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Coronavirus: Things we know and things we don’t know

The researchers want to know everything about the latest coronavirus, from its mortality rate to its origin, incubation period and much more, and they still have gaps to fill.

– Mortality rate? –

COVID-19, as the disease is called, is more lethal than the average seasonal flu, but less lethal than previous epidemics caused by corona viruses. The exact mortality rate is not yet known.

World Health Organization data released on Saturday identified 2,348 deaths from 76,392 confirmed cases in China, an approximate rate of 3.07 percent.

The China Center for Disease Control and Prevention (China CDC) this week published a study with 72,314 confirmed, clinically diagnosed or suspected cases by February 11.

According to the most comprehensive study to date, the novel coronavirus was benign in 80.9 percent of cases, “severe” in 13.8 percent and “critical” in 4.7 percent.

The remaining 0.6 percent were not specified.

According to the China CDC study, the mortality rate increased significantly with age, and the over-80s were the most at risk with a rate of 14.8 percent.

Patients who already suffered from cardiovascular disease were also particularly at risk, ahead of diabetics and patients suffering from chronic respiratory diseases or high blood pressure.

However, global estimates of mortality rates are risky because we do not know how many people are actually infected.

Other strains of coronavirus, such as SARS and Mers, have reported mortality rates of 9.5 percent and 34.5 percent respectively.

– How infectious is it?

Experts generally agree that every person who falls ill with a coronavirus infects on average two to three other people.

This is a higher rate than for a typical winter flu (1.3), lower than for an infectious disease such as measles (more than 12), and comparable to severe acute respiratory syndrome or SARS (3) – the last major virus that broke out in China in 2002-03.

However, some experts warn that we could seriously underestimate the number of cases.

A study published on Friday by the Imperial College Centre for Global Infectious Disease Analysis states that the number of cases could be seriously underestimated: “We estimated that about two-thirds of COVID-19 cases exported from mainland China have gone undetected worldwide, possibly leading to multiple undetected human-to-human transmission chains outside mainland China.

WHO Chief Tedros Adhanom Ghebreyesus expressed concern on Friday about “the number of cases without a clear epidemiological link, such as travel history to China or contact with a confirmed case”.

Asymptomatic cases, where people show no symptoms, are another cause for concern.

The incubation period is estimated to be between two and ten days and has led experts to set a 14-day observation period for suspect cases or for people repatriated from areas such as Hubei Province in China, the epicentre of the outbreak.

– How is it transmitted?

The virus is mainly transmitted via the respiratory tract and through physical contact. A common example is saliva droplets that are emitted when an infected person coughs, and researchers believe that this generally occurs over a distance of no more than about one meter (yard).

Health advice emphasises measures such as frequent hand washing, coughing or sneezing into the crook of the elbow or a paper handkerchief, and wearing a mask if you know you are infected.

A secondary transmission route could be diarrhoea.

– What are the symptoms and treatments?

The WHO says: “The signs and symptoms include respiratory symptoms, including fever, cough and shortness of breath. In more severe cases, the infection can cause pneumonia, severe acute respiratory syndrome and sometimes death”.

There are currently no vaccines or drugs to fight COVID-19, so health authorities can only treat the symptoms.

Some patients receive antiviral drugs, but their efficacy has not yet been proven.

– Where does it come from?

The novel coronavirus is thought to have originated in bats, but researchers believe it may have spread to humans via another mammalian species.

Chinese researchers suspect that this might be the pangolin, a widespread and endangered mammal.

The global scientific community considers this hypothesis plausible, but is still waiting for confirmation.

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