I'm Carl Azuz with your Wednesday edition of our show.

By this time next week, at least 48 U.S. states will have relaxed some of their restrictions concerning coronavirus.

There's a lot of debate about this.

Many health officials say opening up the country too soon could lead to more cases and deaths from COVID-19.

Many business owners say keeping things closed could lead to a crash of the economy with more jobs lost.

Scientists around the world are racing to test and study different medications like the one we told you about last week that could help sick people recover faster.

Scientists around the world are racing to develop a coronavirus vaccine, though one of those could still be a year away or more.

And while coronavirus testing can help officials know who's sick now, antibody testing can help them know who's had this disease in the past.

This is crucial because doctors say that up to 50 percent of the people who have coronavirus have zero symptoms when they're tested.

So there could be a lot of people who have this disease or who have recovered from it without ever knowing they've contracted COVID-19 and they could have unknowingly spread it to others.

We've reported that the novel coronavirus was officially identified in Wuhan, China in mid-December of last year but U.S. intelligence agencies were tracking it there in November.

The first case in the United States was confirmed on January 21st, but more research is coming out that suggests it was spreading in America and other countries well before that.

So, antibody testing, when it works accurately, could supply some of the missing pieces of the coronavirus puzzle.

One of the ways our immune system protects us from viruses is through antibodies.

Antibodies are proteins in our blood that attach themselves to parts of viruses.

That limit's the infection and also alerts white blood cells to come in, attack, and eliminate the virus.

So in many cases, if the body encounters the same virus again, the immune system has left over antibodies that are taught and remember the previous infection.

These cells can either fight off the deadly virus directly, or they can produce more antibodies to help prevent the infection.

Researchers aren't entirely sure why this process works so well for some viruses but not others.

Our immune system seems to remember some viruses better than others.

A person is generally protected for life after one encounter with viruses like chicken pox or polio.

However, there are some viruses that our immune systems seem to easily forget.

Scientists have reported that immunity could be short lived after encounters with some common seasonal coronaviruses, which can cause the common cold.

That could help explain why we can repeatedly get sick with something as simple as a cold even if we think we've been exposed to cold viruses before.

We could be getting exposed to new strains as well.

And some viruses like the flu can mutate often, which means our old antibodies no longer work against these strains.

While most experts do believe that we're probably going to have some protection after being infected with the coronavirus, we're still not sure just how long that protection will be or how strong.

10 Second Trivia.

Where would you find the oldest underground railway in the world?

London, United Kingdom, Moscow, Russia, New York, New York or Budapest, Hungary.

A section of the London Underground dates back to 1863 making it the world's oldest underground railway.

When it was first built, workers dug large trenches through the streets, reinforced them, put roofs on them, and then rebuilt the street surface on top.

Did this impact traffic?

Yes, badly.

Did it work?

Yes, the first year was opened The London Underground carried more than nine million passengers when only a few 1,000,000 people lived in London at the time.

Building methods got better, though: as the subway expanded, large shields were developed and pushed through the soil beneath the city streets.

And one of these relics can be seen today.

All you got to do is look beneath the surface.

Most central London underground stations have some form of disused space, but some have far more than just something hold for pockets of history really tell a fascinating story.

[London Underground is the oldest subterranean railway network in the world.]

[Commuting up to five million passenger journeys a day.]

[But it's also a museum for disused stations and lines, left in a time capsule.]

We're actually kind of commuting in a living museum.

It feels very much like you're stepping from a normal day to day lives into something completely unusual.

[Siddy Holloway guides tours around these disused tunnels as part of the Transport Museum's "Hidden London" tours.]

This is the Moorgate Station that you might recognize and be very familiar with.

But where I'm about to take you now is somewhere that the public has not seen since 1924.

Moorgate was actually the first station that was extended on the first underground railway in the world, which was the Metropolitan Railway which opened in 1863.

And so, Moorgate is one of the oldest underground stations in London.

This station's quite extraordinary in the way it's evolved over 150 years since it opened.

What we're looking at here is a passageway built and opened in 1900 when the city and South London Railway extended from King William Street to Moorgate.

You can see there is original features all around us, in particular the white and black tiles, which are beautiful glass tiles.

And here we've got some incredible posters that have been left over since 1936.

For example, an advert for Lifebouy Soap, which is an incredibly popular soap back in the '30s and '40s and up until the '70s.

It really gives you a sense of kind of stepping back in time.

Here again you can see way out to the lift would have set there, but also quite interestingly, right next to it is an old no smoking sign that's sort of slowly been, kind of, peeled away.

This is actually from the second World War; it's not from 1924 when these passageways closed.

And that's because this whole area was used as a staff accommodation during the height of the Blitz.

[During the German bombing of London in 1940 and 1941 known as "The Blitz," more than 100,000 people were sheltering each night at 83 stations across the network.]

It definitely feels like, you know, you're somewhere you kind of shouldn't be when you come through here.

This is the only complete Greathead shield on the entire London Underground network, and this has been here since 1904 and will be here for the foreseeable future.

The whole of the London Underground would have been built with basically shields just like these.

The line was actually supposed to be extended further south to Loffbury.

It started excavating the extension, but they ran out of money and instead of dismantling the entire thing, they just decided to put concrete into the tunnel and seal it up that way.

Probably with the hopes that maybe one day they would be able to finish the job.

But they never did.

The London Underground is such a fundamental part of city life.

Everyone equates London with the Tube, but rare for us in terms of experiences is that we're actually able to go and see and feel and literally experience this closed off space.

[10 Out of 10]

The robotic dogs we've seen from Boston Dynamics aren't exactly the cuddly, furry sort you want to pick up and snuggle.

Then again, this ain't no therapy dog.

Its name is Spot.

It's not trained, but it is programmed.

Its job is to play a prerecorded message in a human voice to encourage people to practice social distancing.

Spot's cameras can also estimate how many people are hanging around.

This is a pilot program at a park in Singapore, and if it's successful more people at more parks could see more "Spots" in the days ahead.

Just the sight of that would make some people "scare-dy cats," and those who break the law could see Spot as man's best "fiend".

But, if you're not a cat person, you're not "dogged" by robots, and you're not afraid of a canine crime fighter who's a little "McGruff" around the edges, you won't mind walking with Spot as long as the project isn't "short circuited".

Peola High School is watching today from Peola, Washington.

It was great to see your comment at our YouTube channel.

I'm Carl Azuz, and CNN 10 will be "bark" tomorrow.