In South Korea there have been over 10,000 confirmed cases of COVID-19 with 245 deaths, that is a 2.3% fatality rate which is lower than the 3.4% averaged as stated by W.H.O. In South Korea a total of 277 patients were reported to have fallen ill for a second time, as with China and Japan.
The apparent reinfections prompted concerns over the virus mutating at a rate so quickly that people would not be able to build immunity against it. The following genetic analyses of the virus did not yield any substantial changes in the virus that would effectively disguise it from the immune system.
As a result of these reports W.H.O has warned against using “immunity passports” as a way of allowing people to return to work simply because they have antibodies for the virus in approaches for countries to begin to lift restrictions and lock downs in a targeted manner to resume economic activity. Such passports would be issued to those who have overcome COVI-19 infections and tested positive for antibodies for the virus based on the assumption of them being immune, but they rely on the accuracy of the testing.
In an update to this guidance WHO warned that there was “no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection”. It was also not expected that the PCR testing used to check for blood antigens for the actual particles of the virus itself would have issues.
The South Korean CDC has found that the PCR test results for the suspected relapsed patients were false positives, warning that the tests were not able to distinguish between live traces of the virus and the harmless dead samples that remain after the patient has recovered.
W.H.O is warning that immunity certification will depend upon the accuracy and reliability of the testing that is being rapidly developed, which under normal circumstances take years of trials to determine.
“People who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice,” the WHO warned. “The use of such certificates may therefore increase the risks of continued transmission,” its guidance added at the time, although this guidance is currently being kept under review.
Unlike other viruses like HIV and chickenpox that can break into the nucleus of human cells to stay latent for years before reactivating, COVID-19 stays outside of the host’s cell nucleus according to the South Korean CDC.
“This means it does not cause chronic infection or recurrence,” explained Dr Oh Myoung-dong, the head of the CDC committee, meaning it is unlikely for patients to relapse in this fashion.
However, if the virus mutates further it could be possible that COVID-19 could infect people who had previously overcome it in the future, in a manner similar to that of the flu.