There's still a lot that scientists don't know about COVID-19, and one of the major questions that they're trying to resolve is whether or not people gain immunity after contracting and recovering from the virus.
Now, a new report from the World Health Organization warns that there doesn't appear to be enough evidence to support the idea that people cannot become reinfected with the disease, as Reuters reports.
"There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection," it said.
The finding jeopardizes efforts around the world to allow people to return to work once they've been infected.
Some governments, including the U.S., are considering the idea of issuing "passports" or other sorts of identification that would allow people to return to work or go out in public if they have had the novel coronavirus.
China has implemented a system that issues an individual a color code based on whether they've had the disease or have been exposed to someone who has had the disease. Those who have recovered get a green light to enter public spaces and move freely. Those who have been exposed to someone with COVID-19 are quarantined.Chile announced plans to issue "passports" to people who have recovered from the disease.
Dr. Anthony Fauci, a leading immunologist in the U.S. and head of the National Institute of Allergy and Infectious Diseases, said that the government was considering the idea of issuing identification for those who have recovered from the virus, as The Inquisitr previously reported.
Many states are waiting on reliable antibody testing as part of their plans for re-opening their economies.
But the WHO shed some doubt on whether these measures would work.
"Some governments have suggested that the detection of antibodies to the SARS-CoV-2, the virus that causes COVID-19, could serve as the basis for an 'immunity passport' or 'risk-free certificate' that would enable individuals to travel or to return to work assuming that they are protected against re-infection," the WHO said.
The WHO said that while most studies show that people do, in fact, have antibodies after recovery, some people seem to have low levels of the types of antibodies that would neutralize the disease and prevent reinfection, "suggesting that cellular immunity may also be critical for recovery."
So far, 2.83 million people have contracted the coronavirus, with nearly 800,000 confirmed recoveries. Over 198,000 people have died.