- Reports of people catching the novel coronavirus a second time are starting to spread, months after the start of the pandemic.
- A Belgian woman would have had a second mild case, three months after her first illness.
- And an elderly person in the Netherlands with a weakened immune system also caught the coronavirus twice, a leading Dutch researcher reported.
- On Monday, scientists confirmed the first case of coronavirus re-infection: a healthy 33-year-old man from Hong Kong who had traveled to and returned from Spain.
- Experts say these results are not cause for concern: they show that our immune system is putting up adequate defense against this virus – a defense that can help fend off the worst effects of the disease a second time around.
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Just hours after the world’s first confirmed case of coronavirus re-infection was documented in Hong Kong on Monday, researchers reported that a woman in Belgium caught the virus a second time. Likewise, the Dutch virus experts, who announced an elderly person in the Netherlands as a third confirmed reinfection of COVID-19, the disease caused by the coronavirus.
Experts used genetic testing, in which they compare the versions of the virus present in the first and second infections, to confirm that these re-infections were separate second cases, and not just lingering effects of the population’s first infections.
But just because a few re-infections of COVID-19 have started to appear among the more than 23.69 million documented coronavirus cases worldwide that an initial coronavirus infection does nothing to protect people from future diseases, or that a vaccine will not help stamp this pandemic.
“I don’t want people to be afraid,” Maria van Kerkhove, World Health Organization technical officer for COVID-19, said on Monday when asked about the reinfection case in Hong Kong. “We need to make sure people understand that when they are infected, even when they have a mild infection, they develop an immune response.
New cases of reinfection in Belgium and the Netherlands
The case of reinfection in the Netherlands, diagnosed in an elderly person with a weakened immune system, was confirmed on Tuesday to Business Insider by Erasmus MC, where virologist Marion Koopmans works. (His data on the case have yet to be made public and Erasmus cited Dutch privacy laws when asked for details.)
“Just because you have accumulated antibodies does not mean that you are immune,” said Koopmans, in an interview on the case of reinfection with the Dutch public broadcaster NOS.
But even if a person does not develop full immunity to a virus and is re-infected, the body seems to remember their previous illnesses. In addition to antibodies, T cells and other components of a person’s immune system all work together to better fight an active infection the second time around.
This appears to be what happened in Belgium, where a woman in her 50s who already had the coronavirus in March was reportedly diagnosed a second time in June.
Belgian virologist Marc Van Ranst has yet to release the data behind his claim either, but said the woman developed very few antibodies after her first infection, and speculated that it may have been the reason she was likely to be re-infected (although her second case was mild).
“We would have preferred the time between two infections to be longer,” Van Ranst told Belgian public broadcaster VRT News. “The antibodies from the first time are not enough to prevent the second infection. ”
He said more of these seemingly rare cases of reinfection would likely continue to appear in the coming months, as people’s immunity to coronavirus (from their previous infections) wanes.
“Maybe there will be others who will have it a second time after 6 or 9 months,” he said.
Researchers reported another case of reinfection in Hong Kong on Monday
The two European reinfection cases bring the official number of coronavirus reinfection cases to three, out of tens of millions.
Previous reports of 260 re-infections in South Korea in April were found to be persistent cases of the same infection. Another potential case of reinfection was reported in the United States in June and 3 more were reported in July in France. But these cases were not considered confirmed re-infections because less time elapsed between positive tests and scientists did not perform a genetic sequence of the viruses.
Researchers at the University of Hong Kong announced Monday that “the world’s first documentation of a patient who recovered from COVID-19 but had another episode of COVID-19 afterwards” is in appear in the peer-reviewed journal Clinical Infectious Diseases.
An apparently healthy 33-year-old man who had been ill in March has been diagnosed with the novel coronavirus a second time after returning to Hong Kong from Spain earlier this month.
While he had a fever, cough, and headache during his first illness with COVID-19, the man showed no symptoms during his second infection.
Why reinfection cases are not unexpected or a reason to panic
Many epidemiologists have anticipated that such coronavirus re-infections could be possible.
“You can be infected multiple times once your immunity wanes,” Florian Krammer, vaccine specialist and virus expert at the Icahn School of Medicine at Mount Sinai in New York City, told Business Insider, when asked about immunity. to coronaviruses.
These three cases are therefore not a reason to panic. Instead, they show how previous infections can provide people with decent protection against another coronavirus disease.
“That someone shows up with reinfection doesn’t make me nervous,” Koopmans told Reuters. “We have to see if this happens often. ”
Indeed, Krammer predicted (just as these cases of reinfection suggest) that a patient’s second entanglement with COVID-19, the disease caused by the novel coronavirus, will generally be less severe than the first: “It is very likely if you got re-infected after some time it would be a milder disease, ”he said.
The same could be true for coronavirus vaccines, once they are developed: Even if they don’t protect people 100% from infection, vaccines could help our immune systems fight better against this. disease.