Since the first reports of coronavirus were reported on January 5, scientists have multiplied the discoveries on this new virus, but many unknowns still prevent from determining the global impact of the epidemic.
“A mysterious pneumonia”. This was how the 2019-nCov coronavirus was presented when it was first reported by the Chinese authorities, Sunday, January 5. The disease had infected 59 people in Wuhan, leaving no one dead.
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According to a last report provided Monday, February 3, 361 patients died out of 17,200 confirmed cases in China. The first death outside of this country was reported Sunday in the Philippines, a 44-year-old Chinese from Wuhan, on the 150 patients listed in 24 other countries, including France. In a month of epidemic, the scientific community has already amassed a large amount of knowledge on this virus, even if gray areas remain. Mortality rate, symptoms, incubation period … Franceinfo takes stock of what we know and what we do not yet know about the epidemic.
What we know
A virus transmissible between humans. Human-to-human contamination has been proven to date, says the Ministry of Health in his bulletin of January 31. Initially considered to be zero or low, this risk is now established due to the occurrence of pneumonia due to this virus in Chinese caregivers having taken care of the first sick patients, and the spread of the epidemic in China, specifies the Institut Pasteur. The main cases of direct contagion between humans have been observed in China, but others have been reported in Vietnam, Germany, Japan, the United States and France. A liberal Parisian doctor was thus contaminated, Thursday January 30, after having received in consultation a Chinese national reached of the virus.
Symptoms close to those of a moderate flu. “The virus can cause symptoms similar to those of a moderate flu”, explains the Ministry of Health. 2019-nCoV thus causes fever, cough and difficulty breathing. More severe symptoms may be observed in patients with preexisting chronic diseases (hypertension, diabetes or even cardiovascular diseases).
“It is likely that this coronavirus is similar to that of other human coronaviruses, which are generally transmitted through close contact after inhalation of infectious droplets emitted during sneezing or coughing by the patient or after contact with fresh surfaces contaminated with these secretions “, added Public health France.
Find all the information and our health recommendations on: https://t.co/0I8koxOdgq pic.twitter.com/ia3qJPEKw0
– Ministry of Solidarity and Health (@MinSoliSante) January 31, 2020
A level of contagion comparable to Sras. This is one of the important parameters for determining the severity of the epidemic: the level of transmission of the virus. To establish it, we must be able to calculate the number of people infected by a sick person. This is what scientists call the “basic reproduction rate” or R0. Several estimates have been made by different research teams, ranging from 1.4 to 5.5. A study Chinese appeared in the medical journal New England Journal of Medicine thus estimates that each patient infected an average of 2.2 people. It is higher than winter flu (around 1.3), but much lower than measles (more than 12), and comparable to Sras (3), which killed 349 people in 2002-2003 in China and 774 worldwide.
What we don’t know yet
The exact origin of the virus. According to Chinese authorities, the majority of the first sick people went to the Wuhan market (closed since January 1, 2020). Even if 2019-nCoV is very close to a virus detected in a bat, the animal responsible for transmission to humans has not yet been identified with certainty, specifies Institut Pasteur.
The precise duration of incubation. Scientists have established the first estimates of the incubation period of the coronavirus, that is to say the time between infection by the virus and the appearance of the first symptoms. WHO estimates it to last between two and ten days on average. According to the study published in the New England Journal of Medicine, it is around 5.2 days on average and varies greatly depending on the patient. Previous work in the Netherlands has averaged 5.8 days. Finally, for the Institut Pasteur, it seems to be around 7 days but can be up to 14 days.
Death rate. For the moment, it is impossible to know precisely the mortality rate linked to this coronavirus, since it is not known how many people are actually infected. The evoked estimates of the mortality rate vary between 2% and 3%. “Two percent of confirmed cases are dead, which remains high when compared to seasonal flu”, said Wednesday Michael Ryan, director of emergency programs at WHO. This is less than the mortality rate of SARS, which amounted to 9.5%, recalls the organization. But this indicative figure drops every day. And for good reason : the number of new cases is increasing faster than the number of deaths.
The stage of contagion. When does a patient become contagious? This question remains unanswered for the moment. Chinese authorities have argued that contagion is possible before symptoms even appear, which is the case for influenza but not for SARS. This assumption is however not confirmed. If a patient was truly contagious before developing symptoms, this would make it difficult to identify cases and could therefore make the spread of the virus more difficult to contain.
The precise profile of the patients. Thanks to the analysis of the first 99 cases identified in China, published in the medical journal The Lancet, the clinical picture of the disease becomes clearer. The average age of these patients is 55 years, two thirds are men and half suffer from chronic diseases (cardiovascular problems, diabetes…). But many questions remain unanswered. “How to explain that children under 15 are very little affected? We do not know, even if this news is reassuring”, highlighted Professor Yazdan Yazdanpanah, head of the infectious diseases department at Bichat hospital, in Paris, in The cross. “Why do some patients get worse on the seventh day?” He added.
How to prevent and treat the disease. There is still no vaccine or medicine for the coronavirus. Medical management consists of treating the symptoms, including fever. But possible treatments are being studied. Chinese researchers very quickly shared the genetic sequence of 2019-nCoV. This has enabled several countries, including France, to develop their own diagnostic tests.
Labs around the world are working on a vaccine. In France, the Institut Pasteur welcomed on Friday having cultivated strains of the coronavirus, important step towards a vaccine and treatment.
While the complete sequencing of the viral genome of #coronavirus has just been completed, the isolation of strains of the 2019-nCoV coronavirus detected in France has just been successfully completed at@Pastor Institute in a very short time. https://t.co/t2933EMd35
– Institut Pasteur (@institutpasteur) January 31, 2020
On the same day, the European Commission announced a € 10 million grant to support research on the virus. On the corporate side, pledges have multiplied. The co-founder of the Chinese company Alibaba, Jack Ma, decided to donate 100 million yuan (13 million euro) looking. Apple CEO Tim Cook has pledged “a donation to groups on the ground who help all those affected”, without however specifying the amount.
As people in China and around the world celebrate the Lunar New Year, we send our love and support to the many impacted by the Coronavirus. Apple will be donating to groups on the ground helping support all of those affected.
– Tim Cook (@tim_cook) January 25, 2020
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