48 International The EconomistMarch 14th 2020
2 to co-operate with temperature checks be-
fore writing their names in visitors’ books.
They have also been ordered to minimise
contact and conversation with others in at-
tendance (including relatives of the de-
ceased). Across the country guests attend-
ing weddings must wear masks—as must
the happy couples, prompting many to
postpone their nuptials.
Restaurants and bars in Seoul were no-
ticeably quieter for a few days during the
peak of the government’s official social-
distancing campaign, which began in the
capital on March 2nd. But that has changed
in recent days. Seoul’s popular nightspots
are once again seeing long queues forming.
Trains are filling up and people are getting
laxer about wearing masks. The shift is
probably the result of officials saying that,
based on a steep fall in new cases in recent
days, they hope that the country has passed
the peak of its epidemic.
But on March 11th a new cluster of infec-
tions was discovered in a call centre in an
office building in Seoul that sits next to one
of the city’s busiest subway interchanges.
The outbreak may prompt people to stay at
home once again. And the government
may start enforcing its rules more strictly if
the voluntary approach proves inadequate.
On March 11th Park Won-soon, the mayor of
Seoul, said that he may consider forcing
call centres to shut down if they do not fol-
low recommendations to keep their em-
ployees at a distance from each other.
As countries employ varying intensities
of measures to battle their covid-19 epi-
demics, it should become clearer which
work best—and whether the most drastic
are the most effective. Gabriel Leung, an
epidemiologist from Hong Kong Universi-
ty who was part of a World Health Organisa-
tion team that examined China’s efforts to
contain its epidemic, says nobody knows
yet what combination of controls works
best against covid-19. “Do you need to do
everything that the Chinese have done to
control it?” he says, or is it enough to copy
only certain elements. “That”, says Mr
Leung, “is really the big question.” 7Heading in the same direction
Covid-19cases,2020,logscaleSource:JohnsHopkinsCSSE1001,00010,00051 10 15 18
Days since 100th caseItaly France Germany
Spain US BritainA
s the numberof deaths among people
infected by the new coronavirus
mounts, it is tempting to divide that figure
by the number of reported cases and con-
clude that the result is the fatality rate. Ap-
ply such maths to the world’s total of con-
firmed cases and deaths on March 11th and
you get a fatality rate of 3.6%. But this fig-
ure, which epidemiologists call the “naive”
case fatality rate, may be wrong in two dif-
ferent ways. First, many of the infections
detected at this early stage of the epidemic
are recent, so some will eventually result in
deaths. That will push the fatality rate up.
Second, many infections have not been
spotted because testing for the virus has
been patchy. Lots of mild cases of the dis-
ease have gone unnoticed. If all infections
were actually counted, the result would be
a bigger denominator. That would push the
fatality rate down. As China began to trace
infections more carefully, its fatality rate
fell (see chart 1).
A conclusive measure of the denomina-
tor requires testing for antibodies against
the virus in a large sample of people in a
place which an outbreak has already swept
through. Such studies are under way in
China. In the meantime, researchers have
estimated the fatality rate for covid-19 us-
ing a cohort of people for whom there is a
full count of infections and deaths: passen-
gers on the Diamond Princesscruise ship. A
bungled quarantine on board led to nearly
700 cases of covid-19. Eight people have
died so far. A working paper published on
March 5th by Timothy Russell at the Lon-don School of Hygiene and Tropical Medi-
cine and an international team of research-
ers estimates that the fatality rate among
infected passengers will end up being 1.2%.
The researchers applied the results
from the ship to data on covid-19 cases and
deaths in China. They conclude that the fa-
tality rate for covid-19 in the county’s out-
break was 0.5%. For comparison, that is
five times the fatality rate for the seasonal
flu in America.
The covid-19 fatality rate among those
on the Diamond Princesswas higher partly
because their average age was 58, older
than the general population in any country.
At the same time, they are probably in fairly
good shape. They must be healthy enough
to embark on an extended holiday. People
who go on cruises tend to be richer. So the
fatality rate among these passengers may
be lower than it would be among people of
a similar age in their home countries.
A recent study by researchers at the Uni-
versity of Bern, in Switzerland, sheds more
light. It provides estimates of covid-19 fa-
tality by age group in Hubei, the province
in China with the worst outbreak of the dis-
ease (see chart 2). Fatality is dramatically
higher among people older than 60, rising
to 18% among those in their 80s or older.
But covid-19 may prove no less devastat-
ing for poor countries, which tend to have
younger populations. The disease is more
severe in people whose immune systems
are weakened by chronic diseases, so those
who are malnourished or have hiv/aids
will probably be hit hard.
The fatality rate in any country will de-
pend primarily on the quality of care it can
provide—and how many people have ac-
cess to it. About 5% of people diagnosed
with covid-19 in China have needed inten-
sive care, which is in short supply or non-
existent in most hospitals in developing
countries. A surge in cases even in rich
countries can soon overwhelm hospitals
and result in higher fatality rates. 7Fatality rates for the new coronavirus
could vary enormously by countryDeaths from covid-19Where will it be
worst?
By the numbers
China,covid-19casefatalityratioSources:WHO;“Adjustedage-specificcasefatalityratioduringthecovid-19
epidemic in Hubei, China, January and February 2020” by J. Riou at al.Byregion,amongconfirmedcases,%^120-910-1920-2930-3940-4950-5960-6970-7980+50 10 15 20By age group, Hubei, Jan-Feb 2020, %
251-10 11-20
Jan Feb21-31 1-10 11-20Wuhan 20
Hubei, outside WuhanChina,overallChina,outsideHubei 151050