Policymakers have another reason to scramble to deploy antibody tests: they could indicate whether someone is immune to SARS-CoV-2. With around 3 billion people globally under lockdown, pressure is mounting to re-open national economies. In recent weeks, several politicians have proposed the idea of “immunity passports” or “immunity certificates” to identify people who have had the virus and therefore gained immunity to it and could re-enter the workforce again. Officials in Germany, the UK, Italy, and the US are already discussing such proposals.
The success of such a program hinges on whether everyone who has contracted SARS-CoV-2 actually develops antibodies, whether those antibodies protect against secondary infections, and if so, how long the antibodies hang around in the body.
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In MERS, the levels of neutralizing antibodies have been observed to fade after three years. For the less deadly, cold-causing coronaviruses, neutralizing antibody levels also fall off in that two-to-three-year range.
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Although it may be true that most first-time exposures to dangerous pathogens will result in protective immunity, it’s scientifically difficult to make the claim that any given person will be immune to the virus if they reach a certain score on an antibody test—not to mention, such predictions carry various legal and ethical issues.
