April 25 (UPI) -- There is no evidence that coronavirus patients who have recovered won't catch the virus again, the World Health Organization said.
The agency issued the statement Friday after some governments suggested recovered COVID-19 patients could be issued an "immunity passport" to return to travel or "risk-free certificate" to return to work.
In general, the immune system creates antibodies from fighting off infection, which lower risk for re-infection, but it remains to be seen whether that holds true for the novel coronavirus.
"There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection," the WHO statement said.
The U.N. agency added that if people receive such certificates they "may ignore public health advice," and "increase the risks of continued transmission."
Among the governments recommending such measures, Chile announced plans to issue "immunity passports" to people who had recovered from the virus so that they could return to normal activities.
In the United States, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, suggested earlier this month that a method of identifying people who have recovered or are vaccinated could be useful in the United States.
Many countries have begun testing for antibodies in areas most at risk, such as New York, which ramped up testing earlier this week. The data has provided information on the percentage of people with antibodies, but not whether they are immune to secondary infection. WHO said it continues to analyze evidence on antibody response to COVID-19 infection and will update as new evidence becomes available.