- It is abbreviated as Covid-19 or COVID-19 to the 2019 coronavirus disease, an infectious disease of the human respiratory system produced by the SARS-CoV-2 virus (acronym in English for Severe Acute Respiratory Syndrome Coronavirus 2) and was first diagnosed in the Chinese city of Wuhan, in Hubei province, in December 2019. The disease is transmitted through person-to-person contact, or through the suspension of infectious particles in the air ( sprays) or when you are in contact with infected surfaces and then bring your hands to your face, nose or mouth.
- Covid-19 is a disease of the human respiratory tract, which produces symptoms very similar to those of the common cold, such as fever, cough, fatigue, headaches, muscle aches and shortness of breath, among others. Loss of smell and taste, and in the most severe cases, pneumonia, acute respiratory distress syndrome, sepsis, and septic shock, as well as clotting and neurological complications, are also common. However, only 3.75% of those infected with Covid-19 suffer from these complications, which can lead to death.
- The transmission of Covid-19 from one person to another occurs, fundamentally, through the so-called “Flügge microdroplets”: tiny particles of saliva that are emitted when speaking, singing or breathing, and in greater quantities, when coughing and sneezing . A person can come into contact with these droplets in three ways: by having direct contact with an infected person, by breathing them directly from the air in poorly ventilated environments, or by coming into contact with the surface of an object containing the droplets and then carrying the droplets. hands to face, nose or mouth. It is believed that the virus can remain active for hours and even days on the surface of certain materials.
- Covid-19 was discovered in China in December 2019, but despite local efforts to contain the disease through a very strict quarantine in different cities in the region, the virus spread internationally and on March 11, 2020 had already been found in around 100 countries. The Covid-19 pandemic was announced by the World Health Organization that same month, and as of this writing (September 2021) it has claimed the lives of some four million people worldwide.
- The virus that produces Covid-19 is a SARS virus from the family of Coronaviridae (or “coronavirus”, since they have a kind of “crown” of proteins in their envelope), between 50 and 200 nm in size, possessing a genome made up of a single strand of RNA. Since its discovery in 2019, numerous other variants have been detected, the result of its high capacity for mutation, several of which are considered “careful” because they could be more aggressive or more contagious.
- To date (September 2021) there are no treatments for Covid-19, so patients can only be helped to overcome the disease by mitigating its symptoms and prolonging life. Although the disease is fatal in a low percentage of cases, it is more complicated in immunosuppressed patients, those affected by cancer or with comorbidities. Fortunately, in December 2020, the first of a varied series of vaccines against the disease was developed, which, although they do not completely prevent infection, do reduce the rate of reproduction of the virus, protecting the vaccinated subject from serious disease. (and therefore, death) in a high percentage of cases. The immune response to the virus, as well as to developed vaccines, however, is currently under investigation.
- Prophylactic or preventive methods in the face of the Covid-19 pandemic include frequent hand washing (or disinfection with alcohol), the use of surgical masks (or cloth masks, to mechanically prevent the dispersion of the droplets to the environment) and social distancing , especially in closed and poorly ventilated environments. There is, however, some room for debate as to which measures may be most effective.
- The symptoms of Covid-19 appear after a variable incubation period, which ranges between 2 and 14 days (5 days on average) after exposure to the virus. The body’s response depends on the immune system of each patient and the range of symptoms of the disease may be different in one case and another, and the disease can even pass without symptoms manifesting. A low percentage of cases may have long-lasting symptoms (called “prolonged Covid” or “Long Covid”) Over weeks or months after you have recovered from the infection.
- There are a significant number of vaccines to prevent severe cases of Covid-19. About 10 of them have already been approved for emergency use by different international health authorities, while another 70 are in different phases of investigation and testing. The effectiveness of these vaccines varies depending on each one, but ranges between 50% and 95% effectiveness. It is estimated that in February 2021, about 101.3 million doses of some vaccine against Covid-19 had been supplied in the world, the vast majority in citizens of developed countries.
- It is still unknown how long exactly the immunity provided by contagion with Covid-19, as well as that provided by vaccines, lasts. There are studies that suggest active protection for several months, with a downward trend over time. Others are more optimistic, but booster doses are likely to be required to update immune defenses against the emergence of new virus variants.
References:
- “COVID-19” in Wikipedia.
- “Sars-CoV-2” in Wikipedia.
- “Outbreak of coronavirus disease (COVID-19)” at the United Nations.
- “Covid-19 Information Center” at Unicef.
- “COVID-19” in the Centers for Disease Control and Prevention (USA).
- “Covid-19 (coronavirus): Long-term effects” at Mayo Clinic (USA).