What we know about the ‘tortuous’ coronavirus

PARIS, France – Will the new coronavirus take your breath away or will you lose your sense of smell? And if you’ve had it once, can you be sure it’s immune? So far, the COVID-19 investigation has raised as many questions as it has answered.

The tiny pathogen, which is enriched with proteins that scientists think it uses to attach itself to the host cells of its victims, is surprisingly slippery.

“This virus is an unpleasant job,” says Jean-Francois Delfraissy, a specialist who helps France with its COVID-19 response.

This is what we know so far:

WHO IS MORE AT RISK?

There is increasing data to suggest that the severity of COVID-19, the disease caused by the SARS-CoV-2 virus, increases with age.

Recent research, mainly focused on several hundred cases observed in China in late February, suggested that the disease is on average much more dangerous for people over the age of 60, a group that has a 6.4 percent death rate. among confirmed cases.

But this goes up more than older patients, with 13.4 percent of cases over the age of 80 leading to death, versus just 0.32 percent for those under 60.

The study, which was published in the British medical journal The Lancet on March 31, also said that the proportion of people with COVID-19 needing hospital care increased significantly with age, while just 0.04 percent of young people in 10 to 19 years required hospitalization. , which increased to 4.3 percent for those in their forties.

And nearly one in five 80-year-olds with the disease (18.4 percent) developed a form severe enough to require hospital treatment.

Chronic diseases can also increase the risk.

In a report analyzing 20,000 deaths, the Italian National Institute of Health (ISS) found that the most common underlying health problem was hypertension, seen in 69.7 percent of cases, followed by diabetes in 32 percent, and coronary heart disease at 27.7 percent.

Finally, according to a large analysis published in February by Chinese researchers in the American medical journal JAMA, the disease is mild in 80.9 percent of cases, severe in 13.8 percent, and critical in 4.7 percent.

How many deaths?

If you compared the number of deaths in the world with the total number of officially registered cases, you could conclude that COVID-19 kills approximately seven percent of diagnosed patients, depending on the country.

But this number must be taken with caution: it is unclear how many people have been infected.

Many people seem to develop few or no symptoms and for the most part are not counted in official figures, and countries adopt markedly different approaches to testing and many do not follow up on each suspected case.

If official counts included milder case numbers, the death rate would likely be significantly lower.

With those aggregate undetected cases “that will likely reduce death rates to about one percent,” said chief scientist of the United States government, Anthony Fauci, in comments to Congress.

“Which means it is 10 times more lethal than seasonal flu,” he said.

“This is a really serious problem that we must take seriously.”

The dangerousness of a disease depends in part on its ability to spread. Even a one percent death rate can translate into a significant number of deaths if the disease affects a large proportion of the population.

Pressure on hospitals caused by a large influx of patients has also exacerbated the cost of COVID-19.

WHAT ARE THE SYMPTOMS?

The World Health Organization lists the most common symptoms such as fever, fatigue, and dry cough.

But he says some patients may experience a variety of other ailments, from a runny nose to diarrhea.

The virus can often cause difficulty breathing, which in more severe cases can lead to respiratory failure.

It is also increasingly clear that the coronavirus can affect the brain and nervous system.

Field observations and several studies have described neurological symptoms: loss of smell and taste, nervous pain, confusion, including seizures and strokes.

This could be due to a phenomenon known as a “cytokine storm,” a rapid overreaction of the immune system.

There is no vaccine or medication, and management involves treating symptoms. However, some patients have received antiviral medications or other experimental treatments, as scientists seek treatments.

HOW IS IT TRANSMITTED?

The virus is spread primarily through respiration and physical contact, and it appears that a patient can already be contagious even before the first symptoms appear.

Respiratory transmission occurs through droplets of saliva expelled by an infected person, for example in a cough. Scientists believe this would require close contact, at a distance of about one meter (three feet).

You could also become infected by touching a contaminated object and then putting your hand to your face.

Two studies, one published in mid-March and the other in mid-April, in the US New England Journal of Medicine. USA They found that the new coronavirus is detectable for up to two or three days on plastic or stainless steel surfaces, and up to 24 hours in cardboard

However, these maximum durations are only theoretical.

“These studies have evaluated the presence of genetic material, and not a live virus,” French health authorities said, adding that the virus’s ability to contaminate decreases very rapidly abroad.

Another unknown is the ability of the virus to circulate in the air, what scientists call an aerosol, and contaminate itself in this way.

To prevent the spread, the health authorities have emphasized the barrier measures: avoid shaking hands and kissing, wash your hands frequently, cough or sneeze in the elbow socket. And wear a mask if you are sick.

CAN IT BE INFECTED TWICE?

South Korea has recorded cases of patients who apparently recovered and tested negative, then tested positive again, raising questions about whether it could contract the virus twice.

The most commonly accepted assumption is that these patients never really recovered. Its negative result could be explained either by a very low presence of the virus in the body, or by the fact that the test was poorly performed.

But the degree of immunity for those who have had the disease is still far from true.

French coronavirus adviser Delfraissy said the virus was “deviant,” and told a recent parliamentary committee that some evidence suggested the possibility of “reactivation.”

He wondered “if we are not completely wrong” by relying on the idea of ​​immunity.

But if that were the case, it would be extremely difficult to control the epidemic because people could be repeatedly infected.

pr / klm / dl

© Agence France-Presse