The COVID-19 pandemic continues its peak in Latin America and Africa, but the number of cases has dropped dramatically in Europe. A study published in Nature a couple of days ago estimated that confinement and social distancing in time could have prevented 530 million infections worldwide.
As it is a self-limited infection – which does not last more than 1 to 3 weeks – and there is no chronicity, many of the chains of contagion have been aborted with a confinement of only 6 weeks. In many parts of Europe there are hardly any active infections at this point, unlike in March, when outbreaks of COVID-19 were rife. In Spain, in particular, less than 50 new infections are reported daily.
Everything suggests that the staggered recovery of the normal rhythm, with masks, activities in open spaces (favored by the summer weather), avoiding proximity, isolating the symptomatic and keeping their contacts in quarantine, will help prevent a re-outbreak of COVID- 19 at least until next fall-winter.
If a second wave comes, nothing points to it being like the first COVID-19 tsunami in March and April 2020 . The health system is now prepared, with enough doctors and nurses who are no longer sick or quarantined, and equipped with protective equipment. In addition, there are more beds in the emergency room, on the floor and, above all, in the intensive care units. On the other hand, we have learned to better treat the disease. Finally, measures have been put in place to ensure adequate care in geriatric residences, where more than a third of all deaths from COVID-19 occurred. One of the most important lessons from the pandemic is that, in general, we must improve care for the elderly.
Fewer cases and fewer deaths
In the last weeks the numbers of new infected by SARS-CoV-2 have fallen drastically. But more impressive is the reduction in the number of deaths: less than 5 a day. Has the coronavirus gotten less virulent? There is no evidence that mutations have been selected that reduce its pathogenicity, although the adaptation of the coronavirus to the human species makes it foreseeable that this will occur over time and that it will become one more respiratory virus than those that cause winter colds.
The lower COVID-19 fatality in recent weeks could be due to the fact that many of the new infections occur from small inoculums, as opposed to what happened in March, when there was no social distancing. Then we hugged and kissed each other, spent hours together in closed spaces, and no one was isolated with a cough or fever.
After all, we must not forget that there is a direct relationship between the degree of exposure to SARS-CoV-2 (concentration of the virus in the environment and for how long) and the possibilities of contagion and, if it occurs, with the risk of suffering from severe forms of COVID-19, including pneumonia, cardiovascular disorders, and thromboembolic events.
Determinants of severity of COVID-19
Investigation of patients who have developed more severe forms of SARS-CoV-2 infection has identified at least 6 predictors of severity:
- Advanced age. Mortality increases proportionally with age and is greater than 20% in patients over 80 years of age. In Spain, 75% of the deceased were over 75 years old.
- Comorbidities. More than 80% of the deceased suffered from chronic diseases, such as diabetes, heart attacks, cirrhosis, cancer, obesity, etc.
- Male gender . Two of every 3 deceased were men.
- Genetics. People with blood group A or with mutated genes for innate immunity develop severe forms of COVID-19. The same is true for people with Down syndrome.
- Cross immunity with other coronaviruses . Catarrhal infections by other endemic coronaviruses during the winter partially protect against the new coronavirus.
- Viral inoculum. People in close and continuous contact with those infected had a higher risk of becoming infected and suffering from more serious forms. Although it is somewhat intuitive and well established for the flu, we hardly have data for COVID-19. This information is important, because outdoor activities reduce both the risk of contagion and that of suffering from severe forms of COVID-19.
Prevent severe forms in future outbreaks of COVID-19
Metaphorically we can say that the tragic March storm will not happen again, but there will be drizzle for months and until a vaccine is developed.
In my opinion, to prevent damage in future outbreaks of COVID-19 you have to work on at least 4 fronts :
- Improve the health system;
- Protect the most vulnerable, especially the elderly;
- Universalize diagnostic tests so that they can be done all and as many times as necessary. Having rapid tests on saliva for sale in pharmacies will help.
- Consolidate good habits of social distancing, including masks for closed places and crowds.
Facilitating and promoting that the maximum number of people take antibody tests allows us to know how many have been exposed and are protected, even if only partially and temporarily. Thus, in Madrid we know that about 15% of the population has been infected and, even if only for 1-2 years, they are protected from reinfection, as a study in macaques has recently shown.
Vicente Soriano, Faculty of Health Sciences & Medical Center, UNIR – International University of La Rioja
This article was originally published on The Conversation. Read the original.
