The announcement of the first case confirmed by COVID-19 in Argentina more than a year and a half ago changed the day to day and everyone’s life forever. The concepts of “SARS-CoV-2 virus”, disease by “the new coronavirus” and “pandemic” began to resonate strongly in society and generate fear of the unknown. Today, we can say that we have key information: how it is transmitted, who are the most vulnerable and how we can minimize the risk of being exposed to contagion and becoming seriously ill from coronavirus.
Although there is still much to learn, much of the fundamentals is already known. Despite the misgivings of part of the population by supposed changes of criteria in the measurements, these have really been the reflection of the unprecedented advance of science. On this note, the top five scientific certainties scrapped down in record time thanks to the tireless work of researchers around the world.
1 – The virus is in the air and the greatest danger is indoors without ventilation
“At the beginning, we talked a lot about the importance of hand washing and the presence of the virus on surfaces. Now, we know that the main mode of contagion is aerosols, “said Dr. Lautaro de Vedia, infectologist (MN 70640), former president and current member of the Argentine Society of Infectious Diseases (SADI).
For Fernando Valdivia, veterinarian, consultant in Epidemiology, Public Health and comparative medicine, “the virus is in the air because, like all respiratory viruses, its route of transmission is through fluids and exudates from the mouth and nose . This implies that its transmission does not depend on the virus, but on the dynamics of the air. It is a biophysical question rather than a biological one ”.
“What does this mean? That the transmission of a respiratory virus is impossible to contain: SARS-COV 2 measures between 50 and 200 nanometers and the microdroplets of a sneeze or cough (aerosol) measure between 1 and 100 microns. These microdroplets (containing the viruses) are suspended in the air (like the water droplets in clouds) and are carried by the wind. So, if the virus outside the human body survives about 10 hours and a 10 km / hour wind blows, the virus in that microdroplet can travel about 100 km and still be capable of infecting “, explained the expert before the consultation of Infobae.
He continued: “This is a widely known phenomenon. When we manage epidemics such as foot-and-mouth disease, we find cases in which the virus traveled by air and infect animals more than 200 km away. This explains why both the original virus and the strains and variants that followed have reached all corners of the world regardless of the efforts that were made to contain it ”.
2 – Chinstraps serve to stop contagion
Chinstraps or masks began to be used since March last year in the West as a protective measure against the coronavirus. Research published in The New England Journal of Medicine revealed that the mask is one of the pillars of controlling the COVID-19 pandemic, and that universal facial masking can help reduce the severity of the disease and ensure that a higher proportion of new infections are asymptomatic.
In dialogue with Infobae, Dr. Amós José García Rojas, president of the Spanish Vaccination Association, asserted: “The knowledge and scientific evidence generated in relation to the COVID-19 pandemic showed that SARS-CoV-2 is transmitted by aerosol sprays. That is why we must take special precaution in closed places. Outdoors, contagion is more difficult but if distance is not respected it is also possible. From this perspective, the use of masks becomes a key element in the prevention of infection. Masks outdoors if the physical distance cannot be respected and masks indoors always ”.
And in this, Dr. Pablo Bonvehí, infectious disease physician (MN: 62.648), head of the Infectology and Infection Control Section of the CEMIC, agrees. “From the simplest to the most effective chinstraps, all have been shown to reduce the possibility of transmission not only from the person who has the virus, but also from the person who does not have it and uses the mask. Some liken it to the effectiveness of a dose of the vaccine. In fact, in countries where chinstrap measures have been relaxed and with the appearance of new variants, infections increased ”, the specialist stressed.
However, the effectiveness of the masks is still up for debate. Compared to N95 / FFP2 respirators that have very low particulate penetration rates (around 5%), surgical masks and the like exhibit higher and more variable penetration rates (around 30-70%). “This type of respiratory virus is highly contagious and, as I said before, impossible to contain. However, this type of virus, being highly contagious, has low lethality, and this fact allows the formulation of specific epidemiological strategies, which should not precisely include the use of the chinstrap ”, remarked Valdivia.
3 – Strict confinement was effective
The 2020 lockdown in practically the whole world was a very drastic measure, but also useful to reduce the transmission of a virus that was much more unknown at that time and circulating uncontrollably. “It was a measure that had a clear impact on the pandemic. Interestingly, it is a classic lifelong public health measure. It was evident: if we confined ourselves, we avoided contacts and, therefore, contagion, ”added García Rojas.
“From an epidemiological point of view, home confinements were very useful. When one is not circulating and is at home, there is less possibility of transmission. The virus needs a human being and his cells to multiply. If humans do not have contact with each other, the virus is not transmitted, ”said Bonvehí.
Even so, for Valdivia, “there is scientific evidence that shows that there is no significant difference in morbidity and mortality rates between countries, regardless of the type of restrictions they have imposed. Countries with very light restrictions, such as the case of Sweden, show similar numbers to those of our country, with the aggravating factor that the confinements entail enormous economic and health liabilities that are difficult to quantify ”.
“Because of the confinements, we will see an increase in the incidence of all diseases for many years, either due to the lack of controls or due to the immunosuppressive effect of living locked up. Our biology was not designed to live shut up, and that comes at a very high cost. It is the first time in the history of medicine that healthy people have been confined, against all the evidence and epidemiological theory that indicates otherwise, ”the expert warned.
4 – Age is the greatest risk factor
Trends in infections and deaths from coronavirus by age have been clear since the beginning of the pandemic: older adults represent a large percentage of cases and the deceased because they belong to a risk factor group. In fact, an investigation carried out last August and published in the journal Nature, determined that for every 1,000 people infected with the coronavirus who are under 50 years old, almost none will die. For people in their fifties and sixties, about five will die, more men than women. Then the risk rises steeply as the years roll on. For every 1,000 people aged 70 and over who are infected, about 116 will die. These are the stark statistics obtained by some of the first detailed studies on the risk of mortality from COVID-19.
One of the characteristics that older adults have is to develop age-related health conditions, for example diabetes, hypertension, chronic lung disease, among others. All of these, although they can occur at any age, are recorded more frequently in the population aged 60 years and over.
“As in all diseases,” Valdivia continued, “age and / or certain conditions of concurrent diseases constitute the main risk factor. This is a biological reality given by the fact that at an older age the immune response capacities for defense decrease. The annual statistics on the prevalence of serious respiratory diseases in adults, including pneumonia, are and will always be higher compared to younger populations ”.
“The evidence has shown that the fundamental risk factor in relation to SARS-CoV-2 is age. Based on the fact that this is the main risk factor, vaccination schedules have been planned, ”added García Rojas.
5 – Vaccines work
“Vaccines save millions of lives every year. Its function is to train and prepare the body’s natural defenses? The immune system? to detect and fight selected viruses and bacteria. If the body is subsequently exposed to these pathogenic germs, it will be ready to destroy them immediately, thus preventing disease, “explained the World Health Organization (WHO) recently.
He added: “Vaccines are a new and essential tool to end COVID-19 and it is very encouraging to see the number of them that are in development and the good results obtained in some cases. Around the world, researchers are working as fast as possible, collaborating and innovating so that we have the tests, treatments and vaccines that together will save lives and end this pandemic. There are at least 7 different vaccines [N d R: son en total 9, pero la OMS no ha aprobado todavía las vacunas chinas de Sinovac y Sinopharm] that countries have started to manage across three platforms, prioritizing vulnerable people in all cases. In addition, there are more than 200 experimental vaccines in development, of which more than 60 are in the clinical phase.
One of the most respected voices in the medical environment and who has been encouraging the global vaccination campaign against SARS-CoV-2 is the renowned American cardiologist and geneticist Eric Topol, editor-in-chief of the health site Medscape, who via Twitter He again stressed that vaccines provide 100% protection against death and hospitalizations due to coronavirus.
“Without a doubt, vaccines work because they generate immunity. And they serve two things; at the individual level, to be better prepared in case of contagion; and at the epidemiological level, because a pandemic of this type is controlled by very high percentages of the population that are immunized (either because they have been in contact with the virus or because they are vaccinated). It is what is known as ‘group immunity’ or ‘herd immunity’ ”, highlighted Valdivia.
And he concluded: “When levels of between 60 and 70% of the immunized population are reached before, the disease will disappear as an epidemiological problem, although it will surely remain with annual recurrence like the rest of the similar viral diseases, such as the flu, also affecting mainly to risk groups ”.
For García Rojas, vaccines are “the great scientific milestone that has allowed us to confront in a powerful way what has undoubtedly been the greatest global health crisis in recent times. They have made it possible for the impact of the virus on vulnerable people to be much less than before their arrival. Thanks to having the vulnerable population protected, at this time the impact on their mortality has decreased considerably ”.
“Vaccines are the only chance we have to get out of this,” concluded De Vedia. / Infobae