Scientists in the Netherlands and Belgium have reported more cases of patients catching Covid-19 a second time, coming after the first such case of reinfection was reported out of Hong Kong on Monday.
In the Netherlands, an elderly patient with a weak immune system tested positive for coronavirus a second time, virologist and government consultant Marion Koopmans told Dutch radio on Tuesday.
Each Covid-19 infection has a "unique genetic fingerprint," the virologist explained, with the genome of the second infection differing markedly from the patient's first.
This indicated the second infection was not a flare-up of the first, Koopmans said.
"We know from other respiratory infections that you are not immune your whole life, and we don't expect that from Covid-19 either," Koopmans said.
It would still have to be established whether the reinfection was an isolated case or the norm.
Also in Belgium
A reinfection was also recorded in Belgium, where a patient caught Covid-19 three months after recovery, with the virus displaying 11 mutations the second time, virologist Marc Van Ranst told broadcaster VTM on Monday evening.
"This is not good news," Van Ranst said, adding that he hoped this was an isolated case and immunity would last longer than a few months.
On Monday, scientists in Hong Kong offered the first proof of a patient who had recovered from Covid-19 and was reinfected, suggesting the coronavirus may persist in the human population, similar to other cold-associated human coronaviruses.
Some six months after the emergence of the virus, little is known so far about reinfection and few studies have been carried out on people who have been infected twice.
