Coronavirus survivors may not be getting "immunity passports" after all. The idea—which has gained some ground in Europe—is that passport holders would be immune to COVID-19 and able to re-enter society. But the World Health Organization warned Friday that there's "no evidence" of infected people developing antibodies that protect them against another infection, the BBC reports. "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,'" WHO said in a statement. In fact, the world-health body warned that passports could make matters worse if holders "assume that they are immune" and "ignore public health advice."
Britain is among countries toying with the immunity-passport idea, per the Guardian, but the science seems far from certain. Reports from South Korea and China describe patients getting reinfected after they had apparently recovered; one expert says the virus might even "reactivate" itself. Most studies do show antibodies in the blood of COVID-19 survivors, but some antibody levels are low, which suggests that T-cells, another factor in the body's immune system, might be a vital element of recovery. Belgian virologist Marc Van Ranst warns that immunity passports might also be faked, and people might purposely infect themselves to get one. "This is just not a good idea," he tells the BBC. "It is an extremely bad idea." (Read more coronavirus stories.)