Story at a glance
- The coronavirus pandemic has forced many people to stay at home and closed most businesses.
- Some countries are considering issuing “immunity passports” to people who have recovered from COVID-19.
- In theory, this strategy could work, but testing may still be too unreliable.
The coronavirus pandemic has now shut down the activities and economies in many countries that are experiencing increasing numbers of COVID-19 cases. Experts are thinking about strategies for opening up once things start slowing down.
A few countries have started considering issuing “immunity passports” or some kind of certificates indicating a person has immunity to COVID-19. Although in theory this is a strategy that could work, it still relies on several factors for it to work properly and safely.
What is an “immunity passport”?
The idea for the “immunity passport” or a “back to work” pass is this: If you’ve been infected with SARS-CoV-2, the virus that causes COVID-19, and recover, then you have immunity that will protect you from getting the disease again for some amount of time.
What we don’t know for certain with COVID-19 is whether people do have immunity once they’ve recovered and how long that immunity would last.
How would you get an “immunity passport”?
To be able to show that you have immunity to issue an immunity passport, we’d also need reliable antibody testing, which tells you if your body has the antibodies specific to SARS-CoV-2 because you fought off the coronavirus. “Another type of test, which will prove critical to identifying possible ‘exit strategies’ for countries in various levels of lockdown, does not look directly for the virus, but rather looks for specific proteins that a person’s immune response produces after being infected,” says Claire Standley at the Center for Global Health Science and Security at Georgetown University.
Antibody testing is being developed, may already be available in some hospitals to staff and could be available for the general public within weeks. “Typically, if a person has been infected, it takes about a week or longer for antibodies against the virus to appear in the blood,” says Louis Mansky, the director of the Institute for Molecular Virology at University of Minnesota Twin Cities. Even if you weren’t tested for SARS-CoV-2, if you are tested for the antibodies, that could tell you that you at some point had the virus. If you are healthy, then that could mean that you can go back to your normal activities.
These tests are new and present their own challenges. Many of the tests are at-home test kits, which depends on the user being able to follow the instructions correctly. There’s also the issue of the quality of the testing kits to consider. In the United Kingdom, there’s concern that their at-home kits are unreliable. Another challenge is we don’t know if people who were asymptomatic will have enough antibodies in their bloodstream to pass the antibody testing.
Now, how long that immunity lasts is unknown. Is it similar to other coronaviruses like severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). This study suggests the average length of immunity for SARS is two years. Another issue is there have been reports of people who’ve recovered being tested positive again after some time, for example in South Korea, according to Reuters. Lastly, immunity protects the person from developing illness when infected but may not necessarily prevent them from infection.
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How would this help us in the response to the coronavirus pandemic?
If everything works, the antibody tests and the assumption that recovered people get enough immunity to not get COVID-19 again, then immunity passports would help us get out of stay-at-home orders and economic shutdown.
In theory, people who have an immunity passport could safely return to work because they would not get sick again and start passing the virus around. As tests become available, then business and activity could slowly return to normal.
That word again...unprecedented
Something like this hasn’t been done before because we haven’t had a pandemic of this scale and level of shutdown. Attempting to issue some kind of immunity certificate to millions of Americans would be unprecedented. Some experts think that it may be too soon to consider it. “In a situation where the prevalence of people with antibodies in the population is quite low — probably no more than around ten per cent of people — even if you’ve got a highly, highly specific test, it is still going to give you quite a lot of false positives,” says health psychologist Robert West at University College London to WIRED. “That means the government cannot say to people – because you’ve got this test result, you’ve got the antibodies.”
The antibody tests themselves will need to go through testing to prove that they can effectively give correct results. We have to be very careful if we are going to implement immunity certificates because there could be serious implications. “Imagine the psychological state of a person who thought they were in the all clear and has gone back to work in a care home and ended up killing several people,” says Susan Michie at University College London to WIRED. “We would want people to understand the benefits of having these tests, along with the uncertainty, and we don’t want these people to turn into a group like the anti vaccination groups. That could be very damaging.”
For up-to-date information about COVID-19, check the websites of the Centers for Disease Control and Prevention and the World Health Organization. For updated global case counts, check this page maintained by Johns Hopkins University.
You can follow Chia-Yi Hou on Twitter.
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