Senior World Health Organization officials say there is no evidence that people who have survived a bout of coronavirus become immune from the deadly disease and cannot pass the infection on to others.
The coronavirus pandemic continues to spread across the world with breathtaking speed and no immediate end in sight.
Anxious governments increasingly are grabbing on to the hope that those who have become sickened by this infectious disease will become immune and not pass it on to others.
They are pinning their hopes on serologic tests that look for antibodies in a person’s immune system to clarify the number of people who have been exposed to the virus. Knowing this, they argue, would allow them to send these people back into the workforce without risk of their getting infected or of infecting others.
But head of WHOs emerging diseases and zoonosis unit, Maria Van Kerkove said these serologic tests may not be able to provide the information governments are seeking.
“Right now, we have no evidence that the use of a serologic test can show that an individual is immune or is protected from reinfection. What the use of these tests will do will measure the level of antibodies and it is a response that the body has a week or two later after they have been infected with this virus,” she said.
These tests will be able to measure the level of antibodies, but Van Kerkove said that does not mean that somebody with antibodies is immune to the disease.
Executive Director of WHO health emergencies, Michael Ryan, cautions countries to be prudent and not fix on these tests as a way of establishing the status of an individual. He said there is a lot of uncertainty about the effectiveness of the available tests.
“Nobody is sure whether someone with antibodies is fully protected against having the disease or being exposed again. Plus some of the tests have issues of sensitivity; they may give a false negative result and we may actually have someone who believes they are seropositive or they are protected actually in a situation where they may be exposed and in fact they are susceptible to the disease,” he said.
Ryan said a lot of work still lies ahead to standardize the tests and make sure they are validated. He said great care must be taken to ensure they are not misused but are used in ways that enhance public health.