The World Health Organisation has said that there is no evidence that people who have recovered from COVID-19 will have immunity to the disease.
Antibody tests are designed to measure if someone has been infected with a disease, but senior WHO epidemiologists have warned that there is no proof that someone is immune to COVID-19 after having recovered from it.
Dr Maria Van Kerkhove was speaking at a new conference in Geneva:
“There are a lot of countries that are suggesting using rapid diagnostic serological tests to be able to capture what they think will be a measure of immunity. Right now, we have no evidence that the use of a serological test can show that an individual has immunity or is protected from reinfection.”
She added that “These antibody tests will be able to measure that level of seroprevalence – that level of antibodies – but that does not mean that somebody with antibodies means that they are immune.”
Dr. Mike Ryan, executive director of WHO’s emergencies program said “Nobody is sure whether someone with antibodies is fully protected against having the disease or being exposed again,” while also warning that some tests have issues with sensitivity and “may give a false negative result”.
Worryingly, a preliminary study from Shanghai showed that some patients had no detectable antibody response, while others had a very high response.
And now there are concerns after some 163 patients in South Korea are testing positive for the corona virus a second time after having been diagnosed as recovered.
That means more than 2% of the recovered patients in South Korea have tested positive for the disease again.
On average it went 13.5 days between recovery and testing positive a second time, however the longest was 35 days.
Health authorities in South Korea have said it is morre likely that the infections were re-activated rather than people getting re-infected.
The Korea Centers for Disease Control and Prevention (KCDC) director Kwon Joon-Wook said that one “possible and very strong explanation” for people testing positive a second time could be that the tests are picking up remnant of the virus because the tests are so sensitive.
However, Kwon said that it comes down to this, that “We don’t know much about COVID-19.”
South Korea will be testing people who have been infected to see how much, and if any immunity can be found to the disease.