What have we learnt from SARS-COV-2 pandemic? Part I

The unforeseen challenges caused by the COVID-19 pandemic have had a significant impact on people around the world.

What is the impact of the COVID-19 pandemic?

At the time of writing, there are over 3,500,000 confirmed cases of COVID-19 worldwide. According to official reports, the largest confirmed cases are in the United States, Italy, Spain and the United Kingdom. However, even countries where the new coronavirus has hit with less aggression are still under considerable strain. Up to 213 countries and territories have registered cases of COVID-19, and the whole world is shaken by uncertainty and questions:

How long will the pandemic last? What will people's lives look like once the pandemic is over?

At this time, many countries have taken steps – some of them strict – to slow the spread of SARS-CoV-2, the virus that causes COVID-19.

What do we know at the moment?

There were reports who said that a new form of coronavirus had begun to spread among the population of Wuhan, a major city in the China, Hubei province. 

Since then, the virus has spread to other countries, both inside and outside Asia, which has led the World Health Organization (WHO) to declare this phenomenon a pandemic. To date, the new coronavirus – now called Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) – has been responsible for millions of infections globally, causing a large number of deaths.

What do we really know about this virus?

SARS-CoV-2 is a coronavirus that causes COVID-19 disease. Coronaviruses are a family of viruses that target and affect the digestive and respiratory systems of animals. Depending on their specific characteristics, there are four main ranks or genera of coronavirus: alpha, beta, delta and gamma. 

Most of these only affect animals, but some can also pass to humans. Those that are transmitted to humans belong to only two of these genres: alpha and beta. Only two coronaviruses have previously caused global outbreaks. The first of these was the SARS coronavirus – responsible for Severe Acute Respiratory Syndrome (SARS) – which began to spread in 2002, also in China. The outbreak of the SARS virus primarily affected the populations of mainland China and Hong Kong and disappeared in 2003. The other was the MERS coronavirus – responsible for Middle East respiratory syndrome (MERS) – which appeared in Saudi Arabia in 2012.

Where did the virus come from? 

In the case of the new coronavirus, initial reports from China have linked the outbreak to a seafood market in downtown Wuhan. However, subsequent assessments have suggested that this market is not likely to be the only source of the coronavirus outbreak, as some people with the virus do not frequent it. Specialists have not yet been able to determine the true source of the virus or even confirm whether there was a single original tank.

How is the virus transmitted?

In Wuhan, at the beginning of the outbreak, some people became ill from exposure to a source, most likely an animal, carrying the disease, which they probably consumed as food without heat processing. This was followed by transmission between humans. As with other coronaviruses, transmission occurs through the respiratory tract, which means that the virus is concentrated in the airways (nose and lungs) and can pass to another person through the particles in the nose or the mouth.

What are its symptoms?

According to the Centers for Disease Control and Prevention (CDC), the main symptoms of COVID-19 are fever, cough and difficulty breathing. Current information suggests that the virus may cause flu-like symptoms as well as severe symptoms such as pneumonia, respiratory failure and, in some cases, death.

How can we prevent infection?

WHO’s official prevention guidelines suggest that, in order to avoid the spread of coronavirus, people should apply the same good personal hygiene practices that can protect them from any other virus. At the same time, it is recommended to maintain a distance of 2 meters from other people. 

Are there any treatments?

There are currently no specialized treatments for COVID-19. When doctors detect a SARS-CoV-2 infection, they seek to treat the symptoms as they occur. As Dr. Van Kerkhove, a renowned epidemiologist, explained: “Because this is a new virus, we do not have specific treatments for that virus. But because we know this virus causes respiratory diseases, these symptoms are treated. Antibiotics will not work against a virus, „she added.

What steps are researchers taking?

Clinical trials are underway to find a treatment and a vaccine against the SARS-CoV-2 coronavirus. Scientists are currently researching the drug Remdesivir against SARS-CoV-2. This is an intravenous drug with broad antiviral abilities. Research has shown potential against SARS-CoV-2 and other coronaviruses. He is also researching hydroxychloroquine and chloroquine, which are prescription drugs for treating malaria and inflammatory conditions. 

Other drugs, including antiretroviral drugs for treating HIV, are also being investigated.SARS-CoV-2: how the immune system defeats the virusAlthough some people who become infected with SARS-CoV-2 have severe symptoms, others can recover after a fairly short period of time. 

A new study shows how another healthy person’s immune system is able to fight the virus in a few days. In a new study in the journal Nature Medicine, researchers at the University of Melbourne and doctors at the Peter Doherty Institute have highlighted how the human immune system develops its response to the new coronavirus. The scientists were able to conduct a case study using information about one of the first patients in the hospital, infected with SARS-CoV-2. This was a 47-year-old woman who had traveled to Wuhan. The patient experienced mild to moderate symptoms of the infection when seeking care. Scientists later expressed interest in finding out how the immune system of an otherwise healthy adult is able to react to an infection with the new virus. 

We have shown that although COVID-19 is caused by a new virus in an otherwise healthy person, a robust immune response to different cell types has been associated with clinical recovery, similar to what we see in the flu,” says co- the author of the study. Prof. Katherine Kedzierska. „This is an incredible step forward in understanding what determines recovery after COVID-19″

People can use our methods to understand immune responses in cohorts larger than COVID-19 and also to understand what is missing from those who have fatal outcomes,” she adds.

An influx of key immune cells

The patient requested specialized care 4 days after the onset of symptoms of viral infection. These symptoms included lethargy, sore throat, dry cough, chest pain, shortness of breath and fever. They were able to leave the hospital and self-isolate 11 days after the onset of symptoms and were asymptomatic until day 13. 

In their study, researchers analyzed blood samples that health professionals collected from the patient with four different occasions: on days 7, 8, 9 and 20 after the onset of symptoms.

„We analyzed this patient’s immune response, using the knowledge we have built over several years to analyze immune responses in hospitalized patients with the flu,” said study co-author Dr. Oanh Nguyen.

The researchers found that on days 7–9 after the onset of symptoms, there was an increase in immunoglobulin G – the most common type of antibody – that rushes to fight the virus. There was also an increase in immunoglobulin M.

This increase in immunoglobulins persisted until day 20 after the onset of symptoms, according to the analysis. On days 7–9 after the onset of symptoms, a large number of helper T cells, NK cells, and B cells — all crucial immune cells — were also active in the patient’s blood samples.

This suggested that the patient’s body was using several „weapons” effectively against the new virus. „Three days after the patient was hospitalized, I saw large populations of several immune cells, which are often a sign of recovery during seasonal flu infection, so I predicted that the patient would recover in 3 days, which was happened, ”notes Dr. Nguyen.

Already established at a number of Melbourne hospitals, we now intend to expand it as a national study,” she added. 

Source: Medical News Today

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