Death rate, i.e. the number of deaths reported in the general population from Covid-19 disease is 0,15% as of April 8, 2021. A rate three times higher than seasonal flu, according to Inserm. The case fatality rate (the number of deaths compared to the number of cases) is 2,5% (as of December 23). The weekly rate of Covid-19-related death was 1,9 per 100 population in week 19. Even if we lack perspective on this new coronavirus, statistics show that certain populations are more at risk than others.

If the Covid-19 claims so many victims, it is because it is a new virus against which no one was immune, unlike the flu. “This means that more people are vulnerable to infection and some will develop a severe form,” says Tedros Adhanom Ghebreyesus, director of WHO.

The risk of developing a severe form of the disease is also greater in Covid-19 than in seasonal flu. Hence the urgency to find effective treatments and a vaccine against the new coronavirus.

The epidemic having started in China, scientific research on the characteristics of the new coronavirus is more advanced than elsewhere. Several Chinese studies have been able to establish profiles of people most likely to develop a severe form of the disease and die from it.

A study published in The Lancet on March 9, 2020 and conducted on 191 hospitalized patients, indicates that the deceased patients (54) were older than those who survived (69 years on average among the victims against 52 years among the survivors). This same study also shows that among those who died, almost half (48%) suffered from another disease: hypertension, diabetes or coronary heart disease.

People with chronic respiratory disease (such as COPD), cancer, or chronic kidney disease are also more likely to develop a severe form of the disease that can lead to death.

Another larger Chinese study based on more than 72 Chinese patients (all cases recorded in China as of February 000, 11) made it possible to establish the typical profile of victims of Covid-2020. Again, the figures show that mortality increases with age. These studies report that those over 19 have a 80% risk of dying from the new coronavirus, the rate drops to 15% in those in their seventies and then to 8% in those in their sixties. This survey shows that 3,6% of patients who died from Covid-80 were over 19 years old and more than half (60%) were men.

In France, the figures confirm this trend since only 7% of deceased people were under 65, said Professor Jérôme Salomon, Director General of Health, in his situation report of March 17, 2020.

The Chinese Center for Disease Control and Prevention (CCDC) survey reveals that the death rate is lower among those under the age of 60. He’s from :

• 1,3% among XNUMX-year-olds;
• 0,4% in the XNUMXs;
• 0,2% among those under 40.

According to the latest report from Public Health France, dated May 21, 2021, here is the breakdown of the deceased according to their age:

• less than 1% between 0 and 14 years old;
• less than 1% between 15 and 44 years old; 
• 8% between 45 and 64 years old;
• 17% between 65 and 74 years old;
• 74% for those 75 and over. 

These figures are less alarming than for those over 60, but it still shows that Covid-19 also kills young people. If we compare the new coronavirus to the seasonal flu, we notice that it kills more young people than the flu. “It is not a flu, it can give serious forms on people not so old as that and not suffering from chronic pathologies”, indicated Professor Jérôme Salomon, during the daily situation update given on March 10, 2020.

We remember a young case publicized in China: Dr. Li Wenliang. This ophthalmologist had given the alert on the coronavirus at the end of December 2019. Himself affected, he died on February 7, 2020 in Wuhan, at only 33 years old. Another young case is the first patient infected in Italy, “patient 1”. This is Mattia, a 38-year-old athletic man who was in good health before the infection. Mattia was admitted to the intensive care department of the polyclinic in Pavia (Lombardy) in mid-February. He had developed a severe form of the disease. Put under artificial respiration for three weeks, the man recovers slowly.

On May 19, 2020, a death of a 9-year-old child is to be deplored in France among the victims of Covid-19. Nevertheless, the data published by the French Pediatric Society (SFP) and based on several studies, show that children are relatively spared from the disease. The CCDC survey cited above and conducted on the first Chinese patients (more than 72) showed that among them, only 000% were children and adolescents under 2 years. Another Chinese study carried out on 19 children under 9 year of age hospitalized for Covid-1 indicates that none presented with a complication of the disease. Unicef ​​recalls that among the first 19 Italian cases, 8400% were between 0,5 and 0 years old, and 9% were between 1 and 10 years old.

In the vast majority of cases, children who tested positive for the virus had mild symptoms, if any (asymptomatic). Which is not to say that they are not contagious. They can pass the disease on to other people. Hence the interest of confinement for all and respect for barrier measures. 

MIS-C or PIMS syndrome and Covid-19 in children 

In April 2020, 25 sick children were admitted to the intensive care unit at Necker hospital in Paris. They were taken to the emergency room with inflammatory symptoms affecting the heart, lungs and digestive system. These syndromes were reminiscent of those of rare Kawasaki disease. Today, researchers have declared the onset of post-Covid inflammatory syndrome in her children, called MIS-C syndrome (multisystem syndrome) or PIMS for pediatric multisystem inflammatory syndromes. Since then, France has counted 501 cases of children presenting these clinical signs and more than a thousand in the world. A young boy aged 9 from Marseille has died. He suffered from co-morbidity and responded positively to the Covid-19 test. There could therefore be a correlation with Covid-19 infectionbecause the majority of these children have tested positive. The Minister of Health, Olivier Véran, said to himself worried. However, no scientific evidence is asserted. To confirm or not the existence ofa link between PIMS and coronavirus in children, professional teams of caregivers and researchers are mobilized to obtain as much data as possible. This inflammation is still rare and it is for this reason that scientists lack information. 

What about pregnant women and infants?

Update November 23 – Women in the third trimester of pregnancy are among those vulnerable and at risk of developing severe forms of Covid-19. Teleworking is recommended for them. 

We have little data on the consequences of infection during pregnancy. Two Chinese studies carried out on 18 infected pregnant women show that infected pregnant women have the same symptoms as other women. Of the 18 pregnant women (including one of twins) infected, 16 gave birth by caesarean section, 6 babies were in fetal distress and 6 gave birth prematurely. These low figures do not make it possible to state whether or not Covid-19 during pregnancy can be dangerous for both mother and baby. As a preventive measure, pregnant women must be particularly vigilant and protect themselves as much as possible against the virus, just like the most vulnerable populations (the elderly and those suffering from co-morbidities). The Chinese authorities also recommend systematic screening in pregnant women.

So far, 1 single case of transmission of the virus from mother to fetus or newborn (during pregnancy and during childbirth) has been recorded.

According to a study by Chinese researchers at the University of Shenzhen, people with blood group 0 are 33% less likely to have coronavirus. Conversely, people wearing group A would be more at risk with 20% more attack.

Thus, in the report of Chinese researchers, belonging to a particular blood group could be a risk factor in reaching Covid-19. The statistical study, published in the scientific journal “MedRxiv”, specifies that:

• People in group O would have a 33% lower risk of being infected with Covid-19 compared to people in groups B and AB.
• People in group A would have a 20% increased risk of being infected with Covid-19 compared to people in groups B and AB. 

Note that the two hypotheses put forward by these researchers are effective regardless of the sex or age of the individual studied.

A scientific explanation

Jacques Le Pendu, research director of Inserm, at the cancerology and immunology research laboratory in Nantes-Angers, explains that “This result is not surprising. We found the same thing in a 2003 study of the SARS virus outbreak «.

Already in 2008, a start to the track had been proposed in a French study, published in Glycobiology, in which Jacques Le Pendu had participated. Indeed, depending on our blood type, the blood will develop different antibodies.

Thus, in people in group 0, all rhs combined, the plasma that makes up the blood has anti-A and anti-B antibodies: therefore a better defense against viruses, including that of the new coronavirus. On the contrary, for people in group 1, the plasma contains only one type of antibody (anti-B): which would then explain a single defense against the virus.

According to a study by Chinese researchers at the University of Shenzhen, people with blood group 0 are 33% less likely to have coronavirus. Conversely, people wearing group 1 would be more at risk with 20% more attack.

Thus, in the report of Chinese researchers, belonging to a particular blood group could be a risk factor in reaching Covid-19. The statistical study, published in the scientific journal  MedRxiv , specifies that :

• People in group O would have a 33% lower risk of being infected with Covid-19 compared to people in groups B and AB.
• People in group A would have a 20% increased risk of being infected with Covid-19 compared to people in groups B and AB. 

Note that the two hypotheses put forward by these researchers are effective regardless of the sex or age of the individual studied.

The results of two new scientific studies were published on October 14 in the journal Blood Advances. They provide some details on the link between blood group and the severity of the coronavirus infection. The first study was carried out on 473 people who tested positive for Covid-000. Patients with O or B blood spent less time in an intensive care unit than their type A or AB counterparts. They also needed less mechanical breathing and dialysis. The second study, conducted on 19 patients with severe Covid-95 in a hospital in Canada, between February and April 19, showed that patients with type O or B blood group spent an average of 2020 days less intensive care, than those with type A or AB blood, who stayed there for an average of 4,5 days. 

A scientific explanation

Jacques Le Pendu, research director of Inserm, at the cancerology and immunology research laboratory in Nantes-Angers, explains that “This result is not surprising. We found the same thing in a 2003 study of the SARS virus outbreak «.

Already in 2008, a start to the track had been proposed in a French study, published in Glycobiology, in which Jacques Le Pendu had participated. Indeed, depending on our blood type, the blood will develop different antibodies.

Thus, in people in group 0, all rhs combined, the plasma that makes up the blood has anti-A and anti-B antibodies: therefore a better defense against viruses, including that of the new coronavirus. On the contrary, for people in group 1, the plasma contains only one type of antibody (anti-B): which would then explain a single defense against the virus.