COVID-19 antibody testing and ‘immunity certification’
Information relevant to an individual’s risk of infection/transmission is provided by a growing range of tests, which have differing performance characteristics. The tests that are principally in view are antibody (serological) tests, but other biomarkers may also be relevant. Individual test results can be interpreted in the light of other relevant information to provide, in effect, a personal risk profile. Confidence in this measure will depend partly on the performance characteristics of the test or tests, and the range of biological and circumstantial factors (many of which are unknown) that contribute to protection and susceptibility.
Antibody tests are being rolled out for the purpose of research, which is needed to establish the background prevalence of past infection and thus the confidence that can be placed in individual test results. Health and social care workers are currently being offered antibody tests as part of research studies. Organisations and businesses may have other reasons to want their staff to be tested, for example, to manage infection risk, and to provide reassurance to colleagues, clients and customers.
Individual citizens may also have incentives to take tests to manage their personal risk of infection (for example, in relation to susceptible family members) or to gain access to goods or services for which a positive test result may be required. Some direct-to-consumer tests are becoming available that claim to give customers information about their antibody status (i.e. the kind of information that will be available to those who participate in research).