The World Health Organization (WHO) published a brief on April 24 which says that there is “currently no evidence” that people who have recovered from COVID-19 and have antibodies would be protected from a second infection. They would nonetheless, end up with “some level of protection,” the WHO subsequently clarified.
WHO cautioned in its brief that due to a lack of evidence, doling out “immunity passes” based on recovery from the virus could lead to people ignoring public health advice when they could still get re-infected and continue the chain of transmission.
Having a large portion of a population with antibodies that make them immune to another infection from the same virus is known as “herd immunity,” because those who have yet to be infected and lack the antibodies are conferred some level of protection because the virus cannot take hold in the population as a whole. Herd immunity is being floated in Canada and elsewhere as regions and countries seek to end lockdowns and social distancing measures.
For example, Quebec Premier François Legault stated in an April 23 press conference announcing plans to restart the economy, “The idea is to gradually – and that’s the important word – to gradually let people go out, let children go out.” Those under 60 years of age might be candidates for developing immunity, he suggested.
Canada’s Chief Public Health Officer Dr. Theresa Tam, during a press conference on April 25, said that there is insufficient evidence to back herd immunity as a way to reopen society, as Quebec’s Premier suggested.
“The idea of […] generating natural immunity is actually not something that should be undertaken,” Dr. Tam said. She called on people to be “extremely cautious” about the concept. She said that even a young person might become severely sick and end up in the ICU, “so it’s not a concept that should be supported.”
Canada’s official position is that until a vaccine is developed against the COVID-19 virus, the population will not be safe from infection.
In response to the demands of premiers for the economy to be opened after a one-month shutdown, Canada’s first ministers, including the Prime Minister, on April 24 agreed to work on a joint set of national guidelines that would lay out how to carry out the process. Trudeau said at his press briefing on April 25 that those plans do not rely on using immunity as an interim form of protection.
“In the approach that we’re taking very carefully around the provinces and across the country on looking at reopening, I don’t believe that there are any plans that hinge on certain people or individuals being immune or having immunity to COVID-19,” Trudeau said.
Some countries, such as Chile, are moving to issue “immunity passports” to those who have recovered from the virus, media reports inform. The passes would be issued to gradually exempt people from restrictions put in place to limit the spread of COVID-19, permitting them to return to work, attend mass gatherings or even travel across borders.
Dr. Tam said that without a clear understanding of immunity tests for COVID-19, it’s too early to think about issuing passes for those who might be protected.