Note: This text is an extract of Coronavirus Infection (see the source to read the whole article and for a link to reference numbers).
What science says about Coronaviruses
Coronaviruses are a large family of positive sense RNA single-stranded respiratory viruses. They have a diameter of about 80-160 nm (1 nanometre is a millionth of a millimetre) and their genome is among the longest of the RNA viruses (it has about 30,000 nitrogen bases).
The name “coronavirus” derives from their appearance under the electron microscope, where the bulbous-shaped proteins placed on their external surface create a crown image. These proteins are precisely those that allow the virus to attach to the cell membrane of the cells that they will then infect. Subsequently, the virus penetrates inside the cell, forcing it to encode its RNA, the proteins of the external envelope and therefore the whole virus which will then exit the cell to infect other cells and so on (1).
The common Coronaviruses are responsible for pathologies in mammals and birds, in which they cause diarrhea (cows and pigs) or diseases of the respiratory tract (chickens).
In humans, common Coronaviruses often cause respiratory infections such as the common cold, but, in some cases, they can cause non-serious viral pneumonia (normal Coronaviruses are responsible for about 20% of all viral pneumonia), but rarely can also cause a Severe Acute Respiratory Syndrome (SARS).
As has happened with other viruses, some animal-specific Coronaviruses, which normally do not infect our species, can make a “species jump” and pass to humans, thus causing very serious and occasionally life-threatening pneumonia.
In this case, the severity of the pathology depends on the fact that, if the virus is new, our immune system does not know it because it has never come into contact with it, it cannot defend itself and suffers an attack which becomes particularly violent and dangerous in immunologically weak or immunosuppressed subjects, especially the elderly with important chronic diseases or other subjects weak in the immune, cardiopulmonary, renal or metabolic level.
Today we know 7 human Coronaviruses. The first 4 of the following list are very common (they are also called “cold viruses”) and were identified in the 1960s, while the last 3 have been identified in the last few years:
- Human Coronavirus 229E (Coronavirus alpha).
- Human Coronavirus NL63 (Coronavirus alpha).
- Human Coronavirus OC43 (Coronavirus beta).
- Human Coronavirus HKU1 (Coronavirus beta).
- SARS-CoV (Coronavirus beta that caused the Severe Acute Respiratory Syndrome of 2002, an epidemic from China that infected about 8,100 people, among which it caused a mortality of 9.5%)
- MERS-CoV (Coronavirus beta that caused the Middle East Respiratory Syndrome of 2012, an epidemic from Saudi Arabia that infected about 2,500 people, among which it caused a mortality of 35%).
- CoVID-19 (new Coronavirus from late 2019 that is causing severe acute respiratory syndrome which can lead to death in a small minority of cases; the outbreak / pandemic started in Wuhan, a city in China, where it infected about 100,000 people causing an estimated mortality of 2.3% so far: 1,023 deaths out of 44,672 confirmed Chinese cases) (2) (for updated world data see bibliography 3 and for updating Italian data see bibliography 4).
CoVID-19 has been called “new Coronavirus” because it is a new strain of Coronavirus that has never been previously identified in humans. The virus is associated with an outbreak of pneumonia cases registered as of December 31, 2019 in the city of Wuhan (central China). It seems, but it is not certain, that most of the cases initially had an epidemiological link with the market of Huanan Seafood (southern China), a wholesale market for seafood and live animals.
Initially COVID-19 was called Coronavirus 2019ncov. Because of this earlier name, some people mistakenly think there are two strains involved in the current situation.
In fact, CoVID-19 is 96% genetically identical to a known Coronavirus of bats and 86-92% to a pangolin Coronavirus. Therefore, the transmission of a mutated virus from animals to humans is the most likely cause of the appearance of this new Coronavirus.
Will the virus mutate?
There is, of course, a concern about this. Scientific and medical authorities have stated that this coronavirus does not appear to be mutating. The fact that the number of cases in China is decreasing supports this view.
How the infection is transmitted
Human Coronaviruses are transmitted from one infected person to another mainly through direct contact with saliva, coughs and sneezing (you must be within a range of about 1-1.5 meters), but probably also through direct contact with the nasolabial mucous membranes or the hand of a patient (the patient is likely to have contaminated hands, because it is easy to touch the nose or put it in front of the mouth when coughing or sneezing) (5).
In fact, in China, the main cause of infection (78-85%) occurred within the family and in particular due to aero-transmitted droplets from carriers of infection that place themselves in close contact with a person. Transmission in the air over long distances (over 1.5-2 meters), especially if in large environments or outdoors, is not an important cause of diffusion (6).
According to data released by the WHO to date (6), it appears that if you have direct personal contact with an infected person, the probability of infection is not absolutely high, because it is only 1-5%.
Obviously, in the latter case, anyone who has been touched by the hand of a patient is at risk of getting sick only if he puts his hand in his mouth or if he touches the mucous membranes of the nose and eyes before washing his hands thoroughly.
A patient can spread viruses during the symptoms of the disease but, as with all viruses, he can also do so in the 5-6 days preceding the clinical manifestation of the symptoms (probably also in the previous 15 days) and therefore before it is discovered that he was really infected.
Why the cases of infected people are multiplying?
First of all I think it is correct to thank our Government, the Ministry of Health and the Interior, the Civil Protection and the various Regional Governors, because they worked together from the first news that arrived from China in late January and quickly made courageous decisions, not implemented by all other countries, to multiply pharyngeal swabs and limit the extent of the epidemic.
Given that in Italy the swab was also made to all the people who came into contact with individuals who tested positive and that this, at least for now, is not performed in other European States, it is obvious that in our country it is easier to find many cases of infected people.
It is therefore obvious that Italy in the last few days has become the most affected European country and with a number of cases similar to that of Hong Kong (3).
It is possible that in a few days the same will happen in the rest of Europe, but for now we are the first in this bad ranking.
If we have to look positively at this reality, it must be said that this position of our country should allow us to stem the infection by immediately isolating the outbreaks of the disease. However, we must be careful not to create too much alarm and not to exaggerate, because I would not want the Coronavirus infection to become more than a danger / health damage, a real danger / economic damage!
And if someone wonders why there are still so many infected people, I would suggest reflecting on the objective fact that today interregional, international and intercontinental travels and journeys are very common and very frequent and there are many people who, for work or other reasons, meet in a few days, tens and hundreds of people.
The symptoms of Coronavirus infection
The most common symptoms in humans are: malaise, asthenia, cold, headache, fever, pharyngitis and cough. In severe cases, the infection can cause pneumonia with severe acute respiratory distress, kidney failure and rarely death (5).
The problem is that we are still in the period in which there is also the common flu syndrome which, as we know, is caused by the actual flu virus but also by many other viruses that cause completely overlapping symptomatologic pictures, at least in the first days in which the symptoms of Coronavirus infection appear.
Differential diagnosis is difficult and is only allowed with certainty by the microbiological examination of a sample taken with the pharyngeal swab and using the PCR (Polymerase Chain Reaction) technique, an examination that provides the result in only 2-3 hours.
However, I believe that if in a few days not only the results of positive swabs from Coronavirus infection multiply, but also the deaths due to pathology from Chinese Coronavirus CoVID-19, then, given that the latter is much more infectious than our normal Coronaviruses , an extension of the infection is likely to occur in Italy too.
CoVID-19 Coronavirus mortality
Seasonal flu syndrome mortality (NOT from actual flu virus) is said to be around 7,000 people per year in Italy.
According to InfluNet (the national epidemiological and virologic surveillance system of influenza, coordinated by our Ministry of Health with the collaboration of the Istituto Superiore di Sanità (Italian equivalent of US Centers for Disease Control), influenza syndrome affects approximately 6-8 million people every year, i.e. 9% of the population.
In Italy, influenza viruses directly cause approximately 300-400 deaths each year, with about 200 deaths from primary viral pneumonia, however, according to the estimates of the various studies, these deaths must be added 4-8,000 “indirect” deaths caused by pulmonary (bacterial pneumonia) or cardiovascular (heart failure) complications of influenza.
The numerous viruses that cause seasonal flu syndromes can in fact create complications especially in the elderly or in any case in all people who before suffering from the flu were already suffering from serious chronic diseases or immunodeficiencies.
Therefore, it is estimated that our seasonal flu mortality rate (i.e. the ratio of dead to infected) is less than one per thousand, that is 0.1%.
If we now compare with the new Coronavirus, one might ask: our seasonal flu syndrome is more dangerous than CoVID-19 infection, considering that only in Italy the deaths for the first are higher every year than those recorded so far in China because of the new virus?
In general, the answer, which for now is based only on provisional data, should be “YES” because it is true that the mortality of CoVID-19 seems to be around 2.3% and therefore greater than that of the flu syndrome, but the latter affects millions of people and therefore ultimately causes more deaths.
However, I do not know if it is a sure answer, because it is still far too early to draw conclusions: they are highly provisional data since we do not know the exact number of people infected with CoDIV-19, which is likely to be a higher number (many people who are poorly symptomatic and therefore have not been registered).
The substantial difference between flu viruses and Coronaviruses is that: while the normal viruses that cause seasonal flu syndrome are known to our body and cannot infect the whole population because many people are already immunized (because vaccinated or because already protected by natural antibodies formed from previous contacts), this new Coronavirus is unknown to our immune system, therefore it obviously finds people immunologically unprepared and therefore it can spread much faster (as it seems it is doing in this last period) and can also cause serious damage, which occur in a higher percentage but within fewer people.
In any case, we have to wait another 1-2 months for more precise data, but it is probable, for the reasons just expressed, that the CoVID-19 infection will spread all over the world and last at least another 2-3 months.
For the data we have, we can also say that Coronavirus mortality is strongly influenced by the age of the affected person, by his pre-existing health conditions and above all by the help that the patient obtains from the National Health System.
The health conditions of the affected country are very important, because 20% of infected people in China have needed hospital treatment for weeks (6), however most of the beds were already occupied by people who were hospitalized for other diseases. In addition, CoVID-19 seriously ill patients die in a higher percentage if there are no beds available in the ICU wards. Therefore, the most important thing is firstly to aggressively contain the spread of the virus to keep the number of seriously ill patients low and secondly to increase the number of beds (including medical supplies and medical and nursing staff) up to when there won’t be enough for the seriously ill (that’s exactly what our government has been trying to do in the last few days).
But what are the characteristics of the deaths caused by the new Coronavirus?
They are essentially elderly (about 84%) and immunosuppressed … and among these the mortality is obviously much higher than 2.3%, but the same also happens for the common flu.
People most at risk
Viruses can enter and multiply in all people who come into contact with them, however causing different effects. As for Coronavirus, the data available so far allow us to say that this infection can cause (2, 3, 7):
- An asymptomatic infection or with symptoms that do not attract the attention of the person: it is difficult to say how many people can be affected because, as with all viral infections, some subjects are asymptomatic or have disorders similar to those of a common cold or a mild and transient pharyngitis. These people are usually not elderly, have a very robust immune system and generally do not even undergo medical checks because they don’t think they have the infection. However, it must be said that, according to the WHO expert document (6), the vast majority of people infected sooner or later develop symptoms. Cases of people in whom the virus has been detected and who have no symptoms at the time are rare and it seems that most of them get sick in the following days.
- A mild infection: affects about 80% of infected people (with positive swab); these people (generally elderly and / or carriers of some pre-existing chronic pathology) are those who have a not very strong immune system, like that of the previous group, but still strong enough to confine the pathology which therefore will be expressed only with the symptoms of a simple flu syndrome.
- A serious infection: affects 14-15% of infected people; these people are the immunologically weak ones who therefore develop symptoms so important that they require hospitalization in conditions of isolation.
- A very critical or deadly infection: affects about 3-5% of infected people; these people are those so weak that they are unable to manage the disease, usually they experience bilateral basal pneumonia (75-79% of these cases) which is characterized by intense dyspnea with a respiratory rate of about 30 acts / minute, blood saturation 92-93% oxygen and lung infiltrates in more than 50% of the pulmonary field within 24-48 hours (the most affected lobe appears to be the lower right lobe) (8); if they do not receive assisted breathing, they risk succumbing to respiratory failure, septic shock and multi-organ failure in a highly variable and subjective time (9). According to data published by a study (10). Among critically ill subjects, only 11% did not experience fever until 2-8 days after the onset of symptoms, the average time interval from onset of symptoms to radiological confirmation of pneumonia was 3-7 days and that from the onset of symptoms to admission to the ICU was 7.0-12.5 days.
The real and real risk of CoVID-19 infection depends on the conditions of the immune system:
1- Potentially, we can all be at risk, because each of us could be “temporarily” in a “temporary” condition of risk due to some imbalance and weakening of the immune system. Among the main causes of imbalance, I remember essentially:
- very intense and prolonged psycho-physical stress, especially those that leave agitation, anger, fear;
- heavily impaired nutrition (“junk food”);
- quantitatively impaired nutrition (too scarce or excessive);
- nutritionally impaired nutrition (i.e. poor in essential nutrients that our body absolutely needs for its vital processes: oxygen, water, essential amino acids, essential fatty acids, vitamins, minerals);
- excessive scarcity of drinks, especially if it occurs for a long time;
- excessive sedentary lifestyle;
- excessive reduction of night’s rest, especially if it occurs for a long time;
- chronic exogenous intoxication (excessive consumption of drugs, alcohol, coffee, smoking, drugs).
If the immune-balancing conditions were not severe, intense and too prolonged and if the subject is robust and not elderly enough, in 80% of cases the CoDIV-19 infection will manifest itself slightly and therefore it will be sufficient to remain in isolation / quarantine.
2- 14-15% of people infected, however, due to pre-existing chronic pathologies aggravated by the aforementioned conditions, may find themselves in an immunologically weak situation that they develop a serious pathology that requires prompt hospitalization in conditions of isolation. Indeed, Coronavirus infection is generally aggravated by the presence of some factors among which I mainly remember:
- serious chronic immune pathologies: immunodeficiencies or immune imbalances of various types such as those expressed with recurrent infections, HIV infections, etc .;
- severe chronic respiratory diseases: bronchial asthma, chronic bronchitis, bronchiectasis, respiratory infections, respiratory failure, etc.;
- serious chronic cardiovascular pathologies: advanced ischemic coronary artery disease, atrial fibrillation, dilated myocardiopathy, heart failure, etc.;
- severe chronic metabolic pathologies: decompensated diabetes mellitus, chronic pancreatitis, intestinal malabsorption, severe obesity, excessive thinness, etc.;
- severe chronic kidney diseases: decompensated renal failure, etc.;
- severe chronic neurological diseases, especially those associated with myopathy with respiratory failure, etc.;
- advanced oncological pathologies, with involvement of vital organs and centres, etc.;
- acute or chronic immunosuppressive treatments (corticosteroids, non-steroidal immunosuppressants, cancer chemotherapy, major surgical procedures under general anaesthesia, etc.).
3- About 3-5% of infected people, due to their precarious immune conditions, can enter a very critical state and a part of these people may even face death from multi-organ failure despite the powerful therapeutic aids today available in Intensive Care.
In this regard, I ask: why are not investigated the reasons why one person dies of Coronavirus and another one gets over the infection?
These are the questions that we, doctors, should answer, because if we could understand why one gets seriously ill or dies and why one heals, one could really set up an effective preventive medicine.