Tuesday, January 19

What scientists know about Covid-19 a year later

A vaccination team in a residence in Ourense.

A vaccination team in a residence in Ourense.
I. Osorio

The year 2020 will go down in history as the year of the pandemic Covid-19. In addition to the enormous health and economic impact, and the very high number of deaths and infections that it leaves behind, the SARS-CoV-2 It has changed the way of life and social practices in much of the world, while generating a significant cultural and emotional impact. Throughout these twelve months, scientists from all over the world have devoted themselves to investigating the coronavirus, as it was showing and now the Carlos III Health Institute collects the knowledge acquired in a report. The long-awaited work of vaccines, the possible treatment findings and the continuation of preventive measures and public health “will make it possible to overcome this pandemic, which is a new warning of the need to gather knowledge and resources to face other similar scientific and health crises that may occur in the future.”


The exact origin of SARS-CoV-2 has not yet been revealedAlthough it is known that transmission to people came from an animal, perhaps directly from a bat or through the infection of an intermediate species as occurs in SARS and Mrs. The first known case was reported on December 31, 2019 in the Chinese city of Wuhan and it is similar to other known corona viruses, but with specific characteristics. The disease it causes is Covid-19.

Biology and mutations

In January 2020, the first SARS-CoV-2 genomes began to be sequenced and in Spain, in March, scientists from the Carlos III National Microbiology Center carried out the complete sequencing of the virus, thanks to respiratory samples from patients from different Spanish geographical areas. . Like all viruses, SARS-CoV-2 has suffered small genetic mutations, something common, although it is known “that it does not mutate excessively”, although given its pandemic spread, close monitoring of its mutations is necessary. An example is the variant registered in the United Kingdom, which is associated with a possible increase in transmission “not yet confirmed”. And it is that “for the moment it has not been determined that the mutations of the virus acquired now have increased its lethality”.

Transmission by secretions, contact and aerosols

Different forms of transmission are recognized and are still being studied: the main one is the secretions of infected people, mainly by airborne transmission, produced by talking, coughing or sneezing, so the use of masks is one of the main methods of containing its dispersion. The infection can also be transmitted by contact with contaminated objects by these secretions, followed by contact with the mucosa of the mouth, nose or eyes, so that hand hygiene is another of the most recommended preventive methods. In recent months the air transmission of the virus, what we know as aerosols, after finding evidence that SARS-CoV-2 particles can remain suspended in the air. Hence, the importance of ventilation in closed spaces.

Symptoms and immune response

The new coronavirus does not cause the same symptoms in all people and, in fact, many do not develop any symptoms, are called asymptomatic, but they can transmit the infection. Those who develop symptoms can present it in a multiple and variable way. Cough, sore throat, fever, anemia (loss of smell), Asia (loss of taste), muscle pain, headache, shortness of breath and diarrhea are some of the most common symptoms. In addition to affecting the respiratory tract, the new coronavirus also has the ability to infect numerous organs and generate a great clinical diversity of manifestations. Most patients are mild or asymptomatic, but in 15-20% of cases the disease worsens and 1% of patients die. Normally the immune system is able to control the virus before it spreads through the body before it reaches the lungs

Corticosteroids and heparin as treatment

There are hardly any specific effective treatments against Covid-19, despite intense research and the range of options that have been studied around the world since the beginning of last year. Corticosteroids are the only drugs that seem to have shown some usefulness, by allowing a reduction in mortality in seriously ill patients, although its efficacy is still under investigation. The anticoagulant heparin is also used to combat clotting problems, while its use remains under investigation. Other alternatives, such as the use of antivirals or Redeliver, used in Ebola, have not yielded positive results, which is why the WHO advises against their use due to lack of evidence. The same is true for hydroxyloquine or the use of plasma from recovered patients to treat acutely infected patients, although several studies are ongoing.

Ongoing vaccination

In the field of vaccines, the scenario is different. The first ones have just been approved, after an unprecedented global effort to develop prototypes and accelerate their completion and in December the vaccination of the groups considered priority began. There are many prototypes in development, in different phases of clinical trials. Ten vaccines have entered or completed phase III trials, the last link in development before commercialization.

More than 1.5 million infections in Spain, which exceeds 50,000 deaths

In Spain, up to the date of publication of this document, more than 1.85 million cases and almost 50,000 people died, according to the cases officially notified to Health by the autonomous communities, which leaves a mortality rate of around 106 deaths per 100,000 inhabitants.

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