Cyprus Mail 23 April - by Nick Theodoulou
Reports on Wednesday indicated that a small number of Covid-19 patients in Paphos recovered from the virus, tested negative, but upon later checks retested positive.
Such cases have been reported in China and most notably in South Korea.
“It has happened in two to three cases in patients in Paphos,” CyBC reported late on Wednesday night.
Such cases cause concern not least amongst governments which pin their hopes on easing lockdowns by large parts of the population developing an immunity to the virus.
No official from the health ministry was immediately available for comment on events in Paphos, but the South Korea experience may give a clue as to what might have occurred.
South Korea, which has received international praise for its efforts against the virus, has identified 163 out of its 7,829 recovered patients who tested positive after recovering.
The burning question, however, is what may cause a person to recover, test negative but then later test positive once again for Covid-19.
Kim Woo-joo, professor of infectious diseases at Korea University Guro Hospital, identified two possible causes for such cases.
“Relapse is when the virus gets treated, the symptoms go away and the patient even tests negative,” he said. “But it’s just that the number of virus copies is so small that the PCR test kits can’t detect it.”
He explained that about 3,000 copies of the virus are needed for the test to indicate a positive result.
“If there is less than that the test comes out as negative, even if you still have the virus,” Woo-joo said.
A person may be discharged but the virus will replicate and the virus copies may go up from 3,000 to 4,500 and a person may then test positive.
Such a scenario is defined as a relapse.
A reinfection, however, is when a person has completely got rid of the virus from their body and is then reinfected.
Top officials from the Korean Centers for Disease Control and Prevention (KCDC) said in recent briefings that the most likely cause is remaining viruses in a patient reactivating.
Jeong Eun-kyeong, director of KCDC, said the virus may have been reactivated rather than the patients being reinfected.
