Research seems to indicate that people who test positive for the novel coronavirus, in spite of having already recovered, do not test positive because they have been infected a second time.
Patients that were discharged from South Korean hospitals have tested positive for the virus again. This has raised concerns, as some people think that it is possible to get infected with COVID-19 in the short term multiple times. Diagnostic tests for COVID-19, however, are based on identifying the genetic material of the virus. Testing positive does not necessarily indicate an active infection, as that would mean that the person is shedding viruses, which can cause further infections.
A report on May 19 from the Korean Centers for Disease Control and Prevention indicate that samples taken from patients who have been infected again do not have infectious viruses. The study finds that the diagnostic tests pick up on the genetic material from dead or otherwise noninfectious viruses. Their absence indicates that people are not infected and are not able to transmit the virus to other people.
Angela Rasmussen, a virologist, affiliated with the Columbia University, said that these are definitely good news. It would mean that people are not getting reinfected and COVID-19 is not activating again.
In the research, scientists have attempted to isolate infectious samples of the coronavirus taken from 108 people who tested positive to COVID-19. Every single person tested negative. Upon an examination of 23 of those patients, almost all of them were found to have neutralizing antibodies which prevent new infections from taking place, at least in the short term.
Researchers have also found 790 contacts of the 285 people who tested positive for COVID-19. Of those, a mere 27 tested positive for COVID-19. Out of those 27, 24 were cases that the researchers had already identified.