By Dr. Stephen Russell, M.D., Ph.D., Chief Executive Officer, Imanis Life Sciences
After a devastating year grappling with the COVID-19 pandemic, the future is looking brighter with the rollout of highly effective vaccines. But while the number of people vaccinated is steadily increasing, unfortunately their immunity to the virus will inevitably wane over time, raising important questions for healthcare businesses, providers and the public at large: How long will vaccines provide protective immunity? Are vaccines working as expected in each person? What impact do viral variations have on vaccine efficacy?
To address these pressing questions, hospitals, clinics and private practices now have access to a new neutralization assay to help make informed decisions about vaccine deployment and to better ensure the safety of staff and patients.
A new assay accurately measures antibody levels
Neutralizing antibodies are the key determinants of immune system protection from future COVID-19. For the first time, clinically validated high-throughput assays for measuring titers of SARS-CoV-2 neutralizing antibodies are available, notably the IMMUNO-COVTM assay which was developed and validated by Imanis Life Sciences.
High-throughput virus neutralization assays like IMMUNO- COVTM accurately quantify the level of COVID-19 neutralizing activity in a simple blood sample. With this technology, it is now possible to access highly specific information that can help determine future safety protocols and provide peace of mind for business leaders, patients, employees and their families.
Periodic measurement of neutralizing antibody titers can help medical providers and their patients understand the levels of risk for a given individual or group, and how these can change over time. For example, a titer of 500 or more will provide robust protection from the SARS-CoV-2 virus, while protection is much less certain with a titer of 100 or less, making it inadvisable to take risks such as travel or participating in large or high-risk social gatherings.
Neutralization assays can also give real-time data on waning immunity in vaccine recipients. By analyzing the speed with which titers fall in any given individual, in groups of specific age ranges or with specific medical conditions, public health officials and the entire healthcare community can develop vaccine booster strategies and timelines designed to control the future trajectory of the pandemic.
Predictive models of immune protection
Armed with these new types of assays which can quantify neutralizing antibodies, researchers have been modeling the relationship between blood levels of neutralization and observed protection from SARS-CoV-2 infection using data from recipients of many of the vaccines currently being used around the world, as well as from convalescent individuals who have recovered from COVID-19.
In a recent study published in MedRxiv, researchers were able to investigate how waning immunity and antigenic variation might affect vaccine efficacy. Individuals infected with COVID-19 experienced, on average, a two- to five-fold decline in neutralizing antibody titers within six months of recovery. Modeling the decay of neutralization titer over the first 250 days after immunization also highlighted a significant loss in protection from COVID-19 infection. In fact, the decay of neutralizing antibody titers in vaccinated subjects over the first three-to-four months post-vaccination is at least as rapid, and frequently faster than the decline observed in convalescent subjects. Based on their estimates of the level of protection from mild or severe COVID-19 disease associated with a given titer of neutralizing antibodies, we can now predict from this study how changes in immunity will be reflected in clinical outcomes.
Given these significant variables, periodic quantitative testing will lead to a better understanding of the decline in neutralizing antibody titers in both recovered patients and vaccinated individuals. By monitoring antibody levels over time, the healthcare community can more confidently advise on optimal vaccine dosing strategies, which will be a critical driver for the restoration of economies and social interactions.
To validate the accuracy of these new assays, comparisons have been made to the plaque reduction neutralization test (PRNT), which measures virus-specific neutralizing antibody titers and remains the gold standard for serological testing and the determination of immune protection. Based on this comparison, IMMUNO-COV titers correlate well with PRNT titers and therefore provide an excellent alternative to the PRNT assay. But unlike the PRNT, the new assay offers a widely scalable surveillance of COVID-19 protection and vaccine efficacy to meet the enormous global demand.
These results demonstrate the feasibility and utility of neutralization assays for measuring COVID-19 neutralizing antibodies in vaccinated individuals and those recovering from natural infections. With such monitoring, we can better understand what levels of antibodies are required for protection and what booster dosing schedules are needed to sustain vaccine-induced immunity.
Healthcare businesses were hit hard when the pandemic struck. With the rollout of vaccines, we are finding a way out of this tragedy. And now healthcare companies can provide significant safety insight and data, as well as peace of mind, with the new neutralization assay. Hospitals, clinics and private practices will have the information they need to better ensure the safety of their team and make informed decisions for their patients.
About the author:
Dr. Stephen Russell serves as Chief Executive Officer of Imanis Life Sciences, a provider of biotechnology and pharmaceutical products and services in the fields of oncolytic virotherapy and noninvasive reporter gene imaging. Imanis Life Sciences developed and validated IMMUNO-COV™, the first scalable, neutralization assay for COVID-19. A world-renowned researcher in the field of gene and virus therapy, Dr. Russell combines more than three decades of leadership as a clinician and researcher with extensive experience in all aspects of drug discovery and development.