a little bit of a,

it's a mixed bag.

We don't actually know the titers of the patients

who have survived and done well after COVID.

- [Narrator] Titers are a measurement of how many antibodies

are in a person's blood.

Typically, the more antibodies a person has,

the better chance they have at fighting an infection.

This means that not all plasma is created equal.

The amount and quality of antibodies it contains can vary.

That impacts how effective the treatment can be.

- Getting with convalescent plasma right now

is a bit of an unknown.

- [Narrator] To overcome this,

scientists use plasma as a blueprint

to build a more potent drug known as monoclonal antibodies.

They do this by homing in on specific antibodies

that do the best job in stopping the virus.

- We screen these huge panels of antibodies

through many in vitro assays to select the best antibiotics

that block the ability of the virus to get inside cells

and infect them.

- [Narrator] Once they're identified,

scientists can mass produce them

in facilities that resemble breweries

and pack them into drugs that act as a targeted attack

against the virus.

- You're growing these cells in bioreactors,

which are huge steel tanks,

and then as the cells grow, they are pumping out antibody.

You are concentrating that, and in purified form,

this is what you are administering to patients.

- [Narrator] Both Regeneron and competitor Eli Lilly

have been racing to bring monoclonal antibody drugs

to market for COVID-19.

The companies are testing drugs that contain one

or two types of antibodies,

and researchers say they could have benefits

over plasma-based treatments.

- Monoclonal antibody preparations are consistent.

They are consistent from patient to patient.

They can be standardized,

and they are hopefully easier to use than plasma

because of its properties.

- [Narrator] Each of the companies has released

encouraging data from early stage clinical trials

showing their drugs help reduce coronavirus levels

and improved symptoms in non-hospitalized patients.

But both drug makers had to pause their studies

in hospitalized patients,

and the Lilly study was halted

in this patient population altogether

because they didn't see a benefit.

Early data among less severe patients though looks promising

for both drugs.

In October, President Trump was given

Regeneron's antibody cocktail

as part of his COVID-19 treatment.

The president said the drug was key to his recovery,

but it's unclear how beneficial the drug actually was.

- I just wanna say we have Regeneron.

We have a very similar drug from Eli Lilly.

And they're coming out and we're trying to get them

on an emergency basis.

- [Narrator] Both Regeneron and Lilly have asked the FDA

to authorize emergency use of their treatments.

- We have committed to manufacturing about 300,000 dose

of these antibodies by the end of this year,

And we have also partnered with those

so that we can scale up and produce

about 2 million dose of these antibodies

to be available annually for worldwide use.

- [Narrator] But physicians have expressed concerns

about these new drugs.

- This isn't the type of drug that is always able

to be scaled, that can be made available to everyone rapidly

and also is a low cost

- [Narrator] Experts say both plasma

and monoclonal antibody treatments could help

not just COVID-19 patients

but also help prevent infection in healthy people.

To treat patients,

doctors have also been using immunomodulators.

These drugs suppress the immune system

and ensuing inflammation in the sickest

of COVID-19 patients.

That's important because this inflammation can be deadly.

One of those drugs is the steroid Dexamethasone.

Researchers have found that it improves survival

when given to severely ill patients.

The other treatment being used to fight COVID-19

is the antiviral drug Remdesivir.

This was another drug the president was given

at Walter Reed Hospital.

- So we really try to give Remdesivir as soon as somebody

may be admitted to the hospital.

We wanna give it as early as possible.

We know from Tamiflu and the flu

and all those kinds of different drugs

that giving antivirals sooner rather than later

is really important.

- [Narrator] Here's how it stops the coronavirus.

When a virus infects a cell,

it uses the cell's machinery to build more viruses.

It does that by making copies of its RNA.

That's the genetic material

that contains instructions for replication.

Remdesivir is designed to infiltrate these instructions

by inserting itself into copies of the viruses genetic code.

This interrupts the replication process

and acts as a kill switch for the virus.

Promising clinical trials led to the drug being approved

for emergency use in May,

but more recent studies have produced conflicting results

about its ability to speed up recovery

and curve death in COVID-19 patients.

The Department of Health and Human Services

allowed drug maker Gilead to market the drug

directly to hospitals in October.

And the CEO said he was confident in being able to deliver

the drug to the patients who need it.

- We now have enough supply of this medicine for patients

in the United States and globally by the end of this month.

- [Narrator] There's been tremendous progress

in treating COVID-19 but health experts caution

that there is still more work to be done

to see just how effective these treatments are.