The idea is that those who have had the disease could develop antibodies and therefore immunity, allowing them to return to work.
This is an idea that has been raised in a number of countries, including the United Kingdom and Germany, which are fighting the pandemic. More and more people are assuming that once you get the virus, you are immune.
But can you be immune to COVID-19?
Professor David Heymann, infectious disease expert based at the London School of Hygiene and Tropical Medicine and former deputy director of the World Health Organization (WHO), warned that people are immune, saying that it is “too early to say if people can develop immunity. “
He told Newsweek: “We have seen with other viruses that in the short term people can develop immunity and may appear to be protected in one cold season, for example, but the following season, they are infected with the same virus. “
For example, vulnerable people are advised to get the flu shot every year to reverse any mutation of the virus. There is currently no way to become fully immune to the flu, but existing antibodies can create partial protection or relieve symptoms.
Professor Heymann also warned that developing immunity would mean full recovery for people with the virus.
He said, “You might have an improved antibody response that actually damages the body.
“Does this really cause immunity and, if so, for how long? And will this immunity somehow be an immunity that we do not expect and that has side effects?
“This is why the World Health Organization recommends that people do not use immune status as a means of saying that you can return to work safely, because it is not at all clear. “
The WHO has been quite clear about its vision of immunity passports:
“There is currently no evidence that people who have recovered from Covid-19 and who have antibodies are protected from a second infection,” he said in a statement on April 25.
“At this stage of the pandemic, there is not enough evidence of the effectiveness of antibody-mediated immunity to guarantee the accuracy of a” passport of immunity “or” certificate without risk “.”
Professor Heymann also said that we were not yet sure whether the current tests showing whether someone had developed antibodies to COVID-19 were accurate.
He said: “The available tests are not yet considered to have their known sensitivity and specificity. They are being examined to see if they are sensitive enough to detect all infections and if they are specific enough not to pick up things like other coronaviruses instead of just COVID-19. “
Professor Heymann has also drawn attention to studies in China which have shown that people with mild infections have “not produced enough antibodies to be detected in the type of test they do.”
He said, “We just don’t understand enough of the antibodies and the protection they offer to say that it can be used for what some people call an immunity passport to return to work. “
Professor Heymann also said that immunity does not guarantee that you are not carrying the virus in your nose.
He said, “For example, with meningitis that spreads through the nose and through coughing and sneezing, people can be immune to this bacteria while carrying the bacteria in their noses and infecting others.
“And the same is true for polio, if you are immunized against polio, you can still carry the virus that causes polio in your gut even if it does not infect you, it could affect others. “
Polio has now been effectively eradicated after the successful deployment of a vaccine, except in areas of the world where the poorest and most marginalized communities live.
But we are far from being able to say that the coronavirus pandemic has been “resolved”.
Professor Heymann also drew attention to how the MERS coronavirus, which affects camels, is still carried in the nasal passage of immune camels.
He said, “We have a precedent in the animal kingdom with a coronavirus and it’s the same thing that happens in humans, we just don’t know it yet. “
Dr. Mohammed Abbas Khaki also warned against the use of antibody tests.
He said, “Everyone thinks that the new antibody tests coming up will be really powerful and important, but there are still problems with the test that we have to consider.
“The test can tell you if you have had one (COVID-19) but that doesn’t necessarily mean that you are immune. “
Dr. Larisa Corda, who works on the front line in the battle against COVID-19 in intensive care units, also warned that people who thought they were immune gave them a false sense of security.
She said: “The antibody test is really a measure of whether you have had the virus before and whether you have theoretically developed immunity against it by developing antibodies in response to the original antigenic trigger of COVID-19.
“So it takes a little longer to develop, but theoretically, if you have these antibodies, they can last for weeks or months in your serum.
“Now what has not yet been proven is that even if you have antibodies, you will necessarily be immune to COVID-19. “
Dr. Corda said people may be falsely reassured that they may be immune and not have to follow social distancing guidelines, which could lead to a second wave of infection.