Academic Mario Chiong on possible treatments for Covid-19: "The only alternative right now is to use medicines that already exist to see if they have effects on this virus"

Academic Mario Chiong on possible treatments for Covid-19: "The only alternative right now is to use medicines that already exist to see if they have effects on this virus"

Nearly one million infected and more than 50,000 deaths have left the coronavirus, SARS Cov2, around the planet. The new virus, which causes Covid-19 disease and whose origin is located in the city of Wuhan, China, is being thoroughly studied by various scientific groups that aim to get a drug for treatment as soon as possible, and perhaps later a vaccine that manages to stop it. About these advances and the characteristics of this coronavirus that keeps the world's big cities paralyzed, the academic of the Faculty of Chemical and Pharmaceutical Sciences, Mario Chiong, speaks in the following interview.

Biochemist and Doctor of Pharmacology,researcher at the Center for Advanced Studies of Chronic Diseases (ACCDiS)and a member of the Department of Biochemistry and Molecular Biology, Mario Chiong, has been involved through ACCDis with theangiotensin 2(ECA2) Enzyme, a protein in the human body - now known- the virus recognizes and is anchored to act. "In the nasal cavity there are cells that are very abundant in this protein. Therefore, when the virus is inhaled by people, the first place it reaches is the nasal cavity. And that's where it breeds in cells," the academic said.

Along with knowing the characteristics and how it infects the human body, just over three months after the emergence of this new coronavirus, it is also known thatit is very genetically similar by speaking in sequence to one that already existed before and that caused the epidemic Acute and Serious Respiratory Syndrome, SARS in 2003,caused by the SARS CoV virus, which had an eight-year expansion and disappeared around 2010, when it was completely eradicated from the world.

What difference did SARS CoV1 make to this new coronavirus?

The main difference is that it produced a disease that was much more acute and severe, mortality was more than 10 percent, however, due to the severity of the disease patients quickly developed a breathing failure frame that took them to the hospital, and that caused the virus not to disperse much. In contrast, the current virus is quite similar, it produces the same picture of respiratory failure, but produces a much milder symptomatology, in fact, there are people who take the picture completely asymptomatic.

In Chile, for example,according to the analysis of the first 900 cases, it is shown that only 9 percent of these people develop fever, half develop coughing with some headaches, with very few people also developing muscle pain, which was the feature that had been advertised as the original symptomatology of the virus. This virus by producing a milder disease, or in fully asymptomatic cases, makes its dispersion much higher, and that makes it very difficult to control.

In terms of transmission there is a lot of information circulating, what are we sure about today?

Thethe only transmission mechanism that is scientifically proven is through saliva droplets,that occur when people cough or sneeze. These droplets disperse through the air, reach the face or hands of the people who are close - we speak of a close one meter, up to a meter and a half - and these droplets that carry the virus, enter the airways of people.

The virus has also been described as being found in the faeces and urine of infected people, but to date it has not been described that these can be contaminated through these mechanisms. The virus has also been detected on surfaces that have been in contact with sick people, for example, it has been found in hospitals where patients are sick. And samples have been reported that test positive for the virus, i.e. viral particles that are viable and that are able to infect cells in cultures, and therefore, are viruses that are potentially infectious.

This virus is one of the viruses that has great resistance on surfaces. In steel, plastic and glass, the virus can last between 24 and 72 hours depending on environmental conditions. And these are infective viral particles.

This virus is classified as highly contagious, why and how does it infect people?

What is known is that when you compare this coronavirus with others,it produces a concentration in the nasal cavity, a thousand times higher at least,than the other coronaviruses, so that when one person coughs, it releases much more viruses than the others into the environment through saliva droplets, and that explains why it's so contagious.

That virus then travels into the bronchial tract and eventually reaches the lung, where it infects some of these cells, producing a state of acute inflammation at the lung level. That's where the body in its quest to destroy the virus, mounts an entire immune response against it, but it is not specific, and by trying to destroy the virus it also attacks normal cells. All this exacerbated destruction produces the picture of pneumonia that leads to respiratory failure, which when it is very severe can lead to the death of the patient.

The virus's receptor enzyme, ECA2, is known to be in the airways and other areas of the body, what would these be?

In the heart, intestine and kidneys. Thenwhen people become infected, 40 percent suffer intestinal pictures, because this receptor is in the gut, and also associated with this intestinal picture suffer diarrhoea. This virus also affects the heart, because ECA2 is at the heart of people, in fact the people with the highest mortality are people who have cardiovascular disease.

In terms of mortality how do comorities and age of patients affect in the event of contracting the disease?

A healthy person has 0.2 or 0.3 percent mortality,instead, a person who has cardiovascular disease, mortality rises to 15 percent.In people who have asthma or other respiratory diseases, mortality rises to 5 percent.

In the case of older adults, they have a more decreased immune system and therefore have fewer tools to attack the virus, destroy it and eliminate it. Second, older adults have more comorities, including high blood pressure is more common in adults, heart failure, diabetes. Due to the increase in comorities older adults are particularly sensitive to attack of the virus.

These days two variants of the virus were described in Chile, could you explain what that means?

In Chile there are two variants described: there is one that comes from Wuhan, China, and another whose origin would be European.The enzyme in this virus -RAN polymerase/ dependent RNA - makes mistakes when making copies, is not 100 percent reliable. So, when you make a mistake, the original virus is no longer the same as the new virus. That doesn't mean that the modification will change the infectivity of the virus, because many of those changes are silent, they do not produce a change in the structure of the virus, but they are used as a marker of phylogeny, to see where the virus comes from.

Just because they're different variants, doesn't that mean, for example, that there's one more lethal than the other or that we'd have to look for different drugs for the treatment of each?

We don't know. In the case of other coronaviruses, for example, many of its variants occur without changes in the protein structure of the virus, therefore they have no effect on their infectivity or resistance, but simply results in a genetic variability of the virus to perform a distribution analysis at a global level. Now, it could have some effect.

In terms of drugs to treat patients, and given this great similarity to SARS CoV1, are drugs that were previously used for that virus looked upon, how much is it possible to find a drug to treat the virus in the short term?

Allthe drugs being tested had now shown anti-SARS activity. The problem is that this virus is not exactly the same, then all rehearsals must be repeated.

WHO is currently leading a study, called the Solidarity Study, which seeks to test four drugs worldwide, and these are: Chloroquine and Hydroxychloroquine, Remdesivir -used for Ebola-, the other is a mixture of two drugs used at the beginning of HIV treatment, Ritonavir-Lopinavir, and the fourth is Interferon Beta, which is an immune response stimulator, which in this study will be used in combination with Ritonavir.

We're on the clock, this is a new virus and it's impossible to think about designing a new drug in months,the only alternative that the scientific community has right now is to use drugs that already exist to see if it has effects on this virus.The Remdesivir used for Ebola was tested in vitro and worked, what is not known is whether in patients it will work, the same the mixtures that were tested also worked in vitro, we have to see if in patients will work, that is what is intended to do in this study

And are the chances of a vaccine still a long way off?

The first thing to do in these types of cases is to show that the vaccine is 100 percent safe, and for that you have to take healthy people, give them the vaccine and show that that vaccine does nothing in those people. These studies are being done now, but they do not show that the vaccine is effective. To prove it's effective, you have to take people who are susceptible to getting sick, give them the vaccine and wait to see if they get sick or not, and that compare it to another group that hasn't received the vaccine. That's going to take months.

With regard to the isolation measures that have been taken in the country to slow the progress of the virus, should we continue to move forward with greater restrictions?

That's right. If one wanted to get strict, we should get to the "Chinese Method", which is total and strict quarantine to stop the disease, which is proven to work. But that is going to bring with it a number of economic consequences for the country, and we are not a rich country, so, since there are things that cannot be done is that we are in an intermediate situation, trying to control the floodlights of the disease through localized quarantines.

With regard to the review, which is another important measure that countries have taken where the strategies have been successful, is it very costly, does it require a lot of technology or human resource that we do not have?

There are two types of tests that are currently available for coronavirus, one that is universally accepted, which is thePCR, which detects the genetic material of the virus. This test allows to detect fully asymptomatic people, people who are carriers of the virus, even before developing symptomatology.The problem is that it requires a computer is not cheap and an infrastructure that is not common. Because detection is so sensitive, it is very susceptible to the sample being contaminated, it is not a regular test. Also, the method is not instantaneous, it takes hours.

The other method - the rapid test - is to detect the antibodies, which the body manufactures against the virus, but the human body takes four to six days to make the antibodies, and therefore when the person tests positive is because the person was sick six days ago.

Considering that it is critical to test and that there are questions to the figures that are given on testing, do you know at this time how many PCR exams can be done today in Chile?

The data that specialists handle are as follows: the public system could make or is doing in the order of 3,800 and is operating relatively at full capacity, and this we are talking about Arica to Punta Arenas. However, to this basic network, public institutions, universities and research centres have now been added, which have the equipment and also the staff who know how to use the equipment and that could increase the amount of analysis by about 5 thousand more daily tests. Chile would currently be able to do about 8,500 pcR analyses per day. Howevernot all equipment in public institutions are being used for analysis, because there is a logistical problem of access to those equipment and the inputs that need to be made to set them up. Chile is not a manufacturer of these inputs, it has to import them all.

With regard to the test rate compared to other countries, would that amount of testing be sufficient?

I'd say at eight grand we're on a good foot.

Finally, it is known that mortality in relation to this virus also depends - among other things - on the ability of health systems to care for patients in a timely manner. What is the picture you see in the Chilean case?

I'm going to be optimistic in this answer. All the measures currently being taken at the government level aim to try to reduce new cases of contagion, to try to flatten the disease curve, to try to make them the least daily cases.At no point do I think we're going to slow it down, but yes greatly decrease the number of new cases,so that the total number of cases never exceeds the maximum number of available beds we have. If we reach that ideal condition, we will be able to care for all coronavirus sufferers who need urgent clinical care. If that happens, our mortality rates should be kept in the order of the world level. Not more than 3 percent.

Source: www.uchile.CL