A man became infected with the new coronavirus after having the covid-19 disease last April, in what scientists consider to be the first documented case in which reinfection was proven.
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According to a scientific article accepted for publication in the journal Clinical Infectious Diseases, researchers from the department of microbiology at the University of Hong Kong confirmed that the second Sars-CoV-2 infection of this 33-year-old individual was detected through an airport control in Asia after returning from Europe.
To confirm this, the scientists used genomic sequence analysis in which they confirmed that reinfection was the result of a strain other than the initial infection.
According to the study, it is about an information technology worker who did not develop any symptoms in his second infection so it infers that “any subsequent infection could be milder.”
“Our findings suggest that Sars-CoV-2 may persist in humans,” said Kwok-Yung Yuen, one of the researchers, of the paper that is in the process of being published.
What was revealed agrees with the information that was known about the coronaviruses that cause the common cold, in the sense that by continuing to circulate they allow Sars-CoV-2, which is from the same family, to have the same behavior.
“This would happen even if patients have acquired immunity through natural infection or through vaccination.”Yuen added.
It is worth mentioning that although some patients have previously tested positive for the virus weeks after ending symptoms, scientists have not fully understood whether these cases are persistence of remains of the virus or the result of a second infection.
In a statement to the press agencies, researchers from the University of Hong Kong assure that this “It is the first documentation in the world of a patient who recovered from covid-19 and was re-infected with Sars-CoV-2 some time later.”
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Around the world, almost 24 million people have been diagnosed with the new coronavirus, and most of them, according to other research, develop a defense response to the infection. However, it is not yet determined how strong and long-lasting this immunity is.
For now, according to the same researchers, more studies are needed to track more of these types of reinfection cases to determine the quality and durability of the neutralizing antibodies produced by recovered Sars-CoV-2 patients.
Until now it had also been said that recovered patients had a level of defense that decreased after a few months.
An article published in Cell delved into the topic and found that specific memory (defense) T cells against Sars-CoV-2 are likely are definitive for long-term immune protection against this virus.
The study systematically mapped the functional and genetic characteristics of the responses of these T cells stimulated by Sars-CoV-2 in unexposed individuals, relatives of those exposed and in covid-19 positive people in acute and convalescent stages.
According to the findings, these specific cells in the acute phase of the infection showed cytotoxic characteristics (aggressive against the virus) highly activated that were associated with several clinical markers of disease severity. Meanwhile, the cells specific against Sars-CoV-2 in the convalescent stage were polyfunctional (against various agents) and showed genetic characteristics similar to normal cells.
The article highlights that specific cells against Sars-CoV-2 were also detected in exposed relatives, with which it can be concluded that the data collected shows that Sars-CoV-2 provokes memory cell defense responses “Robust, spacious and highly functional, suggesting that natural exposure to infection can prevent recurrent severe covid-19 episodes.”
The Cell article would explain why the second covid-19 attack in the Hong Kong patient was less severe and asymptomatic. However, in the face of these, all researchers agree that More studies are needed to draw conclusions that for now point to a probable immunity against covid-19.