Can You Be Immune to COVID-19?

One of the ways countries have been looking at easing lockdown restrictions as a result of the COVID-19 pandemic is by issuing "immunity passports".

The idea is that those who have had the disease, could develop antibodies and therefore immunity, allowing them to go back to work.

It's an idea mooted in a number of countries, including the U.K. and Germany, which are fighting the pandemic. Increasingly, people have come to assume that once you've had the virus, you're immune.

But can you be immune to COVID-19?

Professor David Heymann, an infectious disease expert based at the London School of Hygiene and Tropical Medicine and former assistant director of the World Health Organization (WHO) has warned against the idea people are immune, claiming it is "too early to tell if people can develop immunity."

He told Newsweek: "We've seen with other viruses that in the short term people may develop immunity and can appear to be protected one cold season for example, but the next season they are infected with the same virus."

For example, vulnerable people are advised to get a flu jab every year to negate any mutations in the virus. There is no current way to become fully immune from the flu but existing antibodies can create partial protection or ease symptoms.

Professor Heymann also cautioned against the idea that developing immunity would mean a complete recovery for people with the virus.

He said: "You could have an enhanced antibody response which actually causes harm to the body.

"Does that really cause an immunity and, if it does, for how long? And will that immunity somehow be an immunity which we are not expecting and has some side effects?

"So that's why the World Health Organization is recommending that people not use an immune status as a means of saying you're safe to go back to work because that's not at all clear."

The WHO has been quite clear about its view of immunity passports:

"There is currently no evidence that people who have recovered from Covid-19 and have antibodies are protected from a second infection," it said in a statement on April 25.

"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'."

Professor Heymann also said we did not know for certain yet if the current tests showing whether somebody has developed antibodies to the COVID-19 are accurate.

He said: "The tests that are available are not considered yet to have their sensitivity and specificity known. They're being examined for that to see if they're sensitive enough to pick up all infections and if they're specific enough to not pick up things like other coronaviruses instead of just COVID-19."

Professor Heymann also drew attention to studies in China that showed that people who have mild infections haven't "produced enough antibodies to be detected in the kind of testing that they are doing."

He said: "We just don't understand enough about the antibodies and the protection they offer to say that this can be used for what some people are calling an immunity passport to go back to work."

COVID-19 immunity
A number of countries have considered "immunity passports" as a way for those who have recovered to return to work Getty

Professor Heymann also said that immunity was no guarantee that you were not a carrier of the virus in your nose.

He said: "For example, with meningitis which is transmitted through the nose and through coughing and sneezing, people can be immune to that bacteria, yet carry the bacteria in their nose and infect others.

"And the same is true for polio, if you're immune to polio you can still carry the virus that causes polio in your gut even though it doesn't infect you it could affect others."

Polio has now been effectively eradicated after the successful deployment in a vaccine, except in areas of the world with the poorest and most marginalized communities.

But we are a long way away from being able to say that the coronavirus pandemic has been "solved".

Professor Heymann also drew attention to how MERS coronavirus, which affects camels, is still carried in the nasal passage of camels that are immune.

He said: "We have a precedent in the animal kingdom with a coronavirus and is that same thing happening in humans, we just don't know yet."

Dr. Mohammed Abbas Khaki also cautioned against the use of antibody tests.

He said: "Everybody thinks the new antibody tests that are arriving will be really powerful and important, but there are still issues with the test we need to consider.

"The test can tell you if you've had it (COVID-19) but it doesn't necessarily mean that you're immune."

Dr. Larisa Corda, who works on the frontline in the battle against COVID-19 in intensive care units also warned that people believing they are immune gives them a false sense of security.

She said: "The antibody test is really a measure of whether you had the virus before and whether you theoretically developed immunity to it by developing antibodies in response to the initial antigen trigger from COVID-19.

"So that takes a little bit more time to develop, but theoretically if you've got these antibodies they can last for weeks or months in your serum.

"Now what hasn't been proven yet is that even if you've got antibodies that you will necessarily be immune to COVID-19."

Dr. Corda said people could be given a false reassurance that they may be immune and don't have to follow social distancing guidelines, which could give rise to a second wave of infection.

Can You Be Immune to COVID-19? | World