(CNN) – The World Health Organization is warning that people who have had coronavirus are not necessarily immune by the presence of antibodies from getting the virus again.
“There is no evidence yet that people who have had Covid-19 will not get a second infection,” the WHO said in a new scientific brief.
The WHO is warning against governments issuing “immunity passports” to people who have had Covid-19, assuming they are safe to resume normal life.
“At this point in the pandemic, there is not enough evidence about the effectiveness of antibody-mediated immunity to guarantee the accuracy of an ‘immunity passport’ or ‘risk-free certificate,’” the brief said.
The WHO published the brief as guidance on adjusting public health and social measures for the next phase of the COVID-19 response.
“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 use of such certificates may therefore increase the risks of continued transmission,” the WHO said.
The health agency says it is reviewing evidence on antibody responses to SARS-CoV-2, the virus that causes Covid-19-infection. The brief says “most” of the studies show that people who have “recovered from infection have antibodies to the virus.”
But as of yesterday, no study has “evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans.