Globally, some 24 million people are known to have been infected with Covid-19.
A man caught the coronavirus after recovering from a first bout in April in what scientists said was the first case showing that reinfection can occur in a few months.
The 33-year-old second SARS-CoV-2 infection was detected by screening at the airport upon his return to Hong Kong from Europe this month. Researchers at the University of Hong Kong used genomic sequence analysis to prove he was infected with two different strains. The information technology worker did not develop any symptoms of his second infection, which could indicate that “subsequent infections may be milder,” the researchers said.
“Our results suggest that SARS-CoV-2 may persist in humans,” Kwok-Yung Yuen and colleagues said Monday in an article accepted for publication in the journal Clinical Infectious Diseases. The results also suggest that SARS-CoV-2 is reminiscent of coronaviruses that cause colds and could continue to circulate “even if patients have acquired immunity through natural infection or through vaccination,” they said.
While some patients have tested positive for the virus for many weeks, even after their symptoms have resolved, scientists have not fully understood whether these cases reflect persistent traces of the virus, a re-eruption of an infection. or a new infection.
World premiere
This is “the world‘s first documentation of a patient who recovered from Covid-19, but had another episode of Covid-19 afterward,” the researchers said in a statement sent by email.
It can be difficult to find Covid-19 survivors who have been re-infected with SARS-CoV-2 if they don’t show symptoms, said Corey Smith, head of translational and human immunology at QIMR Berghofer Medical Research Institute in Brisbane.
“Because he showed no symptoms during the second infection, it is likely that although the virus was successful in establishing an infection, his memory immune response likely prevented any symptomatic illness,” Smith said. in an email. “This suggests that natural infection may provide protection against disease, but not reinfection.”
Still infectious?
One problem is that a re-infected person can still spread the SARS-CoV-2 virus to someone who has not been previously exposed, he said.
It is inevitable that re-infections will occur, said Thomas File, president of the Infectious Diseases Society of America and president of infectious diseases at Summa Health, a hospital system in Akron, Ohio. “The question is, how long after the initial infection could this happen?”
Protection against re-infection will vary from person to person and may depend on the individual patient, their immune system, whether the patient has developed symptoms of the first infection and the nature of the second virus to which they have been. exposed, File said in an interview Monday. .
“We know that if you look at the seasonal endemic coronaviruses, the amount of immunity can be as low as four, five or six months up to maybe up to a year or two,” he said. .
Questions remain
Worldwide, some 24 million people are known to have been infected with Covid-19, Maria Van Kerkhove, World Health Organization technical officer on Covid-19, told reporters on Monday. Most patients – even those with mild cases – develop an immune response to the infection, she said.
It is important to document cases like the one described in Hong Kong, “but not to jump to conclusions,” Van Kerkhove said. Studies that can follow a larger number of cases over time are needed to better understand the quality and durability of the neutralizing antibody response of recovered patients to SARS-CoV-2, she said.
(Except for the title, this story was not edited by GalacticGaming staff and is posted from a syndicated feed.)
