Patients who have recovered from COVID-19 may not be immune from contracting the disease again, UN scientists warned on Saturday.
The alert, in a scientific briefing from the World Health Organization (WHO), is a blow to countries aiming to use proof of coronavirus antibodies to ease restrictions on movement, restart their struggling economies and get their people back to work.
Instead, the scientists said, people who mistakenly believed they were immune may ignore advice on social distancing, leading to a second spike in the pandemic.
Some governments, wanting a gradual return to work and the resumption of economic activity, have put forward the idea of issuing documents attesting to the immunity of people on the basis of serological tests revealing the presence of antibodies in the blood.
But the effectiveness of an immunization thanks to antibodies has still not been established and the available scientific data do not justify the granting of an “immune passport” or a “certificate of absence of risk,” warns the WHO.
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.”
“People who assume that they are immune to a second infection because they have received a positive test result may ignore public health advice,” the WHO said.
“The use of such certificates may therefore increase the risks of continued transmission.”
The WHO warning came as the number of people infected by the virus worldwide approached 3 million, and the death toll passed 200,000.
And there was evidence in Iran that the scientists’ fears may be justified. Since April 11, authorities have been gradually allowing the reopening of businesses that were closed to curb the spread of the virus. But Iran reported 1,134 new virus cases on Saturday, increasing the total to 89,328, and the death toll rose by 76 to 5,650.
Alireza Zali, the anti-coronavirus coordinator for Tehran, criticized “hasty reopenings,” which he said could “create new waves of sickness in Tehran and complicate efforts to bring the epidemic under control.”
Health Ministry spokesman Kianoush Jahanpour said it was clear that social distancing and hygiene measures needed to remain in place.
The ministry’s infectious diseases department head, Mohammad Mehdi Gouya, warned of “signs of a fresh outbreak” in provinces such as Gilan and Mazandaran in the north and Qom in central Iran, “where we made great efforts to control the epidemic.”
Governments are struggling to limit the economic devastation caused by the virus, which has left half the world’s population under some form of lockdown.
The UN has joined world leaders to speed up development of a vaccine, but effective treatments for COVID-19 are still far off. But with signs that the disease may be peaking in the US and Europe, governments are starting to ease restrictions.
In the UK, where Prime Minister Boris Johnson is expected to return to work on Monday after falling victim to the virus, the death toll passed the milestone of 20,000, which Home Secretary Priti Patel described as “a deeply tragic and moving moment.”
Saudi Arabia reported 1,197 new virus cases on Saturday, increasing the total to 16,299, and the death toll rose by nine to 136.