COVID-19, as the disease is known, is
more lethal than the average seasonal flu, but
less so than previous epidemics stemming
from coronaviruses. We do not yet know its
precise mortality rate.
World Health Organisation data released
Saturday (February 22) identified 2,348
deaths from 76,392 confirmed cases in Chi-
na, for a rough rate of 3.07 percent.
The Chinese Center for Disease Control
and Prevention (China CDC) published this
week a study of 72,314 confirmed, clinically
diagnosed or suspected cases as of February
According to the most extensive study
done so far, the novel coronavirus was be-
nign in 80.9 percent of the cases, “serious” in
13.8 percent and “critical” in 4.7 percent.
The remaining 0.6 percent was not speci-
According to the China CDC study, the
mortality rate increased substantially with
age, and those over 80 were most at risk with
a rate of 14.8 percent.
Patients who already suffered from cardi-
ovascular diseases were also particularly at
risk, ahead of diabetics and those who suf-
fered from chronic respiratory diseases or
Global estimates of the mortality rate are
risky however because we do not know how
many people have actually been infected.
Other strains of coronavirus, such as SARS
and Mers, have established mortality rates of
9.5 percent and 34.5 percent, respectively.
How infectious is it?
Specialists generally agree that each per-
son who falls ill with coronavirus will infect
between two and three others on average.
That is a higher rate than a typical winter
flu (1.3), lower than an infectious disease
such as measles (more than 12), and com-
parable to Severe Acute Respiratory Syn-
drome or SARS (3) — the last major virus
that broke out in China, in 2002-03.
Some experts warn however that we
might be seriously underestimating the
number of cases.
A study published Friday by the Impe-
rial College Centre for Global Infectious
Disease Analysis said: “We estimated
that about two-thirds of COVID-19
cases exported from mainland China
have remained undetected worldwide,
potentially resulting in multiple chains
of as yet undetected human-to-human
transmission outside mainland China.”
WHO chief Tedros Adhanom Ghe-
breyesus voiced concern on Friday
about “the number of cases with no
clear epidemiological link, such as travel
history to China or contact with a con-
Asymptomatic cases, where people
show no symptoms, are another cause
The incubation period is estimated to
be two to 10 days and has led to experts
to decide on an observation period of 14
days for suspected cases or for people
who have been repatriated from areas
such as China’s Hubei province, the epi-
centre of the outbreak.
How is it transmitted?
The virus is mainly transmitted by res-
piratory means and physical contact.
Drops of saliva expelled when an infected
person coughs is a common example, and
researchers believe that generally occurs
over a distance of around one metre
(yard) at most.
Health advisories emphasise meas-
ures such as washing your hands often,
coughing or sneezing into the crook of
your elbow or a paper handkerchief, and
wearing a mask if you know you have
A secondary means of transmission
might be diarrhoea.
What are the symptoms and
WHO says: “Signs and symptoms in-
clude respiratory symptoms and include
fever, cough and shortness of breath. In
more severe cases, infection can cause
pneumonia, severe acute respiratory
syndrome and sometimes death.”
There are no vaccines or medications
at present to fight COVID-19 so health
officials can only treat the symptoms.
Some patients are given anti-viral
medications, but their effectiveness has
not been established so far.
Where did it come from?
The novel coronavirus is believed to
have come from bats, but researchers
think it might have spread to humans
via another mammal species.
Chinese researchers suspect that might
be the pangolin, a widely trafficked and
The global scientific community deems
that hypothesis plausible, but still awaits