The WHO warned governments on Saturday to not issue 'immunity passports' for recovered coronavirus patients since there is "no evidence" to indicate they developed antibodies protecting them from reinfection.

"The use of such certificates may therefore increase the risks of continued transmission," the UN agency said in a scientific brief.

Dr. Anthony Fauci said on CNN earlier this month the federal government was weighing whether it should issue the immunity passports.

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The World Health Organization on Saturday discouraged governments from issuing immunity passports, warning there was still "no evidence" to indicate recovered coronavirus patients are shielded from future infections.

The agency said in a scientific brief that it's still too early to tell whether patients who recovered from the virus developed antibodies giving them immunity.

"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 WHO said. "People who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice."

It added: "The use of such certificates may therefore increase the risks of continued transmission."

Leaders around the world are starting to weigh reopening their economies after several weeks of a shutdown aimed at curbing the spread of the virus, which has killed nearly 200,000 people around the world.

Some have debated issuing so-called immunity passports designed to allow people who recovered to go back to work.

Read more: Tests that can tell who's had the coronavirus are crucial to reopening the country. Here are the companies racing to bring them to the US healthcare system.

Chile became the first country to issue the passports, The Washington Post reported. People receiving either the digital or physical cards will be exempted from quarantines or other social restrictions.

The UK is also mulling whether it should take a similar step.

Such certificates are tied to coronavirus antibody tests, which raise concern among public health experts since their quick development is leading to faulty results.

In the US, Dr. Anthony Fauci, the nation's leading infectious disease expert, said on CNN earlier this month that the idea of the passports "might have some merit under certain circumstances" and it was under consideration at the time.

Read more: 'It's a disaster': More than 100 companies are pumping unapproved coronavirus tests into the US healthcare system

The federal government has entered discussions with AI startup Onfido about rolling out the passports across the country, Business Insider's Martin Coulter previously reported.