Some persons who have recovered from COVID-19 are testing positive (DK) for the coronavirus. In a study at Aarhus University, around 20 percent of 200 persons tested still had the coronavirus four weeks after they had recovered from the illness. Martin Tolstrup, Lecturer in Infectious Diseases, made the study in order to determine whether the patients had antibodies against the illness and also tested them for the virus. “We are very surprised at the high number who are still positive,” he said. The patients no longer had symptoms, but the researchers do not know whether they are infectious or how to interpret the persistence of the positive results.

“I have reached out to several other researchers, but no one knows,” continues Tolstrup. “There are reports from abroad about a reactivation of the virus.” In South Korea, some recovered patients tested negative and later tested positive. Some of the patients in Tolstrup’s study had both antibodies and the virus. Tolstrup has not seen any indication that these patients are infectious, but others are conducting contact-tracing to see whether they have infected anyone recently.

But are they infectious?

Jens Lundgren, Professor of Infectious Disease Medicine at Rigshospital in Copenhagen, is not surprised by these results. “It can take up to four to six weeks before the PCR test [for the virus] tests negative. We do not expect that it is an infectious virus.” Lars Østergaard, Professor of Infectious Disease Medicine at Aarhus University, agrees but notes that it is not certain that recovered patients cannot infect others. “If they prove to be infectious, that of course raises new questions about how we contain the virus.”

Potential superspreader event

More people who attended the Black Lives Matter demonstration (DK) on June 7 have been found to be infected. At least three additional cases have been identified. Attendees had been warned of the risk of infection before the demonstration, in which 15,000 people participated, many standing very close together and chanting. After the demonstration, they were urged to undergo a test, but it is unknown how many have done so. BLM held smaller protest demonstrations in other Danish cities as well. Political demonstrations are exempt from the limit on the number of people who may gather together.

First Danish pet with coronavirus

Several days after reports of coronavirus infections at a mink farm in northern Jutland, the virus has been identified in a dog (DK) at the same farm. It is the first time a pet in Denmark is known to have been infected. The dog’s owner was instructed to treat the dog according to the same guidelines as the people on the farm. It must “avoid contact with other animals and people outside the household,” said Mogens Jensen, Minister of Environment and Food. The Ministry does not believe that the dog will spread the infection, “but we must keep it away from sick people in the family,” said Peter K. Embarek, an expert in food-borne illness outbreaks.