There is no evidence that patients who once had COVID-19 are immune from being infected again by the virus that causes the disease, the World Health Organization (WHO) said.
The virus is a novel coronavirus that emerged from mainland China last year. Its technical name is SARS-CoV-2. The virus causes COVID-19, a disease that can be deadly in a small percentage of patients.
Tests for detecting antibodies to the CCP virus in people still need further validation to ensure accuracy and reliability, according to the WHO.
Inaccurate tests in the context of a push from some quarters for documents attesting to alleged immunity could lead to people who were actually infected with the virus being labeled as negative, while designating some people who haven’t been infected with the illness as positive.
“Both errors have serious consequences and will affect control efforts,” WHO stated.
People who are told they’ve been infected in the past may assume they’re immune to a second infection and ignore public health advice. The use of certificates outlining alleged immunity “may therefore increase the risks of continued transmission.”
Another concern is whether the tests are distinguishing between past infections from the CCP virus and those caused by six other human coronaviruses, including the viruses that cause Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
“People infected by any one of these viruses may produce antibodies that cross-react with antibodies produced in response to infection with SARS-CoV-2,” the health group said.
Chile said last week it would use results from antibody tests to determine who could immediately start working again after lockdown measures were imposed to try to slow the spread of the CCP virus. It described documents those people would receive as “health passports.”
The idea is also being considered in other countries, including in Germany and the United Kingdom.