What we do (and don't) know about the coronavirus

What happens if you get infected with the coronavirus? Who's most at risk? How can you protect yourself? Public health expert David Heymann, who led the global response to the SARS outbreak in 2003, shares the latest findings about COVID-19 and what the future may hold.

[As of the morning February 27, 2020,

there were at least 82,000 confirmed
cases worldwide of the coronavirus

and 2,810 deaths from it.

TED invited Dr. David Heymann to share
the latest findings about the outbreak.]

[What happens if you get infected
with the coronavirus?]

This looks like a very mild disease,
like a common cold,

in the majority of people.

There are certain people who get infected
and have very serious illness;

among them are health workers.

It's a very serious infection in them,

as they get a higher dose
than normal people,

and at the same time,
they have no immunity.

So in the general population,

it's likely that the dose of virus
that you receive when you are infected

is much less than the dose
that a health worker would receive,

health workers having
more serious infections.

So your infection
would be less serious, hopefully.

So that leaves the elderly
and those with comorbidities

to really be the ones
that we have to make sure

are taken care of in hospitals.

[Who are the people who should be
most concerned about this?]

Well, the most concerned are people

who are, first of all,
in developing countries

and who don't have access
to good medical care

and may not have access
at all to a hospital,

should an epidemic occur in their country.

Those people would be at great risk,

especially the elderly.

Elderly in all populations are at risk,

but especially those
who can't get to oxygen.

In industrialized countries,

it's the very elderly
who have comorbidities,

who have diabetes,
who have other diseases,

who are at risk.

The general population
doesn't appear to be at great risk.

[What pre-existing medical conditions
put people at higher risk?]

First of all,

pulmonary disease existing
as a comorbidity is also important.

In general, the elderly
are at greater risk,

especially those over 70,

because their immune systems
are not as effective

as they might have once been,

and they are more
susceptible to infections.

In addition, in some instances in China,

there's been a coinfection with influenza

and at the same time,

there have been some
bacterial superinfections

on the pneumonias that are occurring.

[Where can we find
up-to-date information?]

The Center for Disease Control
in Atlanta keeps track

and has updates on a regular
basis on its website.

Also, the World Health
Organization in Geneva,

which is coordinating many
of the activities

going on internationally,

also has a website with daily updates.

It's our responsibility
to get that information as individuals,

so we understand

and can make sure that we can
contribute in our own way

to prevention of major spread.

[You led the global response
to the SARS outbreak in 2003.

How does this outbreak compare?]

That's the same problem
with all new infections.

This is an infection
that's coming to humans

who have never been exposed
to this virus before.

They don't have any antibody protection,

and it's not clear whether
their immune system

can handle this virus or not.

This is a virus that usually finds itself
in bats or in other animals,

and all of a sudden, it's in humans.

And humans just don't have
experience with this virus.

But gradually,

we are beginning to learn a lot,
as we did with SARS.

And you know, there are certainly
a larger number of deaths

than there were with SARS.

But when you divide that by a denominator
of persons who are infected,

there are many, many more persons infected
than there were with SARS.

The case fatality ratio,

that is the ratio of deaths
to the numbers of cases in SARS,

was about 10 percent.

With the current coronavirus, COVID-19,

it is two percent or probably less.

So it's a much less virulent virus,

but it's still a virus
that causes mortality,

and that's what we don't want
entering human populations.

[Have we responded adequately
at border crossings, such as airports?]

It's clearly understood
that airports or any land borders

cannot prevent a disease from entering.

People in the incubation period
can cross that border,

can enter countries

and can then infect others
when they become sick.

So borders are not a means of preventing
infections from entering a country

by checking temperatures.

Borders are important because
you can provide to people arriving

from areas that might be at risk
of having had infection,

provide them with an understanding,

either a printed understanding
or a verbal understanding,

of what the signs and symptoms are
of this infection,

and what they should do
if they feel that they might be infected.

[What's the timeline for a vaccine?]

Vaccines are under development right now,

there's a lot of research going on.

That research requires first
that the vaccine be developed,

then that it be studied for safety
and effectiveness in animals,

who are challenged with the virus
after they are vaccinated,

and then it must go into human studies.

The animal studies have not yet begun,

but will soon begin for certain vaccines.

And it's thought
that by the end of the year,

or early next year,

there may be some candidate vaccines

that can then be studied for licensing
by regulatory agencies.

So we're talking about at least a year
until there's vaccine available

that can be used in many populations.

[What questions about the outbreak
are still unanswered?]

It's clear we know how it transmits,

we don't know how easily
it transmits in humans,

in communities or in unenclosed areas.

We know, for example,

that in the enclosed area
of a cruise ship, it spread very easily.

We need to better understand

how it will spread once it gets
into more open areas

where people are exposed
to people who might be sick.

[What about the global response
could be improved?]

A major problem in the world today
is that we look at outbreaks

in developing countries

as something that we need to go and stop.

So when there's an outbreak of Ebola,

we think "How can we go
and stop this outbreak in the country?"

We don't think about
"How can we help that country

strengthen its capacity,

so that it can detect
and respond to infections?"

So we haven't invested enough

in helping countries develop
their core capacity in public health.

What we've done is invested
in many mechanisms globally,

which can provide support
to other countries

to go and help stop outbreaks.

But we want to see a world
where every country

can do its best to stop its own outbreaks.

[Will we see more emerging
disease outbreaks in the future?]

Today, there are over
seven billion people.

And when those people come into the world,

they demand more food,

they demand a whole series of things

and they live closer together.

In fact, we're an urban world,
where people live in urban areas.

And at the same time,
we're growing more animals,

and those animals are contributing
food to humans as well.

So what we see

is that that animal-human interface
is becoming closer and closer together.

And this intensive agriculture of animals

and this intensive increase
in human populations

living together on the same planet

is really a melting pot
where outbreaks can occur and do occur.

We will eventually have
more and more of these outbreaks.

So an emerging infection today
is just a warning

of what will happen in the future.

We have to make sure

that that technical
collaboration in the world

is there to work together

to make sure that we can understand
these outbreaks when they occur

and rapidly provide the information
necessary to control them.

[Is the worst behind us?]

I can't predict with accuracy.

So all I can say
is that we must all be prepared

for the worst-case scenario.

And at the same time,

learn how we can protect ourselves
and protect others

should we become a part of that epidemic.

[To learn more, visit:
Centers for Disease Control and Prevention

World Health Organization]