Coronaviruses: SARS-CoV-2 (COVID-19)

Today, the term “coronavirus” in the majority of the world’s population causes, if not panic, then at least anxiety. In the memory of the people inhabiting the Earth today, there were various cataclysms, natural disasters and epidemics, but humanity faced a pandemic of this magnitude for the first time.

However, coronaviruses, which most of us first heard about only when the COVID-2019 epidemic began, are nothing new for virologists. Their characteristics, description and features have long been known to specialists. True, this particular strain, which caused the 2020 pandemic, has certain differences from its “relatives”, which makes it very difficult to deal with it.

More than one article has already been written about the new coronavirus, revealing the essence of the disease and possible options for its occurrence. But also on the network you can find a lot of information that is far from the truth. In this article, we took into account only scientific facts and collected the most reliable information about coronaviruses and COVID-2019. Let’s figure it out together, is the new virus as terrible as they say about it, where did it come from and what do you need to know about it?

Family of coronaviruses and their classification

The causative agent of COVID-2019 is a specific class of viruses. Viruses are infectious agents (parasites) that, penetrating into the cells of the host organism (human, animal, plant), cause disease. Depending on the structure, different types of viruses are distinguished: RNA-containing and DNA-containing, which in turn cause various types of diseases. It is viruses that can cause respiratory, many gastrointestinal, neurological and other infectious processes. Coronaviruses, which will be discussed next, belong to the class of RNA viruses that cause respiratory diseases. ^[1].

Coronaviruses (Coronaviridae) is a fairly large list of viruses that can cause an infectious process after entering sensitive animal and human cells, with a wide range of respiratory syndromes of varying severity. According to antigenic and genetic properties, 3 main groups of coronaviruses are distinguished. Groups 1 and 2 include viruses pathogenic for mammals, group 3 – pathogenic for birds. Viruses pathogenic for humans are presented both in the first and in the second group.

They got their name because of the characteristic appearance of the virus particle under electron microscopy – protein spikes frame the virus particle like teeth in the crown. With these surface spikes, which are the surface receptor protein S, the coronavirus binds to receptors on the cell membrane. They capture the “imposters” with the “crown”, after which the virus easily penetrates into the cell. The life cycle of all coronaviruses is approximately the same. When comparing SARS-CoV-2 (the causative agent of COVID-2019) and SARS-CoV-1, it was shown that the former is characterized by a high affinity for receptors, as a result of which infection occurs much faster. This difference makes it extremely dangerous.

Penetrating into the cell, the virus begins to assemble its proteins on the ribosome, which cannot determine whether it is virus RNA or proteins useful for the cell. The uniqueness of coronaviruses lies in the fact that their genome is represented by a linear non-segmented single-stranded RNA. The genome size of coronaviruses is the largest among all RNA-containing viruses. Because of this, it is much more difficult to deal with them than with simpler agents. ^{[2] [3] [4]}.

The modern classification of viruses is quite complex. If we talk separately about the family Coronaviridae, then it, along with Arteriviridae and Roniviridae, is included in the order Nidovirales (viruses that contain single-stranded RNA). As for the varieties of coronaviruses, at least 2020 species were known to scientists as of January 40 ^[3]. Most of them were first discovered in the 1930s in poultry. In animals, they cause respiratory, neurological, hepatic and gastrointestinal diseases. For the first time, human coronaviruses were isolated by D. Tyrrel and M / Bino in 1965 from a patient with acute rhinitis ^[5].

Only 7 of the currently known coronaviruses infect humans. And the most common among them are: HCoV-229E, -OC43, -NL63 and -HKU1. They usually affect the upper respiratory tract, causing mild to moderate illness. ^[6]. In addition, scientific evidence shows that most people have specific antibodies that develop resistance to the most common coronaviruses. ^[7].

The family Coronaviridae is divided into 2 subfamilies:

• Coronavirinae;
• Torvirinae.

Of particular interest to virologists is the Coronavirinae family, which includes 4 genera of viruses:

• Alpha-;
• Beta-;
• Gamma-;
• Delta coronaviruses

The genus Betacoronavirus is considered the most dangerous to humans. It contains 4 subgenera:

• A (includes betacoronavirus 1 – BetaCoV 1, human coronavirus – HCoV HKU1, murine coronavirus – MCoV, rabbit coronavirus – RbCoV HKU14);
• B (SARS-CoV);
• C (MERS-CoV, bat coronavirus – Pi-BatCoV HKU5, club-footed leather – Ty-BatCoV HKU4);
• D (night bat coronavirus – Ro-BatCoV HKU9).

Torovirinae includes 2 genera of viruses:

• Torovirus;
• Bafinivirus.

Most known coronaviruses are carried by mammals.

Table “Structure of the family of coronaviruses”

Today, three strains of Coronaviridae are considered the most dangerous to humans:

• SARS-CoV-1 (at the end of 2002 caused an epidemic of severe acute respiratory syndrome, SARS – a virus;
• MERS-CoV (in 2012 it caused a surge in a severe respiratory infection called the Middle East Respiratory Syndrome (MERS), respectively, a new pathogen isolated from patients was called MERS – coronavirus);
• SARS-CoV-2 (caused COVID-2019 in late 19) ^[8].

Until 2002, epidemiology defined coronaviruses as relatively safe for humans – which do not cause serious illness, and if deaths due to infection do occur, it is extremely rare. But in 2002, humanity learned about the existence of SARS-CoV-1, the causative agent of SARS. This virus is a member of the genus Betacoronavirus, and its main carriers are bats, camels and Himalayan civet (viverras). During the period of the epidemic, more than 8000 cases of SARS-CoV-1 infection were recorded, including 774 deaths. But since 2004, not a single case of SARS caused by this virus has been recorded. ^[6].

MERS coronavirus (MERS-CoV), also from the genus Betacoronavirus, was discovered by virologists in 2012. Its natural source is camels. Most cases of infection (82%) were recorded in Saudi Arabia. Since 2012, the infection has affected about 2,5 thousand people. To date, the virus is still circulating around the world, causing new cases of the disease. ^[6].

The new coronavirus SARS-CoV-2, which provoked the 2019-2020 pandemic, like the two previous ones, is a representative of Beta-CoV B. Experts suggest that this is a recombinant (hybrid) virus, which was based on two types of coronavirus: bats and another, still unknown in origin. The genetic causative agent of COVID-2019 is at least 70% similar to SARS-CoV-1 ^[6].

COVID-19 disease

In recent months, the abbreviation COVID-19 has been heard by many, but not everyone knows why the new disease is called that way. In fact, the decoding of this combination is the abbreviated name of the disease in English. COVID-19 is “Corona Virus Disease 2019”, which means “coronavirus disease”, which was discovered in 2019.

The first cases of the disease occurred in December 2019 in China (Wuhan, Hubei Province). For a long time, researchers could not find the so-called “patient zero”, that is, the patient who was the first in the world to become infected with a new coronavirus and transmitted the infection to other people. According to one of the latest versions, “patient zero” was a saleswoman of live shrimp named Wei. She traded at the seafood market in Wuhan. Woman developed a fever on December 11, the first known confirmed case on the market ^[9]. Doctors were faced with a completely new disease that they knew nothing about.

The virus that causes COVID-19, despite a certain similarity to SARS-CoV-1, has unique features that are unique to it. In particular, the COVID-19 pathogen is very easily transmitted, so it is important to strictly follow all precautions to avoid infection.

Scientists around the world are studying the nature of the SARS-CoV-2 virus, but there is still no consensus on how it appeared. An analysis of the SARS-CoV-2 genome showed that, most likely, it is some kind of mutation of two animal coronaviruses. But in the body of which living creature the transformation took place is not yet clear to scientists. It is only known that cave bats carry some types of betacoronaviruses, and civets can serve as an intermediate “reservoir” for the virus. But at the same time, many experts are sure that human infection from a bat is impossible. According to another version, pangolins (lizards) could serve as a reservoir for the new virus, from which a person could become infected. Scientists have found in the organisms of these animals a virus whose genome is 85-92% consistent with SARS-CoV-2. But research continues ^[10].

While scientists still have much to learn about the origin of the virus, its atomic structure is already known. Scientists from the University of Texas calculated that the external structure of SARS-CoV-2 consists of about 200 million atoms. As it turned out, the “thorns” with which the virus enters the cell occupy only a small part of its shell. Scientists say this knowledge could be useful for developing a cure for the new coronavirus ^[11].

However, despite the fact that the survivability of SARS-CoV-1 and SARS-CoV-2 is approximately identical, the latter infects more people than its predecessor. Experts explain this phenomenon by the fact that infected persons may not feel any signs of the disease for a longer time, but at the same time be carriers of the infection.

How the virus is transmitted

After the first case of infection (from animals) occurred, the infected person became the main source of infection. That is, at this stage, the main route of infection is from person to person.

Experts define the following ways of transmission of SARS-CoV-2:

• airborne;
• contact.

The main factors of infection transmission are called air, household items, products.

There was information about the possible transmission of infection by alimentary and sexual routes.

According to the latest data from virologists, SARS-CoV-2 is not able to circulate in the air and “travel” long distances on its own. That is, the main source of infection is droplets that enter the environment from the patient’s respiratory tract.

Is it possible to get infected through objects

Infection through objects is possible only if they contain a viable coronavirus on their surface. It can only hit objects from the wearer.

If, for example, drops of saliva of an infected person fell on a certain surface, and then a healthy person touched this surface with his hand, and then to his mouth, nose or eyes, we can talk about an extremely high risk of infection.

There is no reliable data on how long SARS-CoV-2 lives on different types of surfaces and how long it remains infectious. But virologists suggest that in this regard, it has about the same characteristics as other coronaviruses. And those, depending on the type of surface, humidity and temperature, can remain viable from several hours to several days.

Scientists at Princeton University determined the lifespan of the virus on different surfaces:

• in aerosols – up to 3 hours;
• on copper – up to 3 hours;
• on cardboard – up to 24 hours;
• on plastic and stainless steel – up to 2-3 hours ^[12].

Research in this direction is ongoing.

Animals as a source of infection

A separate variant of coronaviruses is characterized by its narrow range of natural hosts. Specialists are aware of cases of transmission of coronavirus infections from civets and one-humped camels to humans. Scientists also consider animals to be the primary source of SARS-CoV-2. But which of them caused the 2020 pandemic remains to be seen. Therefore, WHO advises avoiding markets where animals are traded, as well as direct contact with them. To minimize the risk of infection, animal products that have not been thoroughly heat treated should not be consumed, and it is necessary to work with them only in personal protective equipment.

Isolated cases of infection of domestic animals from humans are known. But data on infection of a person from a pet are not available today.

How the virus is transmitted from person to person

As already mentioned, 7 types of coronavirus can be transmitted between people. Among them is SARS-CoV-2. Most often, transmission of the infection occurs by airborne droplets, that is, along with the smallest droplets that are released from the nose or mouth of an infected person during a sneeze or cough. In order for infection to occur, particles with the virus must enter the body. For example, a healthy person can inhale air that contains particles of the patient’s saliva. Therefore, WHO advises during a conversation to keep a safe distance from each other – at least 1-2 m. ^[13]. You can also become infected through kissing, eating food or liquid from the same (not previously disinfected) dishes.

You can become infected not only from a person with obvious signs of the disease. In some individuals, the disease caused by the new coronavirus is asymptomatic, but this does not mean that such a subject is not a source of infection for others. In addition, in the early stages of the disease, the symptoms of COVID-19 are mild, but this does not reduce the risk of infection.

But the fecal-oral route of infection in the case of COVID-19 is considered unlikely, although until researchers have complete information about the features of the new coronavirus, this method of infection is also not completely excluded from the possible ones. Therefore, every time after using the toilet and before eating, you must wash your hands with soap and water.

It is believed that children can shed the virus through the intestines for a long time and thereby maintain an increased epidemiological risk of the spread of infection.

Who is at risk

Children and young people with strong immune systems are considered the least susceptible to the new coronavirus. At the initial stage of the epidemic, doctors assumed that children did not get sick with COVID-19 at all, but then it turned out that this was not the case, and even a case of infection of a newborn was recorded. As a rule, the course of the disease in children occurs in a milder form than in adults, although there have been deaths among this category of patients. In addition, sometimes an infected child may not have symptoms of the disease, but is a carrier.

The main risk groups are the elderly and people suffering from somatic diseases such as arterial hypertension, lung or heart disease, diabetes, cancer. According to statistics, in such individuals, the coronavirus disease is quite difficult and often with serious complications. Statistics (at the end of March 2020) show that the average age of people who died from COVID-19 is 79,4 years. At the same time, more than 71,5% of the dead are men. However, in fact, the main risk factor is not so much the age of the patient as the state of his health, which usually worsens with old age.

As with any other viral illness, COVID-19 is more likely to fall ill with a weakened immune system, including after a recent illness, surgery, people with autoimmune and chronic diseases. According to Chinese researchers, the presence of only 2 chronic diseases increases the likelihood of getting COVID-19 by 2,6 times. Also at risk are smokers who already have lung problems. ^[14].

In addition, according to French researchers, some drugs can complicate the course of coronavirus infection. These are ibuprofen and other non-steroidal anti-inflammatory drugs ^[15], as well as antihypertensives from the group of ACE inhibitors.

But whether a person can get COVID-19 again after recovery depends entirely on the characteristics of his body and the ability to produce a virus – neutralizing antibodies. In some individuals, antibodies are produced after a few days or weeks, while in others this process may not be as active, which theoretically remains at risk of getting sick again.

Mechanisms of development and course of the disease

The etiology (origin, causes), pathogenesis (the mechanism of origin and development) of the disease, as well as the effect of the virus on the human body – this is what researchers are actively studying today.

After the coronavirus enters the human body, the incubation period begins. This is the period of time from infection to the onset of the first clinical symptoms. Initially, it was thought that with COVID-19, it can last from 2 to 14 days. But then it was found that in some individuals the incubation period lasts much longer.

The disease itself in its development goes through 4 stages:

1. The first is viremia. This is the time when the virus enters the bloodstream and spreads throughout the body. Lasts up to 7-9 days. At this stage, the patient’s condition can be difficult to distinguish from the common cold.
2. Second. The destruction of epithelial cells begins. Lasts from 9 to 14 days. The development of viral-bacterial pneumonia begins, viruses inhabit the space of the respiratory tract. If the spread of the infection is not stopped, the risk of death is high.
3. Third. There are complications in the form of acute respiratory distress syndrome (non-cardiogenic pulmonary edema). Patients at this stage can no longer breathe without a ventilator.
4. Fourth. Immunosuppression and autoaggression develops – a state of immunity when its protective properties are inhibited and damage to one’s own cells develops. In addition to the main manifestations of the disease, other organs are also affected. This is the last stage of development of COVID-19 ^[16].

The most common clinical manifestation of the disease is bilateral pneumonia. Approximately 3-4% of those infected develop signs of acute respiratory distress syndrome ^[17].

According to WHO, in about 80% of cases, patients recover successfully and do without specific treatment (most often children and young people with good health). But about one in 5-6 cases is accompanied by severe symptoms and a complication in the form of respiratory failure. ^[13].

Symptoms of COVID-19

As a rule, the first symptoms of the disease appear 2-14 days after infection. Symptoms of COVID-19 vary depending on the severity and stage of the disease, the characteristics of the organism.

Main features:

• fever;
• weakness;
• dry cough;
• uneven breathing ^[18].

Some people also experience the following symptoms:

• coryza;
• nasal congestion;
• pharyngitis;
• diarrhea;
• body pain.

Sometimes the disease is asymptomatic ^[13].

The initial stage of the disease is characterized by typical symptoms of SARS. In more than 90% of patients, body temperature rises at this time. In 80%, a dry cough occurs, sometimes with some sputum. In 55 patients out of 100, shortness of breath develops, which increases by the 6-8th day of illness, and in 44 out of 100, fatigue and myalgia appear. Approximately one in five complains of congestion in the chest. Quite rarely, the first symptoms of a coronavirus infection are diarrhea (3%), hemoptysis (5%), headaches (8%), confusion (9%). Sometimes symptoms appear without fever ^[17]. There are also cases where people in the initial stage of COVID-19 lost the ability to distinguish between smells and tastes. Any of these symptoms is a reason to see a doctor.

At later stages, rapidly progressive respiratory failure and sepsis are diagnosed. Complications are also possible in the form of acute heart and / or kidney failure, infectious-toxic shock, hemorrhagic syndrome, multiple organ failure. ^[17].

The most common complication of pneumonia caused by coronavirus is acute respiratory failure.

Diagnosis for the presence of a virus

COVID-19 diagnostics can detect:

• suspected coronavirus infection;
• probable infection;
• confirmed case.

COVID-19 is suspected if there are clinical manifestations of ARI, pneumonia, or bronchitis in combination with one of the items in the epidemiological history, suggesting that 2 weeks before the onset of symptoms, a person:

• was in the region of distribution of COVID-19;
• had contact with people diagnosed with COVID-19.

They say about probable infection if the epidemiological history is combined with severe pneumonia, sepsis, acute respiratory distress syndrome (ARDS).

If a laboratory test confirms the presence of SARS-CoV-2 RNA in the body, regardless of what symptoms are observed, they speak of a confirmed case of COVID-19 ^[17].

The main type of biomaterial used for diagnosis is a swab from the nose, nasopharynx and / or oropharynx.

In addition to specific laboratory diagnostics for the detection of coronavirus RNA and antibodies to it, other methods are also used, including:

• blood test;
• determination of the level of C-reactive protein in serum;
• pulse oximetry;
• CT or x-ray examination of the lungs;
• ECG.

Diagnostic methods may vary depending on the patient’s condition and the capabilities of the medical institution.

Most medical institutions have special tests at their disposal that can determine the presence of a new coronavirus in the body. The results of such testing can be obtained after 2 days. But scientists around the world are actively working to create more effective test systems. ^[19].

For example, experts at Oxford University have developed a rapid test that can recognize SARS-CoV-2 RNA fragments, and not the presence of antibodies to it (this is the indicator that conventional tests check). Thus, the test determines the presence of the disease at an early stage within 30 minutes ^[20]. In addition, a team of scientists from London, Lancaster and the University of Surrey has developed a rapid test that also detects the presence of virus RNA in the body and can be used at home. ^[21].

Treatment for a virus infection

Therapy for infection with a new coronavirus is aimed at normalizing body temperature, stopping infectious intoxication, preventing or stopping complications, and eliminating catarrhal syndrome.

First aid for symptoms

The appearance of symptoms characteristic of COVID-19 is a signal to immediately place the patient in the infectious diseases department of the hospital and begin treatment. At the initial stage of the disease, antioxidant and detoxification therapy is used. The most important thing at this time is to stop intoxication. Symptomatic treatment is also carried out with the use of antipyretic, anticonvulsant drugs, antispasmodics.

COVID-19 is a progressive disease, so it is important to start adequate treatment as soon as possible. You should immediately consult a doctor if you experience the following symptoms:

• labored breathing;
• feeling of tightness or pain in the chest;
• blueness of the lips or face;
• confusion ^[18].

At the slightest suspicion of COVID-19, you should not self-medicate.

Therapies

Some mistakenly believe that at the first suspicion of a coronavirus infection, it is necessary to take an antibiotic. However, drugs from this group cannot be an effective medicine for viral diseases, since their activity is aimed at combating pathogens of a bacterial nature, but does not act on viruses.

The infectious disease clinic with special boxes is an ideal place to treat patients with SARS-CoV-2, as they need symptomatic and pathogenetic therapy while maintaining the normal functioning of the cardiovascular and respiratory systems.

There is currently no specific treatment for COVID-19, so in most cases, doctors use the same techniques as for SARS caused by SARS-CoV-1 or MERS-CoV. Usually, for these purposes, they resort to combinatorial therapy with the use of ritonavir, ribavirin, lopinavir, interferon.

The combination of ritonavir and lopinavir is used to treat patients with HIV, but studies have shown that it is also able to inhibit the activity of the protease of the coronavirus, after which it dies.

Ribavirin is a broad-spectrum antiviral drug. It has previously been shown to be effective in the treatment of SARS-CoV-1. However, this drug may have severe side effects in the form of anemia and thrombocytopenia.

Interferon is also known as an antiviral, anti-inflammatory and immunomodulatory drug.

In the therapy regimen, these agents can be used in different combinations and dosages. ^[17].

In addition, if there are no contraindications, it is important for patients to consume up to 3-3,5 liters of fluid per day with the obligatory control of diuresis (the amount of urine excreted). With intoxication and discomfort in the abdomen, enterosorbents are prescribed.

Infusion therapy is used for seriously ill patients, but under mandatory strict medical supervision (so as not to aggravate pulmonary edema).

To improve the excretion of sputum, mucoactive drugs are used, and diuretics are prescribed to prevent swelling of the brain and lungs.

If the patient has a broncho-obstructive syndrome, bronchodilator inhalations are made using a combination of agents.

Symptomatic therapy is aimed at stopping fever, treating rhinitis and bronchitis.

In some cases (with complications of the disease), antibiotics may be prescribed to the patient, as well as non-invasive or invasive ventilation of the lungs (in case of progression of respiratory failure).

Only a mild form of coronavirus disease can be treated at home. But only with the permission and under the supervision of a doctor. Self-medication using traditional medicine, the effectiveness of which has not been proven in coronaviruses, is strictly prohibited. Also, doctors do not advise to bring down the temperature if it does not exceed 38-38,5 degrees, since under such conditions the virus in the body dies.

Development of antiviral agents

Today, the world’s best specialists are engaged in the creation of a vaccine against the “corona”. However, there is no specific drug against SARS-CoV-2 yet. Therefore, at this stage, doctors use existing antiviral agents in various combinations. In particular, French researchers were able to achieve a positive result in the treatment of COVID-1 using a combination of azithromycin and hydroxychloroquine. ^[22].

By the way, hydroxychloroquine, along with chloroquine and remdesivir, is most often used by scientists in research aimed at finding an effective remedy against COVID-19. The first two are antimalarial. The third is characterized by pronounced antiviral activity, and it inhibits the replication of the pathogenic agent.

In short, experts continue to study the nature and properties of the new coronavirus in order to create drugs that will help you quickly recover from COVID-19.

Is there a vaccine

Although the search for a vaccine against the disease can take years, there were still high hopes for the timing of a vaccine against COVID-19. And not in vain, on December 31, 2020, an article was published on the WHO.INT website stating that the World Health Organization (WHO) approved the first COVID-19 vaccine on an emergency basis for use around the world ^[23]. This is a joint development of the pharmacological company Pfizer / BioNTech, which has successfully passed all stages of clinical trials and is approved in more than 40 countries around the world.

Research continues on other vaccines: Moderna (mRNA-1273), Gamaleya (Sputnik V), Oxford/AstraZeneca (AZD 1222), CanSino/PetroVax (AD5-NCOV), Bio Farma (Coronavac), Sinopharm (BBIP-CORV). Each of the above vaccines has been approved in at least one country and is currently being used for people who need priority vaccination. ^[26]. In addition, 77 developments are undergoing clinical trials around the world, which include 3 stages ^[27].

The 1st stage involves the initial testing of the vaccine for human safety and determining the effective dosage.

Stage 2 is only available for vaccines that have passed the Stage 1 trial. This phase involves vaccinating hundreds to several thousand volunteers and monitoring them. Or rather, the reaction of the immune system to the vaccine. Very often, the 1st and 2nd phases are combined.

At the 3rd stage, the number of vaccinated volunteers increases to tens of thousands. This phase is considered one of the most dangerous, as people are at greater risk of infection due to the composition of the vaccine itself, which may contain the virus.

If all stages of clinical trials of the vaccine have been successfully completed and its effectiveness has been proven, which is documented, then it can be considered as potentially approved by the competent authorities.

There are 3 classifications of drugs for immunization (vaccines):

• A live vaccine contains the causative agent of the disease. However, pathogens are weakened and unable to harm the human body, at the same time, this is enough for an adequate response of the immune system.
• An inactivated vaccine, in turn, consists of dead disease-causing organisms or their particles.
• Toxoids are preparations that contain toxins of pathogenic bacteria, which are previously specifically processed.
• Molecular vaccine – based on synthesized proteins of pathogenic bacteria, which are obtained in the laboratory using genetic engineering.

Among the approved vaccines, most of them are classified as the result of molecular development, with the exception of Chinese vaccines from Sinopharm and Bio Farma, which are developed from a dead virus.

As for vaccination in the world, at the moment in 48 countries either clinical trials or vaccination of the population with one of the approved drugs are underway. The leading countries in administered doses are China (9 million), USA (9 million), UK (2,68 million), Israel (1,85 million), UAE (1,17 million doses) ^[28]. In total, as of mid-January 2021, over 19 million people around the world have been vaccinated against COVID-28.

preventive measures

Until there is a vaccine, the only way to protect yourself from infection is prevention. It should be understood that specific prevention has not yet been developed to date.

Non-specific precautions for coronaviruses:

• regular hand disinfection (alcohol kills the virus on all surfaces);
• keeping a distance with infected or potentially infected;
• do not touch your nose, mouth or eyes;
• do not visit regions where outbreaks of the virus have been recorded.

And the best protection when in contact with a potentially infected person is a mask.

In addition, in order to prevent the spread of coronavirus, it is important not only to protect yourself from infection, but also to try not to become a distributor of a pathogen yourself. And for this, you should follow the rules of so-called respiratory hygiene. In particular, WHO recommends using either a tissue during sneezing and coughing, or, if it is not available, cover the nose and mouth with the bend of the elbow. The same rules are effective for preventing the spread of any viral diseases, including SARS and influenza. ^{[13] [24]}.

If you have a fever, cough, or trouble breathing, it is important to seek immediate medical attention and minimize contact with other people.

Recombinant interferon alfa is sometimes recommended as a drug prophylaxis. ^[17].

The COVID-19 pandemic and its statistics

The outbreak of COVID-19 began at the end of 2019 in the Chinese city of Wuhan. On December 31, China informed WHO about the spread of pneumonia of an unknown type, and on January 22, 2020, the city was quarantined.

The first case of the disease outside of China was recorded on January 13 in Thailand (Bangkok). It was a woman who had flown in from Wuhan. On January 30, the WHO declared an outbreak of an unknown disease an international emergency, and on March 11, COVID-19 will receive the status of a pandemic.

Since March 13, the center of the pandemic has moved from China to Europe, where for a long time Italy remained the leader in the number of patients. Since March 26, the United States has taken the lead.

Information on the number of infected persons is constantly updated. As of April 6, 2020, over 205 million cases of COVID-1,27 infection have been recorded in 19 countries around the world. At the same time, more than 264 thousand people were successfully cured, and more than 69 thousand died. The highest incidence was recorded in the United States. Mainland China, Italy, Spain, France, Germany, the United States, and Iran have suffered the most from the pandemic.

To prevent the spread of the disease around the world, starting March 17, the European Union and the Schengen area closed their borders for 30 days. Similar measures have been taken in most countries of the world. In addition, many states in Europe and America announced quarantine, due to which educational institutions, many institutions, shopping and entertainment centers were closed. In many cities, residents under pain of imprisonment for the period of quarantine are prohibited from leaving their homes without a good reason. Due to quarantine, many iconic events have been canceled, including the European Football Championship, the Summer Olympic Games, the Cannes Film Festival and the Eurovision Song Contest ^[25]. But despite all the measures taken, the virus is spreading very quickly around the world, and this is its main danger.

COVID-19 has every chance of going down in history as one of the major disasters of the XNUMXst century, claiming tens of thousands of lives across the planet. The pandemic caused the stock market to collapse and gave rise to a new global economic crisis.

Humanity will take a long time to “recover” from the consequences of COVID-19. And as many experts suggest, pandemic survivors will never be the same again. COVID-19 has forced many to reassess their life values ​​and look at the world around them with completely different eyes.

Sources of