Considerations for the use of antibody tests for SARS-CoV-2 – first update

Key messages

• At present, antibody tests are mostly used in research studies (mainly sero-epidemiological) at population level rather than for individual diagnosis of COVID-19 cases. 
• A positive antibody test result can indicate a previous infection or vaccination but cannot be used to determine whether an individual is currently infectious or protected against infection.
• In the absence of a positive diagnostic test result, antibody tests cannot determine the time of infection.
• The antibody titres that correlate with protection from infection are currently unknown.
• There are a variety of antibody tests available and it is extremely difficult to compare their results due to the diversity and lack of standardisation.
• Antibody tests that target the spike protein are unable to distinguish between those who have been previously infected and those who have received at least one dose of a SARS-CoV-2 vaccine.
• There is a risk that the antibodies detected by the commercial tests currently in use will not prevent infection with newly emerging SARS-CoV-2 variants.