Wendy Zuckerman

Yeah, the CDC sent this team over to help get the Americans back home.

But it quickly became clear that this ship gave scientists an unusual opportunity.

There were more than 3,000 passengers and crew on that ship with nothing to do but get tested for coronavirus and answer questions about their symptoms.

And that is what happened.

Basically, all the passengers on that ship were tested for coronavirus, whether they were sick or not, including Mark, who we heard from at the beginning of the show.

Now, it turned out that more than 700 people would be positive.

So how many of those had no symptoms?

But Mateus says that this 50%, it isn't ship shape.

And in fact, it can be deceiving.

So for example, Mateus says that people can start to feel sick after the test was done.

So they're not actually asymptomatic.

They're what's called pre-symptomatic.

This is a big issue with a lot of the studies that you might have heard about, including one out of Iceland that got a ton of attention.

The kind of testing that they're doing in these studies is seeing if someone has pieces of the virus in their body at the moment they're getting tested.

And the problem with this is that if you find bits of virus, you could be catching someone at the beginning or end of their illness.

You don't know.

And if you've got someone at the beginning, they could still go on to get symptoms later.

So that means you need to follow people after they've been tested to see if they eventually get sick.

And many studies, they don't do this.

But Mateus's team did.