Covid-19 disease continues to make new patients around the world. A recent study shows that the Sars CoV-2 virus has mutated into a more contagious form. Symptoms, incubation period… Latest COVID-19 World Live Update.
COVID-19 World Live Update
On 9 January, the virus responsible is identified, it is a new coronavirus called Sars-CoV-2. In July, this highly contagious virus spread to the five continents of the Earth and contaminated more than 11 million people in more than 188 countries, out of 198 in total, causing more than 544,000 deaths, according to John Hopkins University.
According to the World Health Organization, Covid-19 would be 10 times more deadly than H1N1, the virus responsible for the flu pandemic in 2009. Symptoms, incubation period, contagion, mutation, people at risk… An update on current knowledge.
After having been named nCoV-2019 in the first instance, this new coronavirus has been called SARS-CoV-2 (SARS for “Severe Acute Respiratory Syndrome” and CoV for “COronaVirus”). Its disease was named Covid-19 on February 11, 2020 by the WHO to mean :
- “Co” means “corona”,
- “vi” for “virus” and
- “D” for “disease.”
The number 19 indicates the year of onset: 2019. “We had to find a name that did not refer to a geographical location, an animal, an individual or a group of people,” said WHO Director-General Dr Tedros Adhanom Ghebreyesus, to avoid stigmatizing the disease.
CoV-2-SARS belongs to the family of coronaviruses (with a large number of viruses) that can cause mild illnesses in humans such as colds and more serious conditions such as Sras.
Since the beginning of the epidemic, the most plausible lead according to scientists has been animal contamination. The epidemic started in a local market in Wuhan, China, where wild animals were sold.
At present, we still do not know for certain which animal is responsible. It could be the bat where a virus very close to Sars CoV-2 has been detected.
On 7 February 2020, scientists from the South China Agricultural University identified pangolin as a “possible intermediate host” suspected of having transmitted the coronavirus to humans.
This small mammal consumed in southern China could be involved as an intermediate host between bats and humans. The pangolin is an endangered scaly mammal whose delicate flesh is highly prized in Chinese and Vietnamese gastronomy.
In a press release, scientists explain that an animal can carry a virus without being sick and transmit it to other species such as humans.
After analyzing 1,000 samples, the scientists were able to show that the genomes of virus sequences taken from pangolins were 99% identical to viruses found in people with nCoV, New China said. During the 2002-2003 Sras outbreak, the intermediate host of the virus was the civet, a small, gray-coated animal whose meat is consumed in China.
The bat was also responsible for the transmission of viruses to humans, including Sras, MERS in Saudi Arabia and Ebola. However, on April 17, Professor Luc Montagnier, Nobel Prize for Medicine in 2008, asked why Doctor refutes this hypothesis of contamination.
According to him, the new coronavirus was manufactured in laboratories in Wuhan: “The laboratory in the city of Wuhan has specialized in coronaviruses for a very long time (…) they have expertise in this field” he recalls.
Professor Montagnier looked at the description of the genome of the coronavirus: “The complete genome of this new coronavirus had sequences of another virus which is HIV, the AIDS virus. This was published by Indian researchers who were forced to retract it.
There’s enormous pressure to get the truth out.” To insert an HIV sequence into the genome you have to have molecular tools, it can’t be related to a natural mutation, the scientist explains. “The hypothesis is that this virus is coming out of Wuhan’s laboratory, (…) the story of the fish market is a beautiful legend,” he says.
The United States claimed on May 5 that it had “evidence” that it came from a Wuhan laboratory, and President Donald Trump threatened Beijing with “punitive customs duties”.
But the WHO remains cautious: “We have not received any specific data or evidence from the US government regarding the presumed origin of the virus, so for us it remains speculative,” said Michael Ryan, WHO director of emergency programmes, at a virtual press conference.
On 1 May, the WHO had assured that the new coronavirus was “of natural origin”, according to many scientists, and not man-made. An opinion shared by Dr Olivier Schwartz of the Pasteur Institute: “In the laboratory, one can manipulate certain viruses to modify some of their components, but one cannot create a new virus by mixing two viruses of different species. You can’t create a coronavirus by taking one element of HIV and another virus” .
What are the risk factors?
→ Age appears to be a risk factor for severe forms of COVID-19 with case-fatality rates for clinical forms of the infection close to 15% in people over 80 years old while it is estimated to be 3/1000 (0.3%) in people under 60 years old, indicates the Scientific Council Covid-19 in an Opinion of June 2nd. In France, among hospitalized patients, the risk of severe forms (admission to intensive care and/or death) was 3 times higher in people over 65 years old (unpublished data from Cohorte FrenchCOVID).
→ Gender: Men are more at risk of severe forms .
→ The presence of comorbidities is another risk factor for severe forms. The main comorbidities are high blood pressure, diabetes, coronary heart disease, and overweight.
→ Precariousness is another risk factor documented more recently by a British study. In Ile-de-France, the observed excess mortality rate was highest in Seine-Saint-Denis, a department where the indicators show the highest rates of precariousness. This point would need to be clarified by ad hoc epidemiological studies as it is still underestimated at the level of public decisions.
Who are the people at risk of serious forms of the disease?
Populations at risk of severe forms or death are better known: age and certain co-morbidities appear to be risk factors for severe forms of COVID-19 with high case-fatality rates. Precariousness is another risk factor documented more recently in several countries and found in Ile de France.
The list of persons at risk of severe forms of Covid-19 was defined in the notice of 31 March 2020 and updated in the notice of 20 April.
people aged 65 and over (although people aged between 50 and 65 should be monitored more closely) : People aged 65 and over account for 58% of inpatient intensive care patients and over 76% of deaths.
ndividuals with a history (CDTA) of cardiovascular disease: complicated hypertension (with cardiac, renal and vascular complications), CDTA from stroke or coronary artery disease, heart surgery, NYHA stage III or IV heart failure* ;
“A new version of the virus began to circulate through Europe, followed by North America and Oceania, then Asia.”
insulin-dependent diabetics or diabetics with complications secondary to their condition. Among diabetics, the Société francophone du diabète explains that the symptoms of Covid-19 are not different: cough, fever, aches, fatigue but also sometimes digestive signs.
On the other hand, the infection will tend to unbalance the diabetes (just like the flu). In the presence of a cough and fever in a person with diabetes, the absence of a significant imbalance of diabetes is a reassuring element that goes against Covid-19 – but in an epidemic situation, it’s important to stay at home.
If there is a diabetes imbalance, there is a significant risk of ketotic decompensation; people with a chronic respiratory pathology likely to decompensate during a viral infection (obstructive bronchopneumopathy, severe asthma, pulmonary fibrosis, sleep apnea syndrome, cystic fibrosis in particular);
- patients with chronic renal failure on dialysis;
- patients with active cancer under treatment (excluding hormone therapy);
- people with obesity (body mass index (BMI) > 30 kgm-2);
- people with congenital or acquired immunosuppression (drugs: cancer chemotherapy, immunosuppressive therapy,
- biotherapy and/or corticosteroid therapy at immunosuppressive doses; uncontrolled HIV infection or infection with CD4 < 200/mm3 ;
- following solid organ or haematopoietic stem cell transplant;
- related to haematopoietic malignancy during treatment);
- Patients with cirrhosis at least at stage B of the Child Pugh score;
- people with major sickle cell disease or with a history of splenectomy;
- pregnant women, in the third trimester of pregnancy, taking into account the available data and considering them to be very limited.
The virus was mutated?
According to an American study published in the journal Cell on 26 June 2020, a variant of the virus as it appeared in China in December 2019 would have “become the dominant form worldwide of SARS-CoV-2”.
“The transition from D614 (original version) to G614 (now circulating virus) occurred asynchronously in different regions of the world, starting with Europe, followed by North America and Oceania, and then Asia,” the researchers explained.
This new “version” of the coronavirus is thought to be more contagious than the original. “G614 is associated with potentially higher viral loads in COVID-19 patients but not with more severe disease,” they continue after analysing data from 999 Covid-19 patients.
Namely: While the mutation of the virus is cause for concern, Dr Gerard Kierzek reminds us that it is not necessarily more dangerous for humans: “The mutation can go either way, towards more virulence or less virulence, more contagiousness, less contagiousness.”
What are the symptoms of a Covid-19 infection?
Unlike the flu which sets in suddenly, a coronavirus infection “occurs gradually over several days” says the Pasteur Institute. Sick people report symptoms that appear over a week and a fairly long recovery time.
“In more than 80% of cases, the signs are quite minor. They are angina or rhinopharyngitis,” said Professor Karine Lacombe, head of the infectious diseases department at the Saint-Antoine Hospital in Paris, during a press briefing on television on March 28, 2020.
What are the signs of seriousness?
WHO distinguishes several clinical syndromes associated with CoV-2-CoRDS: uncomplicated disease, non-severe pneumonia, severe pneumonia, ARDS (acute respiratory distress syndrome), sepsis and septic shock.
In the most severe cases of Covid-19, which require medical management: respiratory signs (difficulty in breathing which can lead to acute respiratory distress syndrome i.e. failure of respiratory functions).
In children: cough or breathing difficulties associated with one of the following signs: cyanosis, acute respiratory distress (whimpering), signs of pneumonia with an alarm sign: drinking or feeding impossible, unconsciousness or convulsions.
Several cases of inflammatory syndromes were reported in Paris in late April-early May, with symptoms similar to Kawasaki disease, in children who had been infected about a month earlier with Covid-19.
The period of contagiousness is thought to be maximal 2-3 days before, and up to 8 days after the onset of symptoms.
What is the incubation period of the disease?
The average incubation period is 4 days with a maximum of 12 to 14 days.
When is it contagious?
Unlike the Sars, Sea or flu viruses, the Sars/Cov-2 virus is contagious even before the onset of symptoms. According to a synthesis of several studies published by Santé Publique France on July 8, the period of contagiousness would be maximum 2 to 3 days before, and up to 8 days after the onset of symptoms.
In addition, about 50% of transmissions would occur during the pre-symptomatic phase of the source patient. Once infected, the patient may remain infected for several weeks.
On the Inter-Resuscitation Collective on Facebook, caregivers report that patients “are still positive after more than 3 weeks of resuscitation”.
→ A virus more contagious than the flu: the transmissibility of SARS-CoV-2 is greater than that of seasonal flu. The R0 (average number of people to whom a patient is at risk of transmitting the disease) is around 3 for this new coronavirus when it is only 1 for seasonal influenza.
The new coronavirus is also highly contagious because it is new and the French population has never been confronted with it.
How long does the disease last?
According to Dr. Gérald Kierzek, “after a fortnight when you have mild symptoms. The recovery is spontaneous except when there is a serious form and you find yourself in intensive care where you need oxygen, where you have pneumonia and then you need to have medication.
Patients in intensive care stay in hospital for a long time, more than 20 days”. Some patients who have not had severe forms also present late symptoms, sometimes after several weeks with a return of fatigue or even shortness of breath when they thought they were cured.
Is one immune when one has had it?
Most likely. “After encountering a virus, our body develops immune defences called antibodies, allowing it to defend itself against it. After infection with coronavirus, we don’t yet know if these antibodies are effective and for how long.
Although we are still at an early stage to decide on this question, in the opinion of the scientists the first data seems reassuring, because to date, no really confirmed case of re-contamination seems to have taken place,”
“One, two, three weeks after an infection confirmed by a positive PCR test, antibodies gradually appear, this is the case in 99% of people who have been tested in different professional environments or in research protocols. These antibodies are protective, which is reassuring”.
How is the testing for the virus done?
There are two types of tests to diagnose Covid-19:
– the so-called PCR test: to detect acute coronavirus infection. It is currently carried out by a specific laboratory technique on a nasopharyngeal swab, the result of which can usually be obtained in 4 hours. No commercial test is available. There are :
- a systematic sampling of the upper respiratory tract (nasopharyngeal/virocult® swabs or aspirations)
sampling of the lower respiratory tract (sputum, BAL, TBA) in case of parenchymal involvement.
- serological test: which detects Covid-19 antibodies in the blood and can tell if you have been infected in the past. These tests can detect the presence of IgM and IgG class antibodies specific for Sars CoV-2 in the serum. They use the ELISA (enzyme linked immunosorbent assay) method on high throughput machines capable of performing hundreds of tests per day. There are also rapid diagnostic orientation tests (TRODs) available in a unitary format, detecting antibodies from a single drop of blood in a few minutes.
What are the treatments?
No treatment has been proven to be fully effective in combating CoV-2 SARS. Numerous clinical trials testing the effectiveness of drugs against the coronavirus are underway.
In mild forms of the disease that do not require hospitalization: in case of fever, it is advisable to take paracetamol and not anti-inflammatory drugs that can make the infection flare up.
It is necessary to monitor the evolution of the symptoms and in case of aggravation with difficulty in breathing, call 15.
If the infection requires oxygen therapy (including low-flow oxygen), hospitalization is necessary.
If there are signs of seriousness, treatment may be considered: use of an antiviral drug (lopinavir ritonavir combination, or even Remdesivir in the most severe cases).
Hydroxychloroquine can no longer be used alone or in combination with a macrolide in the treatment of Covid-19 since 27 May, in accordance with the opinion issued by the High Council of Public Health (HCSP).
In inflammatory forms with acute respiratory distress syndrome (ARDS), treatment options should be discussed on a case-by-case basis.
In an Opinion of 6 June 2020, the HCSP advises against the use of antibiotics in a patient with symptoms associated with a confirmed Covid-19 (outside another infectious site) “due to the exceptional nature of the bacterial co-infection”.
In particular, the antibiotic Azithromycin has been administered to several Covid-19 patients from the beginning of the epidemic. Pending confirmation of the virological diagnosis of Covid-19 and in case of doubt with a bacterial infection, the HCSP indicates that there may be a prescription for amoxicillin.
Increased transmission in confined spaces.
How is the virus transmitted?
The new coronavirus is transmitted between humans mainly through saliva, droplets (coughing, sneezing), by close contact (handshakes…). “It is much more manuporté than we imagined at the beginning,” acknowledged Professor Fontanet on April 30.
It can also be transmitted by contaminated surfaces (coronaviruses survive up to 3 hours on dry inert surfaces and up to 6 days in a wet environment). Regular hand washing (about every hour) and the wearing of masks help to reduce the transmission of the virus.
“To slow down the progression of the virus in the population, we must therefore avoid as far as possible any proximity and contact with others, install a virtual barrier between individuals, and refer scrupulously to the instructions for barrier gestures: respect the distance between individuals, frequent hand washing with soap or hydro-alcoholic gel.
Increased transmission in confined spaces: in an Opinion of June 2, 2020, the Scientific Council Covid-19 insists on the fact that the new coronavirus is transmitted even more in confined spaces.
In these spaces, particles of very small size (<30 m) formed from the evaporation of droplets emitted during speech and theoretically able to contain one or more virions may remain in suspension.
Airborne transmission: respiratory secretions emitted when coughing, sneezing or talking can reach a nearby person (<1 metre) or attach themselves to a surface, such as hands or tissues. Individuals carry the coronavirus, not the air. This is why it is important to respect barrier gestures and social distancing measures.
Transmission via faeces: High Council for Public Health stated in an Opinion issued on 5 March “SARS-CoV-2 can be found in biological fluids including faeces. However, the infectious nature of the virus detected in faeces in some cases is not proven and the risk of faecal transmission has not been documented”.
Animal transmission: At present, there is no evidence that domestic animals such as dogs and cats can spread the virus and/or become infected by humans.
Transmission through water: To date, there have been no reports of contamination through water. “This disease is respiratory and probably animal-to-human, but the source has not yet been identified.”
Prevention: barrier actions to be applied everywhere
Covid-19 is a highly contagious disease. In the absence of truly effective treatments to counter it, prevention consists of respecting several barrier measures.
When will a vaccine be available?
Since the beginning of the coronavirus epidemic in the world, researchers have been working to develop a vaccine against this highly contagious virus. According to the European Medicines Agency (EMA), such a vaccine should not be available before 2021.
Among the avenues being considered is the production of a vaccine based on the measles or BCG (tuberculosis) vaccine.