“The only alternative right now is to use drugs 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, covid-19 disease and whose origin is located in wuhan city, China, is being thoroughly studied by various scientific groups that aim to achieve as soon as possible a drug for their treatment, and maybe later a vaccine that will stop it. On these advances and the characteristics of this coronavirus that keeps the world's big cities paralyzed, speaks in the following interview the academic of the Faculty of Chemical and Pharmaceutical Sciences, Mario Chiong.
Biochemist and PhD in Pharmacology, researcher at the Center for Advanced Chronic Disease Studies (ACCDiS ) and a member of the Department of Biochemistry and Molecular Biology, Mario Chiong, has been involved through ACCDis with the study of Angiotensin Converting Enzyme 2 (ECA2), protein in the human body - which is known today -, the virus recognizes and is anchored in order 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 to the nasal cavity. And that's where it reproduces in cells"., detailed the academic.
Along with knowing the characteristics and how it infects the human body, just over three months after the onset of this new coronavirus, it is also known that it is very similar genetically speaking in sequence to one that has already existed before and that caused the epidemic Acute and Severe Respiratory Syndrome, SARS in 2003, caused by the SARS CoV virus, which had an expansion that lasted eight years and disappeared around 2010, year in which it was completely eradicated from the world.
What was the difference between SARS CoV1 and this new coronavirus?
The main difference is that it produced a disease that was much sharper and more severe, mortality was more than 10 percent, However, because of the severity of the disease, patients quickly developed a picture of respiratory failure that took them to the hospital, and that made the virus not disperse much. On the other hand, the current virus is quite similar, produces the same picture of respiratory failure, but produces a much smoother symptomatology, in fact, there are people who take the picture totally 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 cough with some headaches, with very few people also developing muscle pain, which was the feature that had been announced as the original symptomatology of the virus. This virus by producing a milder disease, or in totally 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 about it?
The only transmission mechanism that is scientifically proven is through saliva droplets, that occur when people cough or sneeze. These droplets disperse through the air, get to the face or hands of people who are close -- we talk about a closeness of a meter, up to a metre and a half, and these droplets that carry the virus, enter people's airways.
It has been described that the virus is also 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, has been found in hospitals where there are sick patients. And samples have been reported that test positive for the virus, i.e., viral particles that are viable and capable of infecting cells in crops, and therefore, are viruses that are potentially infectious.
This virus is one of the viruses that has high 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 listed as highly contagious, why and how does this infect people?
What is known is that when one compares this coronavirus with others, it produces a concentration in the nasal cavity, thousand times higher at least, that the other coronaviruses, in such a way that when a person coughs, releases much more viruses than the others into the environment through saliva droplets, and that explains why it's so contagious.
Then, that virus travels into the bronchial tract and finally reaches the lung, where it infects some of these cells, producing a state of acute inflammation at the pulmonary level. That's where the body in its quest to destroy the virus, mounts a whole immune response against it, but it's not specific, and when trying to destroy the virus it also attacks normal cells. All this exacerbated destruction produces the pneumonia picture that leads to respiratory failure, that when it's very serious it can lead to the patient's death.
The virus receptor enzyme is known to, ECA2, is found in the airways and other areas of the body, what would these be?
In the heart, in the intestine and kidneys. Then, when people get infected, 40 per cent suffer from bowel pictures, because this receptor is in the gut, and also associated with this bowel picture suffer from diarrhoea. This virus also affects the heart, because ECA2 is at people's hearts, in fact the people who have the highest mortality are people who have cardiovascular disease.
In terms of mortality how do comorities and the age of patients affect in the event of contracting the disease?
A healthy person has a 0,0 - 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.
For older adults, have a more diminished immune system and therefore have fewer tools to attack the virus, destroy it and eliminate it. Second, older adults have more comobility, including, high blood pressure is more common in adults, heart failure, diabetes. Due to the increased comorability, older adults are particularly sensitive to the virus attack.
These days two variants of the virus were described in Chile, could you explain what that means?
In Chile there are described two variants: there's one that comes from Wuhan, China, and another whose origin would be European. The enzyme of this virus -RAN polymerase/ dependent RNA- makes mistakes when you make copies, it's not 100 percent trustworthy. Then, when you make a mistake, the original virus is no longer the same as the new virus. That doesn't mean the modification is going to change the infectivity of the virus, because a lot of those changes are silent, don't cause a change in the structure of the virus, but they are used as a marker of phylogeny, to see where the virus comes from.
What are different variants, don't you mean, for example, that there is one more lethal than another or that we would have to look for different drugs for the treatment of each?
We don't know. For other coronaviruses, for example, many of its variants occur unchanged in the protein structure of the virus, Therefore, have no effect on their infectivity or their resistance, but simply realizes a genetic variability of the virus to do a global distribution analysis. Now, might have some effect.
In terms of medicines to treat patients, and given this great similarity to SARS CoV1, are you looking for drugs that were previously used for that virus?, how possible is it to find a drug to treat the virus in the short term?
All the drugs being tested had now shown activity against SARS. The problem is that this virus is not exactly the same, then you have to repeat all the rehearsals.
WHO is currently leading a study, called Solidarity Study, looking to test four drugs globally, And these are: Chloroquine and Hydroxychloroquine, Remdesivir - used for Ebola-, the other is a mixture of two drugs used at the start of HIV treatment, Ritonavir-Lopinavir, and the fourth is the Interferon Beta, which is an immune response stimulator, that in this study will be used in combination with Ritonavir-Lopinavir.
We're against the clock., this is a new virus and it's impossible to think about designing a new drug in months, the only alternative 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 if in patients it will work, the same thing the mixtures that were tested also worked in vitro, we have to see if in patients it will work, that's what you intend to do in this study
And are the chances of a vaccine still far away?
The first thing to do in such cases is to show that the vaccine is 100 percent safe, and for that you have to take healthy people, put the vaccine on them and prove that that vaccine does nothing in those people. Those studies are now being done, but they don't prove that the vaccine is effective. To show that it is 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..
Regarding the isolation measures that have been taken in the country to slow the advance of the virus, should we continue to make progress on greater restrictions?
That's right. If you wanted to get strict, we should get to the "Chinese Method", which is total and strict quarantine to stop the disease, it's proven to work. But that's going to bring with it a number of economic consequences for the country, and we're not a rich country, then, since there are things that can't be done is that we're in an intermediate situation, trying to control the focus of the disease through localized quarantines.
Regarding the exam, which is another important measure taken by countries where strategies have been successful, is it too expensive?, does it require a lot of technology or human resource that we don't have?
There are two types of tests that are currently available for coronavirus, one that is the universally accepted, which is the PCR, which detects the genetic material of the virus. This test can 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. How detection is so sensitive, is very susceptible to which the sample is contaminated, it's not a regular test. In addition, the method is not instantaneous, takes hours.
The other method - the quick test- is to detect the antibodies, that the body manufactures against the virus, but it takes four to six days for the human body to manufacture the antibodies, and, Therefore, when the person testes 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 the conduct of tests, do you know right now how many PCR exams can be done today in Chile?
The data that specialists handle are as follows: the public system could or is making the order of 3,800 and are operating relatively at full capacity, and this we're talking about Arica to Punta Arenas. However, to this basic network, public institutions have now been added, universities and research centres, who have the equipment and also the staff who know how to use the equipment and that could raise the amount of analysis by about 5 thousand more tests daily. Chile would be currently able to do about 8,000 to 8,500 PCR tests per day. However, not all teams in public institutions are being used for analysis, because there is a logistical problem of access to these equipment and the inputs that need to be had to get them going. Chile is not a manufacturer of these inputs, you have to import them all.
Regarding the test rate compared to other countries, would that amount of testing be enough?
I'd say with 8 grand we're on a good footing.
Finally, mortality in relation to this virus is also known to depend - among other things- the ability of health systems to treat patients in a timely manner. What is the picture you see in the Chilean case?
I'm going to be optimistic in this response. All the measures currently being taken at the government level aim to try to reduce cases of new contagion, to try to flatten the curve of the disease, try to make them the least daily cases. At no point do I think we're going to slow him down., but it does significantly decrease the number of new cases, so that the total number of cases is never greater than the maximum number of available beds we have. If we get to that ideal condition, we will be able to care for all coronavirus patients who need urgent clinical care. If that happens, our mortality rates should be maintained in the order of the world level. Not more than 3 percent.
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