A brand-new coronavirus is causing an epidemic in China and is beginning to spread to other countries. The health situation is widely commented on in the media, but should we really be worried? A specialist in virology answers us.
It all started about ten days ago, in early January 2020: a World Health Organization communiqué reported the emergence of a small epidemic in China. It’s rooted in the center of the country, in Wuhan. The cause is a “new” virus, never identified before. Since that first announcement, the situation has grown. The dangerousness of the epidemic seems more serious than expected. In this context, the multiplication of alarmist information can be worrying, especially since news on this subject is systematically found in one of your favourite aggregators. But how justified is that? What do we really know about this virus and its severity? We take stock of the situation with the help of Tania Louis, a doctor of biology and virologist, in order to understand the situation.
Even though the virus is new, the symptoms are well identified: more precisely, it is an epidemic of pneumonia expressed by breathing difficulties, cough and fever. This Wednesday, January 22, 2020, nearly 300 cases of infections have been recorded, in varying states, sometimes serious. Nine patients died. The epidemic is spreading to several cities in China and has spread beyond the country’s borders, with cases recently diagnosed in Thailand, Japan, Australia and a case recently reported in the United States.
Shanghai is also affected by the new coronavirus // Source: Pixabay
The virus, named 2019-nCov, is more specifically a coronavirus. Within this family, we can find simple colds as well as severe acute respiratory syndrome (SARS). It is the shadow of the latter that worries, as there are many similarities between the mysterious Chinese virus and SARS. However, this syndrome had triggered a deadly epidemic in 2002 / 2003: 8,000 cases of infection including 700 deaths.
However, the proximity between the two viruses does not mean that they have the same level of severity. “Viruses are not categorized according to their impact on the organism they infect, but according to their structural, genetic proximity… that’s why, in the same family, there will be viruses with very different consequences,” Tania Louis told Numerama. She cites the example of the flu: Spanish flu was a severe global pandemic, where seasonal flu causes few deaths. Yet, “their strains are closer together than nCov and SARS.
The dangerousness of a virus is measured by the proportion of lethality
In the case of nCov, the virus has already caused nine deaths as of 22 January, but it is crucial to remember that this does not yet give any real indication of how dangerous it is. As virologist Tania Louis tells us, the severity of a virus is measured by the “lethality ratio“, which is the number of deaths relative to the number of infected people (1 death per 1,000 infected would indicate low lethality).
However, the actual number of people infected is not known at this time. This number is constantly increasing (nearly 300 at present) also and above all, as detection is improving. A study released on Friday, January 17 suggests that there may in fact be thousands of people infected. According to this analysis, it is likely that many people were infected without realizing it: “respiratory symptoms, similar to a cold, are not so specific, especially in the middle of winter“.
A virus currently less dangerous than measles
If this estimate of thousands of infected people is confirmed and this figure is put in relation to the number of deaths, the famous lethality ratio is quite low. In fact, the dangerousness of the virus would not be so high. Another factor to be taken into account is the profile of the patients. According to initial information, the deceased were generally quite old. For example, the fourth patient who died was 89 years old and had health problems, including one at the heart: his immune system was weakened. At the same time, many people have been infected with nCov and have come out of it cured. It is even possible, as mentioned earlier, that people may become infected and mistake it for a winter influenza-like condition.
“For the moment, we are on a virus less dangerous than measles,” reassures Tania Louis to Numerama. By way of comparison, in France, influenza killed more than 2,800 people in 2019.
The outbreak started in a market in Wuhan where seafood, chickens, bats and other live wild animals are sold. It seems likely that the original transmission occurred through contact with an infected animal. But on Monday, January 20, a leading Chinese scientist said on television that human-to-human transmission was now “proven”.
No human-to-human transmission has been technically observed in the medical sense, but a key clue supports this thesis: Chinese authorities have announced that fifteen medical personnel in Wuhan were infected. This alone is enough to make it almost certain that the transmission is human-to-human. That is why the risk of a growing epidemic is very present. But, here again, the virologist Tania Louis delays: “there are more or less efficient transmissions“.
The most important risk: mutation
However, one detail darkens the picture: Chinese New Year, a sign of great displacement among the population. People who are not usually in contact are going to be close, to meet each other, to touch each other, before leaving. In the context of an epidemic, the risks are there for such movements to increase the number of infected people. “The more infections there are, the more likely it is that the virus will become virulent,” says Louis. This is where the risk of mutation arises, which would cause the virus to evolve into a more resistant structure than today: “A virus mutates by getting used to its host“. Containing the number of infected people therefore reduces the danger of the virus.
- Read: A new virus triggers an epidemic in China: what do we know about it?
In its very first communiqué, the World Health Organization stated that “China has a strong public health infrastructure and resources to respond to and manage outbreaks of respiratory diseases. “Since the SARS epidemic in 2002 / 2003, regional and global infrastructures are much better prepared for this type of epidemic. Tania Louis added that the SARS epidemic could already be considered to have been properly contained at the time. However, the new virus is far less virulent at the moment. The context is promising.
The precautionary principle has made it possible to take action at a very early stage. The United States has announced enhanced medical screening of all persons arriving from Wuhan at three U.S. airports: San Francisco, New York JFK and Los Angeles. In a press release dated 17 January, France also announced an enhanced security plan. Health Minister Agnès Buzin indicated on January 21 that recommendations were also given to airports.
“There’s nothing to worry about.”
On a purely medical level, too, the situation is well managed. The nCov genomic sequence was identified and then quickly shared free of charge so that all laboratories could work on it. The virologist says the good news is significant: “Now we can study the virus in the lab, start producing diagnostic tests, look for vaccines and treatments. »
For Tania Louis, it is clear that it is still far too early to be truly alarmed by the situation. On the contrary, crisis management is good. “There’s nothing to worry about. If we have information that comes to us, it is precisely because there is a whole surveillance system in place: being vigilant and taking action, that is how we contain an epidemic. »
The World Health Organization has scheduled an emergency meeting for Wednesday, January 22. The Chinese Health Commission should also issue an update on the situation.