After health officials in Hong Kong reported the world’s first coronavirus reinfection on Monday, similar reports have emerged from around the world. The Netherlands is the latest country to confirm reinfections, as the country’s National Institute for Public Health and the Environment reported at least four reinfections Wednesday.
Belgium also reported a confirmed case late Monday, just after Hong Kong’s announcement. Taken together, this brings the total number of reinfections to six worldwide.
Dutch reinfections are all mild, say authorities
Dutch health authorities report that all four reinfections appear to be mild cases. However, all four patients are over the age of 60, which increases their risk of developing severe COVID-19 symptoms. The period between the initial infection and the reinfection, according to experts, ranged from weeks to months apart.
The first patient reinfected by COVID-19 in the country is an older adult with a weakened immune system and preexisting conditions, reported local broadcaster NOS, citing virus expert Marion Koopmans of the Erasmus University Medical Center.
It’s common for COVID-19 patients to remain infected for a long time, Koopmans added. In this case, patients often feel mild symptoms before the disease flares up again. But a reinfection, such as those seen in Hong Kong and the Netherlands, requires experts to test both instances of the infection, looking at potential differences in the virus between the first and second infections.
“That someone would pop up with a reinfection, it doesn’t make me nervous,” she said. “We have to see whether it happens often.”
Health authorities also confirmed another reinfection, this time in a nursing home patient. According to Harald Wychgel, spokesperson for the Dutch agency, the person developed the reinfection roughly two months after his initial infection and is still alive today.
The remaining two cases are in Tilburg, a city two hours away from Amsterdam. In both cases, the reinfection was mild and both patients are still alive, said Dr. Jean Luc Murk, a clinical microbiologist at St. Elisabeth Hospital in Tilburg. The first reinfection in the city was a man infected by COVID-19 during the spring but was discharged later on. The man returned weeks later, reporting that he had difficulty breathing and had developed profuse diarrhea. He tested positive again for COVID-19, roughly three weeks after his initial diagnosis.
Murk knew that patients often test positive for COVID-19 weeks, even months, after an initial infection. In most cases, another positive test could mean that the infection is still waning or that there are still dead virus particles in the body. In South Korea, reports of recovered COVID-19 patients testing positive again for the virus caused an uproar in May. The Korea Centers for Disease Control and Prevention later said that the cases were “testing flukes” and not reinfections.
In this case, however, the genetic makeup of the viruses in the first and second infections was markedly different.
“Apparently, within this period of three or four weeks, this patient had contracted a second variant of the coronavirus,” he added.
On Monday, a 33-year old man in Hong Kong became the world’s first documented case of COVID-19 reinfection. The man, who was first infected with the coronavirus four months ago, was confirmed to have been reinfected after researchers found significant differences in the genetic code of the virus of the first and second infection. The man apparently picked up the coronavirus during a trip to Spain; it was detected after a test was administered at the airport – meaning he was infected with a new virus strain.
According to Jeffrey Shaman, a public health expert at Columbia University in New York, the reinfections shouldn’t be a cause for alarm at this point. This is because reinfections represent a relatively smaller percentage of the global COVID-19 caseload.
“However, it remains very, very concerning – and this does nothing to dispel that – that we may be subject to repeat infection with this virus,” he said.
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