QCOSTARICA – How common is reinfection with the SARS-CoV-2 virus, which causes covid-19? That has already been determined for 342 Costa Ricans, who received their second positive test between March 4 and August 22, 2021 (the most recent date for which there is data).
To be viewed as reinfection, these people had their second diagnosis at least 90 days after the first. In the world, there are more than 140,000 suspected cases of reinfection, which are considered underreporting, since not all countries report them.
The Ministry of Health indicated that before March 4 different criteria were used. Last December, 10 suspected cases of reinfection had been reported, of which one was determined to be rather a prolonged covid-19 (that is, the same infection that had not resolved).
48% of these cases are between the ages of 25 and 39; 54% are women and 46% men.
Of these people, only 11% had the full vaccination schedule (two weeks had passed since their second dose), 76% had an incomplete scheme (considered as insufficient protection against the disease), and 13% had no vaccines.
Only one deceased is registered, a 78-year-old man who was not inoculated.
Why can someone get infected more than once?
The fact that a person becomes ill more than twice with covid-19 is something that does not surprise doctors, epidemiologists or specialists in virology. Not all diseases are once in a lifetime (such as measles, in which cases of reinfection are very rare). There are others, such as influenza, in which being infected several times throughout life is common.
There are several factors that can play a role in a person testing positive more than once (regardless of whether or not they have symptoms). On the one hand, there is the immune system and how much response it can mount so that, if faced with the virus, it can counteract it. In those who generate a lesser response or it has worn out, this could be insufficient in case of encountering the pathogen again.
On the other hand, there are individuals who, due to the characteristics of their work, spend more time exposed to a greater amount of viruses, such as health workers in covid areas. In these cases of high exposure, the risk of a second contagion is greater.
As time goes by, reinfections also become more common. Different variants of the virus, becoming more frequent and more diverse, could also make people sick more than once. For example, those who were infected during the first months of 2020 have a greater chance of being exposed and becoming infected with one of the variants that circulate at this time, as they are different.
Vaccinated individuals have a lower risk of infection. However, over time there could be a variant that escapes the action of vaccines and makes them less effective, increasing the chances that someone will test positive again.
“There are countries where much progress is being made with vaccination, but others in which there is not so much progress and have uncontrolled transmission, in these cases mutations could arise and some of these may escape the vaccine,” said the virologist Eugenia Corrales Aguilar.
The scientist points out that the more a virus is transmitted and spread, and the greater its presence in a community, the greater the opportunity to generate new variants and that, eventually, a more transmissible one emerges or that can escape vaccines or evade the antibodies generated in a natural infection.
In this way, it could make someone who already has an immune response sick.
