Is COVID-19 increasingly benign?

By Vicente Soriano, UNIR – International University of La Rioja

The COVID-19 pandemic continues its peak course in Latin America and Africa, but the number of cases has decreased dramatically in Europe. A study published in Nature A couple of days ago, he estimated that confinement and social distancing in time could have prevented 530 million infections worldwide.

As it is a self-limited infection –which lasts no more than 1 to 3 weeks– and there is no chronicity, many of the contagion chains 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 what happened in March, when COVID-19 outbreaks abounded. In Spain, specifically, fewer than 50 new infected people are reported daily.

Everything suggests that the staggered recovery of the normal rhythm, with masks, activities in open spaces (favored by the summer climate), avoiding proximity, isolating the symptomatic and keeping quarantined contacts, will help to avoid a COVID outbreak. 19 at least until next fall-winter.

If a second wave comes, nothing points to it going to be like the first COVID-19 tsunami in March and April 2020. The health system is now ready, with enough doctors and nurses who are no longer sick or quarantined, and equipped with protection material. 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. Lastly, measures have been put in place to ensure adequate care in nursing homes, where more than a third of all deaths from COVID-19 occurred. One of the most important lessons of the pandemic is that, in general, we must improve care for the elderly

Fewer cases and fewer deaths

In recent weeks, the numbers of new people infected with SARS-CoV-2 have fallen dramatically. But more impressive is the reduction in the number of deaths: less than 5 daily. Has the coronavirus become less virulent? There is no evidence that mutations that decrease its pathogenicity have been selected, 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 case fatality rate of COVID-19 in recent weeks could be due to the fact that many of the new infections occur due to small inocula, unlike 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 with a cough or fever was isolated.

After all, it should not be forgotten 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 chances of contagion and, if it occurs, with the risk suffering from severe forms of COVID-19, including pneumonia, cardiovascular disorders, and thromboembolic events.

COVID-19 severity determinants

Research into patients who have developed more severe forms of SARS-CoV-2 infection has identified at least 6 predictors of severity:

1. 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.

2. Comorbidities. More than 80% of the deceased suffered from chronic diseases, such as diabetes, heart attacks, cirrhosis, cancer, obesity, etc.

3. Male sex. Two out of every 3 deceased were men.

4. 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.

5. Cross immunity with other coronaviruses. Catarrhal infections by other endemic coronaviruses during winter partially protect against the new coronavirus.

6. Viral inoculum. People in contact with those infected closely and continuously had a higher risk of being infected and suffering more serious forms. Although it is somewhat intuitive and well established for influenza, we have very little data for COVID-19. This information is important, since outdoor activities reduce both the risk of contagion and the risk of serious forms of COVID-19.

Prevent serious forms in future outbreaks of COVID-19

Metaphorically we can say that the tragic March storm will not happen again, but it will be drizzling for months and until a vaccine is developed.

In my opinion, to prevent damage in future outbreaks of COVID-19 it is necessary to work on at least 4 fronts:

1. Improve the health system;

2. Protect the most vulnerable, especially the elderly;

3. Universalize the diagnostic tests so that they can be tested all and as many times as necessary. Having quick saliva tests available at pharmacies will help.

4 Consolidate good habits of social distancing, including masks for closed and crowded places.

Facilitating and promoting that the maximum number of people get antibody tests allows knowing 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 in The Conversation. Read the original.

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