Several nations and businesses have pioneered the idea of using “immunity passports” or “safe certificates” to allow people who have contracted and recovered from the virus to travel or return to work, assuming they are now protected against a second infection. .
But the WHO said in a scientific briefing that although studies have shown that people who have recovered from SARS-CoV-2 have antibodies, some “have very low levels of neutralizing antibodies in their blood”.
“As of April 24, 2020, no study has evaluated whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection with this virus in humans,” he added.
The Geneva-based United Nations health agency has also reported that these documents rely on laboratory tests that detect antibodies to the virus, but that these rapid immunodiagnostic tests currently “require validation additional to determine their accuracy and reliability ”.
He also warns that passports could increase the risk of continuous transmission because “people who assume they are immune to a second infection because they received a positive test result may ignore public health advice.”
The warning comes after Chilean authorities announced earlier this week that they plan to use “immunity passports” to free people from blockages.
Ed Bastian, the CEO of Delta Airlines, also said earlier this week that “immunity passports” could be used to reassure passengers about the safety of air travel.