- [Narrator] This massive
metropolis in the center of China
is at the heart of a virus
outbreak that has gone global.
The first death from the new
coronavirus outside of China.
- The cruise ship, the Diamond Princess
remains quarantined in Yokohama.
- [Reporter] More than 71,000
people have been infected
around the world.
- [Narrator] In February,
Chinese officials
and state media touted
a drop in the number
of daily new confirmed cases.
- [Narrator] But only hours later,
local authorities released
data showing a dramatic jump,
partially due to a shift
in the way new cases
were diagnosed and confirmed.
While the authorities said the
goal behind the new criteria
was to let more patients
receive better treatment,
this raised concerns that
the scale of the outbreak
has been larger than Chinese
data had earlier suggested.
- We thought there was better
transparency coming out
of China but it doesn't appear to be.
- [Narrator] In response to the criticism,
Beijing said it has been active and open
toward cooperation with
International experts.
To independently assess
the scale of the disease,
groups of scientists around the world
have been using mathematical modeling
and their estimates so far exceed
the officially reported numbers.
The new virus was first
detected in December
and by mid-January, the number of cases
was just over 40
but epidemiologists
across the world thought
that something wasn't right
when three cases were
confirmed outside of China.
- How could we have three
or seven exported cases
when there seemed to be
relatively small numbers?
- [Narrator] Christl
Donnelly and her colleagues
at the Imperial College London looked
at the number of cases outside China
which they call exported
to calculate the scale of the outbreak.
- Wuhan's a big city.
It has 19 million people
in the metropolitan area
and it has an International
airport and it's interconnected.
So there're flights and people traveling
to lots of places.
- [Narrator] They used
similar mathematical modeling
developed during the
H1N1 influenza outbreak
in Mexico in 2009.
- If you look at the number of cases
that have been exported
and then there is a factor
which you can use to then
estimate the number of cases
that there were in the source region.
- [Narrator] Before the
virus shut down the city,
the international airport operated flights
to dozens of major cities worldwide
with more than 3,000 passengers traveling
through the airport every day.
The researchers also assumed
that 10 days likely passed
between a person getting infected
and the disease being detected.
- But you can get an idea
by looking at the number of flights
that came out, what's the population size?
How many international
departures do you have
on a given day?
- [Narrator] The Imperial
College researchers estimated
that over 1,700 people could
have been infected in Wuhan
by mid-January indicating a massive gap
between China's 41
confirmed cases reported
at that time and their estimates.
Other researchers did
similar calculations based
on the exported overseas cases
and with several other variables
and came to similar results.
In later reports, scientists
factored in new data
and their numbers were still much bigger
than Beijing's official
tally of confirmed cases.
These findings give a rough picture
and the margin of error remains high
in part because of other
factors like the fact
that human-to-human transmission
was confirmed overseas.
Many people in China have been critical
of how Beijing has dealt with the crisis
and have been skeptical
about the official data.
- [Narrator] Donnelly says
that the Imperial College's analysis
is not aimed at criticizing
Beijing's efforts
but trying to look at what was going on
and what might be expected from the virus.
She says that there
are a myriad of reasons
why China's figures might
not reflect reality.
- It's difficult for any country,
if a new disease starts in your country,
there's a lot to be
identified to begin with
so when you first start,
you really don't know
what the potential is.
- [Narrator] What makes it even harder
to diagnose the coronavirus
is that people infected
may show very mild symptoms
like fever and coughing
that are also common in
other types of infections.
In an effort to battle the virus,
Beijing has spent about $800 million,
deployed thousands of medical staff
and built two field hospitals in days.
- China is doing many good things
that's slowing the virus
and this has to be recognized.
- [Narrator] While the WHO
repeatedly praised China,
other public health experts
have been more critical.
It took the agency nearly two weeks
to get a go head from Beijing
to send a group of experts to China
to conduct joint research
with Chinese scientists.
Epidemiologists say they're still learning
about the new virus
and hope their research
will help officials in China
to put effective measures in
place to tackle the outbreak.
