This is a summary, written by members of the CITF Secretariat, of:

Grunau B, Prusinkiewicz M, Asamoah-Boaheng M, Golding L, Lavoie PM, Petric M, Levett PN,   Haig S, Barakauskas V, Karim ME, Jassem AN, Drews SJ,  Sediqi S, Goldfarb DM. Correlation of SARS-CoV-2 Viral Neutralizing Antibody Titers with Anti-Spike Antibodies and ACE-2 Inhibition among Vaccinated Individuals. Microbiol Spectr. 2022 Sep 19;0(0):e01315-22 DOI: https://doi.org/10.1128/spectrum.01315-22.

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

Live viral neutralizing antibody titers are widely accepted as a good measure of immunity, yet conducting the assays are time-consuming and laborious making them suboptimal for population level measurements. CITF-funded researchers, including Drs. Brian Grunau, Pascal Lavoie and David Goldfarb (University of British Columbia), published a paper in Microbiology Spectrum that demonstrates a correlative relationship between live viral neutralizing antibodies – the gold standard for evaluating the effectiveness of antibodies to block infection – and other surrogate measurements of SARS-CoV-2 anti-spike, anti-RBD and anti-N antibodies. These latter measurements, such as high-throughput serological assays that can provide qualitative (yes/no) or quantitative (numerical) outputsare less time-consuming and labour-intensive.

Researchers determined that antibody levels and ACE-2 receptor binding capacity were directly correlated with overall live virus neutralization capacity. They hypothesized that antibody maturationAntibody maturation refers to how, over time, the immune system selectively produces antibodies that more effectively bind to the SARS-CoV-2 spike protein., which continues months post-vaccination, may be involved in the stronger correlation with live virus neutralizing capacity.

The researchers analyzed 120 samples from the COVID-19 Occupational Risks, Seroprevalence and Immunity Among Paramedics in Canada (CORSIP) study (collected between January 25, 2021 and July 14, 2021) from individuals vaccinated with two doses of an mRNA vaccine (short or long interval between doses) without prior infection to establish a statistical correlation between the concentration of anti-spike, anti-RBD and anti-N antibodies and their ability to neutralize live ancestral SARS-CoV-2 virus.