Coronavirus: doctors' answers to your questions

Text by: Caroline Paré Follow | Ophélie Lahccen

Symptoms, contamination, people at risk, transmission ... Here are the questions that the RFI listeners addressed to the doctors and guest professors of the Priority Health program about the Covid-19 epidemic.

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Is a newly infected person who is not yet showing symptoms contagious?

"It can be contagious. We do not yet know everything about this virus. It is probably transmissible a few days before the onset of symptoms. How many days ? Some recent work suggests that it could be just under 24 hours. This transmission before the onset of symptoms, in subjects who have just been infected, explains why there are many people who are carriers of the virus. This aggravates the epidemic phenomenon and the importance of the number of subjects concerned. »- Pr François Bricaire , March 17 on RFI. He is a former head of the infectious and tropical diseases department at the Pitié-Salpêtrière Hospital in Paris.

Is contamination only done during the incubation period?

“No, contamination occurs more at the end of the incubation period. Then the symptoms appear and it is at this point that the contagiousness is strongest, at the beginning of the period when the symptoms appear. The contagion period is said to last around 7-10 days. This is variable in terms of duration, since some incubation periods last 5 days while others, very rare, can last 15 days. »- Professor Pierre-Marie Girard , March 20 on RFI. He is director of the Pasteur institutes network, former head of the infectious diseases and tropical medicine department at Hôpital Saint-Antoine, in Paris.

How to tell the difference between the flu and the Covid-19?

"It's very difficult because the symptoms are similar. Given the current epidemic context, in the event of influenza-like illness, one must have the reflex to suspect the coronavirus. Make a test if possible and especially isolate the patient, who must put on a mask, if he has one (which is often difficult at present). The suspect case must protect others, keeping its distance in everyday life. »- Professor Pierre-Marie Girard , March 20 on RFI. He is director of the Pasteur institutes network, former head of the infectious diseases and tropical medicine department at Hôpital Saint-Antoine, in Paris.

Which age group is most exposed to coronavirus and its complications?

“What we have known from the start is that the elderly were indeed the most vulnerable at the start of the epidemic. Obviously, the age group is advancing a little and it is said today that people between 30, 40 and 50 years can also be infected. "- Dr. Frédéric Béhar , March 17 on RFI. He is a geriatrician and nutritionist, head of service at the Joffre-Dupuytren Hospital in the Paris region.

Why are older adults more vulnerable to Covid-19 than children?

“The elderly are more vulnerable because their bodies have less capacity to resist infections and diseases in general. For children, this is still a bit mysterious. Why do children, especially those under 18, do very little clinical illness? There are only assumptions; we have no evidence at this time. One of the hypotheses would be that children, especially in their young age, had many nasal infections, with other common coronaviruses. It might give them some immunity. In toddlers, their lungs may be immature enough that the virus cannot damage it aggressively. For the moment, these are tracks, we do not know exactly. »- Pr Olivier Bouchaud , March 25 on RFI. He is responsible for the infectious and tropical diseases department at the Avicenne University Hospital, in Bobigny, in the Paris region.

Is black man more resistant to coronavirus than white man?

" NO ! It is a zany idea which consists in saying that the black man, having a little more melanin in his cutaneous layer, resists better than the white man… It is a false idea! »- Pr Jean-Marie Kayembe , March 24 on RFI. He is head of the pulmonology department at university clinics in Kinshasa, in the DRC, dean of the Faculty of Medicine in Kinshasa.

Is there a link between Ebola and Covid-19, especially in terms of prevention?

" Not at all. Things have to be very clear. The coronavirus is spread like the flu, through the droplets of saliva. The only small point in common is that these droplets of saliva can be deposited on surfaces and that by contact, you can infect your hand and then bringing your hand to your face, you can be infected, through this. Apart from that, the contamination is not the same. »- Pr Olivier Bouchaud , March 25 on RFI. He is responsible for the infectious and tropical diseases department at the Avicenne University Hospital, in Bobigny, in the Paris region.

Why do we limit the duration of isolation to 14 days and not beyond?

“Over 99% of contaminations are made during this 15-day period, after the onset of symptoms. We must not go to extremes. We must be reasonable in the recommendations. »- Professor Pierre-Marie Girard , March 20 on RFI. He is director of the Pasteur institutes network, former head of the infectious diseases and tropical medicine department at Hôpital Saint-Antoine, in Paris.

Can a person with Covid-19 be cured without the intervention of a doctor?

“Yes, 80% of those affected can recover from Covid-19 without medical intervention. Paracetamol is the only thing to take to treat fever. - Dr Massamba Sassoun Diop , March 19 on RFI. He is an emergency doctor and president of SOS-Médecins in Dakar, Senegal, and since December 2019, president of the Senegalese Society of Anesthesia, Resuscitation and Emergency Medicine.

Can a person cured of coronavirus be reinfected?

"Overall, we think not. There is a form of protection that is created, from having already developed the infection, but it is not known, at this time, if it is perfect. »- Professor Pierre-Marie Girard , March 20 on RFI. He is director of the Pasteur institutes network, former head of the infectious diseases and tropical medicine department at Hôpital Saint-Antoine, in Paris.

Does the virus stay on food? For example, when people touch fruits and vegetables in supermarkets, can it contaminate them?

“On plastic surfaces (eg computer, doorknob), we know that the virus can stay up to 48 hours. On leather, we think it would only remain 3 hours, while on cardboard, we think rather of 24 hours. We are not sure of anything about fruits and vegetables, so they should be washed well before cooking. - Dr Massamba Sassoun Diop , March 19 on RFI. He is an emergency doctor and president of SOS-Médecins in Dakar, Senegal, and since December 2019, president of the Senegalese Society of Anesthesia, Resuscitation and Emergency Medicine.

Can the virus be transmitted through contact with perspiration, for example when you are crowded with other people in transport?

“For the moment, the virus is not considered to be excreted by sweat. But you have to stay humble ... Since it is recommended to stay 1 meter away, there should not be this problem. Above all, wash your hands frequently. We touch several hundred times (we sometimes say 3,000 times), the face in the space of 24 hours. Do not touch the mucous membranes of the face: mouth, nose, eyes. When you are at home and have washed your hands, there is no problem, but when you are outside, this is really what you should avoid doing. When you are crowded in public transport, it's complicated, but you have to try to manage not to find yourself facing the postilions of the neighbor. - Dr Massamba Sassoun Diop, March 19 on RFI. He is an emergency doctor and president of SOS-Médecins in Dakar, Senegal, and since December 2019, president of the Senegalese Society of Anesthesia, Resuscitation and Emergency Medicine.

Are smokers more vulnerable to coronavirus?

" Yes. When you are a smoker, the lining of the bronchi (the surface of the bronchi) and overall of the lung is permanently inflammatory. This inflammation weakens the natural response to fight the arrival of a microbe. A smoker is more likely to be infected and to become more prominent or even more serious. »- Pr Olivier Bouchaud , March 25 on RFI. He is responsible for the infectious and tropical diseases department at the Avicenne University Hospital, in Bobigny, in the Paris region.

Are asthmatics more vulnerable?

“It is difficult to answer with certainty. Common sense dictates that an asthmatic person, who would trigger an asthma attack when they have a lung or bronchial infection with the coronavirus, will necessarily experience an increased risk. However, we have no reason to believe that being asthmatic makes you more susceptible to infection. »- Pr Olivier Bouchaud , March 25 on RFI. He is responsible for the infectious and tropical diseases department at the Avicenne University Hospital, in Bobigny, in the Paris region.

Does the Covid-19 survive outside temperatures above 20 ° C?

“Covid-19 delights in the human body, whose temperature is usually around 37 ° C. Obviously, temperatures above 20 ° C suit him perfectly. And even when the body rises to 39-40 ° C, it does not seem to weaken it. »- Pr Olivier Bouchaud , March 25 on RFI. He is responsible for the infectious and tropical diseases department at the Avicenne University Hospital, in Bobigny, in the Paris region.

We hear that you have to drink hot drinks to fight coronavirus. Is it true ?

“It doesn't make sense from a virological point of view. Drinking regularly is very good. Some people should not think that you should drink hot drinks while thinking of disinfecting and getting rid of the coronavirus. This may cause burns in the throat, which would weaken the mucous membranes and natural defenses. They would then be more likely to get an infection. »- Pr Olivier Bouchaud , March 25 on RFI. He is responsible for the infectious and tropical diseases department at the Avicenne University Hospital, in Bobigny, in the Paris region.

Can we envisage a systematic screening of Covid-19, for the whole population?

“If we had rapid diagnostic tests, we could consider expanding screenings. However, current capabilities do not allow this. Even developed countries do not necessarily currently have these capacities. In China, in Hubei province, where Wuhan, the first focus of the epidemic, is located, this is what they had tried to do. Systematic screening is what we should aim for, who to isolate, etc. - Dr Massamba Sassoun Diop , March 19 on RFI. He is an emergency doctor and president of SOS-Médecins in Dakar, Senegal, and since December 2019, president of the Senegalese Society of Anesthesia, Resuscitation and Emergency Medicine.

Every day, ask your questions by email at priorite.sante@rfi.fr or by phone at +33 1 84 22 75 75 .

Our selection on SARS-CoV-2 coronavirus

• Listen to Infos coronavirus , our daily column on the Covid-19

• Practical questions:
→ What is the lifespan of the virus?
→ Who are the vulnerable people ?
→ What should you do when you think you are contaminated ?
→ Quarantine, what are we talking about ?
→ What treatments ? The effectiveness of an antimalarial drug in question
→ The advice of a psychiatrist to live well the confinement

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See also our contents on containment .

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