Levels of protection: Monitoring neutralizing anti-S1 specific antibodies

• The amount of neutralizing anti-S1 specific antibodies continuously decreases after vaccination
• Antibody monitoring is particularly helpful for immunosuppressed patients and elderly people since their immune response to SARS-CoV-2 after vaccination is found to be significantly weaker compared to the general population
• Antibody monitoring enables effective post vaccination surveillance

SYNLAB recommends evaluating individuals’ level of protection based on antibody monitoring. According to available medical data, own observations, and those of medical centres, the amount of neutralizing anti-S1 specific antibodies is a good quantitative marker for the overall magnitude of the body’s anti SARS-CoV-2 immune response. The amount of neutralizing anti-S1 specific antibodies decreases over time.
Preliminary results from ongoing clinical studies (1) imply that a threshold of ≥ 300 binding antibody units per millilitre (BAU/ml) (2) may be used as guidance for a level of protection against SARS-CoV-2.

To examine the initial immune response, SYNLAB recommends:

• Antibody testing four weeks after the second vaccination dose.
• Depending on this initial response, follow-up testing six to nine months later.

(1)
Science 2021, https://www.science.org/doi/10.1126/science.abj0299
JAMA 2021, https://jamanetwork.com/journals/jama/fullarticle/2779852
Am J Transplant 2021, https://onlinelibrary.wiley.com/doi/10.1111/ajt.16607
Am J Transplant 2021, https://onlinelibrary.wiley.com/doi/10.1111/ajt.16615
Nature 2021, https://www.nature.com/articles/s41586-021-03739-1
MedRxiv 2021, https://www.medrxiv.org/content/10.1101/2021.08.24.21262415v1

(2)
Value based on examination with Abbott technology only.