Last reviewed 23 August 2021

Information has been published by the Department of Health and Social Care (DHSC) for healthcare workers in primary care settings on the types of Covid-19 antibody tests available and how to interpret results.

The guidance helps healthcare workers to interpret results, and discuss antibody testing, vaccination, infection and risk with patients. It has been issued because, as more people access antibody tests, there is an increasing chance that people approach primary care services for advice. It should give guidance to professionals but is not intended to direct clinical care.

Testing for antibodies raised against SARS-CoV-2 can detect evidence of past infection and/or response to vaccination, be used to monitor disease progression or aid diagnosis of Long Covid. Also, nationally, antibody testing is being used to understand vaccine effectiveness, monitor the impact of variants of concern (VOCs) and estimate prevalence of infection.

The guidance says antibodies waning below detectable range over time will likely not result in loss of protection from severe disease but infections are likely to be possible. Different variants are more likely to evade any protection afforded by previous infection by another variant or by vaccination but disease severity is still likely to be mitigated.

However, the guidance says that the presence of detectable circulating antibodies will almost certainly result in a mitigation of disease severity on exposure to virus “but antibody status alone cannot be used to confidently assure against protection from infection”.

Over 99% of people generate antibodies after a full schedule of vaccination and this response is anticipated to remain detectable for approximately ten months. Waning mechanics are not fully understood and vary between individuals.

The DHSC information is available here.