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The World Health Organization has warned against issuing “immunity passports” to people who have recovered from Covid-19, as there is no evidence that they are protected from a second infection.
The idea of issuing some form of certificate to people who have been sick with the virus, under the assumption that they would be immune to reinfection, has been gaining ground in many places, including the UK, as authorities seek ways of leaving society. economically devastating blockades.
But in a scientific information note, the WHO warned that “there is currently no evidence that people who have recovered from Covid-19 and have antibodies are protected from a second infection.”
Instead, certificates could pose a health risk by providing unwarranted guarantees of protection to individuals and their communities.
“At this point in the pandemic, there is not enough evidence on the effectiveness of antibody-mediated immunity to warrant the accuracy of an” immunity passport “or” risk-free certificate, “” the note says.
“People who assume they are immune to a second infection because they have received a positive test result may ignore public health advice. Therefore, the use of such certificates may increase the risks of continuous transmission. “
There have been reports, including from China and South Korea, of patients who appeared to have recovered from the disease testing positive again.
There are several possible explanations for those results. Jeong Eun-kyeong, director of the Korea Centers for Disease Control and Prevention (KCDC), said that instead of reinfecting patients, the virus may have been “reactivated.”
False test results could also be to blame, other experts said, or remnants of the virus may still be in patients’ systems, but not in those that pose a danger to the host or risk of infecting others.
Experts have previously expressed concern that “immunity passports” could exacerbate economic inequalities and increase transmission risks by encouraging job-desperate people to deliberately try to become infected.
The idea of separating people by immunity status also has a dark history in the United States, detailed in the New York Times by Stanford professor Kathryn Olivarius.
Until now, Chile is the only country to launch an official immunity passport scheme. Elsewhere there have been concerns that the schemes will be unreliable and impractical if only a small portion of the population has been infected.
The WHO said it was continuing to review evidence on antibody responses to the virus. Most studies have shown that people who recovered from the infection have antibodies to the virus, but it is unclear whether they provide protection.
“As of April 24, 2020, no study has evaluated whether the presence of antibodies against SARS-CoV-2 confers immunity to subsequent infection by this virus in humans,” the document said, using the formal name of the virus that Covid-19 cause.
In the four months since the virus emerged in the central Chinese city of Wuhan, it killed nearly 200,000 people and infected more than 2.8 million.
But there are still no countries where the disease is believed to be widespread enough to have created a large population of antibodies, or something akin to “collective immunity” that was once considered a policy for the United Kingdom.
Recent research from Austria, based on a representative sample of the population, found that less than 1% of people were “acutely infected” with coronaviruses, well below a level where immunity passports would make much difference to end a block.
