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Covid-19 in France: What we know (and do not) so far

Clinical trials and scientific studies on the origin, spread and nature of Covid-19 are continuing, as the global Discovery project continues from Lyon (‎Auvergne-Rhône-Alpes). We summarise what we know so far.

The Discovery project is a vast clinical trial spearheaded by national medical research unit l'Institut National de la Santé et de la Recherche Médicale (Inserm). It is analysing the safety and efficacy of four investigational therapies - including the controversial drug, hydroxychloroquine - in a minimum of 800 severe Covid-19 patients in France.

In total, it is expected to study 3,200 participants across France, Belgium, Germany, Luxembourg, the Netherlands, Spain, Sweden and the UK.

Speaking to news service FranceInfo, lead researcher Professor Florence Ader, based in Lyon, said: “We are progressing at lightning speed, and moving very quickly into the research.”

Beyond Discovery, FranceInfo has rounded up the current, main scientific knowledge about SARS-CoV-2 - the virus that causes Covid-19 - and Covid-19 itself, so far. We summarise and translate the main findings.

What we know so far

The family the virus belongs to

SARS-CoV-2, the virus that causes Covid-19, is a coronavirus. These viruses are well-known, and are called “corona” due to proteins that appear “crown-like” under a microscope. “Corona” means “crown” in Latin.

These viruses cause respiratory problems, and are very common in animals, especially bats and camels.

We already know that SARS-CoV-2 is part of the same group as the Severe Acute Respiratory Syndrome SARS, which killed around 800 people in 2003; and Middle East Respiratory Syndrome (MERS), which killed 500 people in 2012.

The virus genome

The genome is the virus’ “identity card”, says Professor Ader. It holds its genetic material. SARS-CoV-2 (initially named 2019-nCoV), was officially discovered by Chinese authorities and the World Health Organization (WHO) on January 9, 2020.

Three days later, Chinese scientists sequenced the genome - meaning they identified its genes. Based on this, scientists are now able to understand more on the virus’ characteristics and how it works.

Sylvie van der Werf, head of national respiratory virus centre le Centre National de Référence des Virus Respiratoires at Paris research site the Institut Pasteur, said: “Sequencing the genome of pathogens is crucial for specific diagnostic tests and identifying potential intervention options.”

Sequencing the genome is seen as one of the first steps on the path towards producing a vaccine. The Institut Pasteur itself sequenced the entire genome on January 29, by analysing French samples, and comparing them to other sequences from around the world.

The main ways the virus spreads

Human-to-human spread mainly happens via the respiratory tract.

The virus is spread through saliva drops and invisible secretions, which are spread when someone coughs or sneezes.

This mainly happens through close contact, which is why the recommendations say that people should keep at least 1-2 metres away from others.

The virus can also be spread by physical touch, if someone touches an infected surface and then touches their face (such as their eyes, nose or mouth).

One US study, published in the New England Journal of Medicine, showed that the virus can theoretically stay alive for several hours, if not days, on surfaces such as plastic, stainless steel, and cardboard.

The illness symptoms

We know that Covid-19 symptoms include headaches, muscle pain, and fatigue, followed by a high fever of more than 38°C, and a dry cough.

Some patients also present with nasal congestion or a runny nose, as well as a sore throat or diarrhea, according to the WHO. The virus can also cause people to suffer a loss of smell or taste.

Some patients have also reported skin issues, such as frostbite-like symptoms, or a persistent rash.

Increased knowledge on reported symptoms may allow doctors to “shorten the diagnosis time”, said Professor Ader, leading to quicker diagnosis and treatment.

Scientists also know that some patients may have the virus but not show any symptoms, leading them to be “asymptomatic carriers” - people who can spread the illness, but do not have any clinical signs of it themselves.

The illness timeline

This is “pretty well known”, said Professor Ader. The incubation period - the time between infection and the first symptoms beginning to appear - is estimated to be around five days, but in some extreme cases it can last as long as two weeks, the WHO said.

A study on 181 Chinese Covid-19 patients found that 97.5% of those who developed symptoms did so within 11.5 days of contamination.

A study in medical journal The Lancet, on the first five confirmed cases in France, suggests that the virus tends to develop in one of three key ways.

Firstly, some patients show few symptoms and rapidly improve, according to Inserm. Secondly, others show relatively mild symptoms in the first 10 days, with a sudden spike in the severity of the illness around the 10th day, despite their viral load having dropped.

Thirdly, some patients quickly develop a severe form of the illness and present with a very high viral load in their respiratory system.

People who may be at risk

Some people are at greater risk of developing a severe form of the virus, said national health council le Haut Conseil de Santé Publique (HCSP).

This includes people aged 65 and over, who accounted for 92% of deaths and 50% of intensive care admissions in France between March 1 and April 14, said health authority Santé Publique France, in an update published on April 16.

Some existing conditions also appear to increase the risk of developing a severe form of the illness - including diabetes, chronic respiratory issues, chronic kidney damage, cirrhosis of the liver, morbid obesity, cardiovascular conditions; and people currently being treated for cancer, or who are immuno-compromised.


What we do not yet know

Where the virus came from

Scientists have said that the virus is likely to have come from an animal, but this link has not yet been clearly established.

Chinese researchers have said the source may be the pangolin, a small endangered mammal. The global scientific community has judged this to be a plausible hypothesis, but no study has confirmed it.

It is still unclear exactly how viruses jump between animals to humans, but on Tuesday (April 21), a spokesperson from the WHO confirmed during a press conference that there would “certainly” have been an “intermediate animal host”.

The WHO has denied any suggestions that the virus was “made in a laboratory”.

The exact treatment

There is still not a single, recognised treatment plan against Covid-19.

Several antiviral medications are undergoing tests, including as part of the Discovery project.

Alongside this, more than 150 studies worldwide are currently working to find a vaccine.

In France, the Institut Pasteur is planning to start its own vaccine research on humans by the summer, said Professor Ader.

William Dab, epidemiologist and former French director general of health, added: “No-one believes that we will have a vaccine before [at least] 12-18 months.”

The reason some suffer worse than others

Professor Ader said: “It is still very difficult to predict which patients will develop severe forms of the illness and which will develop less severe forms.”

Some risk factors have been identified (see above), but it is not yet clear exactly which patients might suddenly see a decline in their condition around the 10th day of experiencing symptoms.

A hyperinflammation condition known as a “cytokine storm” - an overreaction of the body’s immune system when faced with a threat - can lead to Covid-19 becoming fatal in some patients.

Cytokines are proteins that help the body to beat infection; but in some people, excessive levels are released (especially when the virus enters the lungs), causing an often-fatal level of inflammation.

The difference between men and women

Men appear to be more likely to become ill than women. In France, figures from Santé Publique France (published April 20) show that 53.3% of currently hospitalised patients are men (16,068 people) versus 46.7% women (14,095 people).

Men have accounted for 59.7% of hospital deaths (7,407) compared to 40.3% women (4,998).

There is currently no consensus on why this is the case. Some theories have been suggested, including the fact that men often suffer from more severe pre-existing conditions, such as hypertension, diabetes or cardiovascular problems.

Others have said the difference may be genetic, while one report in the newspaper the HuffPost suggested that the hormone oestrogen - of which women have much more than men - could help to stimulate a better immune response against the virus.

How the virus behaves in children

Children appear to be less susceptible to the virus than adults.
Robert Cohen, paediatrician at the Créteil hospital in ‎Île-de-France, told FranceInfo that Covid-19 tests on children come out positive “three to fives times’ less” than the equivalent number on adults.

However, this does not mean that they do not contract the virus. It could be that they are more likely to be asymptomatic carriers.

It is also not known how contagious children are. Originally, it was thought that children could be very contagious, as is the case with ‘flu.

Yet, a study of one of the earliest “clusters” of the illness in France - in the commune of Contamines-Montjoie (Haute-Savoie, Auvergne-Rhône-Alpes) - found that one infected child had not spread the illness to anyone, despite having been in contact with 172 people in the early stages of the infection.

Kostas Danis, epidemiologist and lead researcher of the study, said: “It is possible that children - because they do not present many symptoms and have a low viral load - barely spread this new coronavirus.”

How long people remain contagious

It is still not clear exactly how contagious patients are, or when, once they have the virus.

One study of 94 Chinese patients, published in the journal Nature Medicine, said that infected people are likely contagious two to three days before the first symptoms appear.

Another study, published in The Lancet, showed that the virus was still detectable in patients (who had had a severe form of the illness) up to 24 days later.

Immunity against the virus

It is not clear if people can be contaminated twice, or if people become immune to the virus once they have had it; nor if so, how long this immunity might last.

Professor Jean-François Delfraissy, president of the Covid-19 government advisory council le Conseil Scientifique, told the French Senate on April 15: “We do not know if having antibodies constitutes absolute protection. And we are not going to be able to find this out quickly.”

One as-yet unverified Chinese study, published on the “preprint” medical platform MedRxiv, said that some patients who have had the virus do not even produce antibodies against the illness. That study was conducted on patients from China and South Korea, who had already had the virus and been cured, but had contracted it for a second time.

It is currently not clear whether these “second infection” patients had actually been tested incorrectly the first time, whether they had genuinely been infected for a second time, or whether their “second positive test” was actually showing that they had not quite been cured of their first illness.

The consequences for the heart and brain

The virus is known to affect the heart and brain as well as the lungs, according to initial studies.

Some patients have presented with neurological problems, such as dizziness or fainting; while others have shown heart difficulties.

Currently, the extent of these issues is not well-known.

The geographical variation in symptoms

It is also not clear why some symptoms appear more common in some areas of the world than others.

For example, some European patients have reported a severe loss of taste and smell, but this symptom was barely reported in China.

Professor Anne-Claude Crémieux, infectious diseases specialist, told newspaper Le Parisien: “Apparently, the virus appears differently among different populations.”

However, the reason for this is still not known.

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