Contributed Commentary by Priya Nanavati and Douglas Lake
August 2, 2021 | As more people become vaccinated, researchers are continuing to evaluate the duration of immunity and variations in an immune response among previously infected and non-infected people, using neutralizing antibodies as their metric. This growing body of information presents critical data about COVID-19 immunity that determines when and how individuals should protect themselves from the virus. Understanding immunity levels offers global solutions for ending the COVID-19 pandemic and addressing future health crises.
Unpacking Neutralizing Antibodies: Natural Boosting and the Risks of Infection
The objective of a COVID-19 vaccine is to induce virus-neutralizing antibodies. Neutralizing antibodies differ from other types of antibodies because they physically block the virus from infecting host cells. Neutralizing antibodies are foundational to the fields of vaccinology and viral immunology.
COVID-19 vaccines have been shown to be highly effective in reducing clinical illness, hospitalizations, and COVID-19 related deaths. However, the longevity of antibody-based protective immunity is not yet known and likely differs for everyone. Recent studies indicate protective antibodies can still be measured six months after vaccination, but it is unclear what levels will protect against the virus. While the CDC’s updated guidance to lift the mask-wearing mandate marks significant progress in overcoming the pandemic, as vaccinated individuals de-mask, some will be at higher risk of infection because their neutralizing antibodies have declined below the level at which they can protect against infection.
Scientists have observed with other viruses that natural boosting continually induces high levels of neutralizing antibodies. Natural boosters occur when an individual who has been vaccinated or recovered from infection is infected by another individual spreading the virus. The vaccinated or recovered individual is not likely to become clinically ill because their immune system remembers the recent infection and reactivates immune memory including B cells that produce neutralizing antibodies. This re-exposure and boosting phenomenon may happen dozens of times as a virus moves through a population.
However, since COVID-19 replicates faster than immune memory, it is not yet clear if a recovered or previously vaccinated individual can transmit the virus while their immune memory re-builds protective levels of neutralizing antibodies again. It is during this time that individuals with low levels of neutralizing antibodies, regardless of their vaccination status, may unknowingly transmit the virus to others.
Testing is the Tool to Understand Immunity
To understand our ever-changing neutralizing antibody levels and determine whether we are at risk for contracting COVID-19, we should regularly conduct consistent, accurate neutralizing antibody testing to monitor levels of protective neutralizing antibodies. Many rapid tests simply detect the presence or absence of antibodies against nucleocapsid or spike proteins, but only a few measure levels of functional neutralizing antibodies. (We have worked together to develop a test that does measure functional neutralizing antibodies.) Individuals’ understanding how neutralizing antibodies work and evolve in the body, through continuous testing, is more critical now than ever as public health precautions like mask mandates are reduced.
Neutralizing Antibodies are Critical for Guiding Us Out of the Pandemic
Research about neutralizing antibodies offers many use cases for protecting against COVID-19 worldwide, and rapid testing offers insight into COVID-19 vaccine efficacy and longevity. Companies can leverage frequent and consistent neutralizing antibody tests to develop corporate surveillance programs. When combined with rapid antigen testing, these programs enable employees to understand their level of protection against COVID-19 and corporations can prevent potential outbreaks, keeping their businesses open.
Continued research and newfound familiarity with neutralizing antibodies offer a powerful tool to manage, treat and prevent other viruses and global pandemics down the line. Regulatory bodies responsible for approving tests and vaccines are now better equipped to rapidly authorize treatments and tests using lessons learned from the COVID-19 pandemic.
Most importantly, regular testing for protective levels of neutralizing antibodies empowers people to make informed decisions about their own health. It also encourages personal responsibility and the ability to keep communities safe and healthy.
Priya Nanavati, PhD, is the Managing Director of Production and Research and Development at Empowered Diagnostics. She has deep experience across scientific research and product development. Priya oversees all research, clinical trials and testing optimization and validation at Empowered Diagnostics. In addition, she heads up the team of scientists and production managers that develop and manufacture Empowered Diagnostics’ lateral flow assays. Priya holds a bachelor’s degree in Biochemistry, a master’s degree in Human Genetics, and a PhD in Biomedical Science. She can be reached at priyan@empdx.net.
Douglas Lake, PhD, is a molecular and cellular immunologist at Arizona State University and a co-founder of Sapphire Biotech. In partnership with Empowered Diagnostics, Mayo Clinic and Arizona State University, Dr. Lake has developed the science behind the ImmunoPass COVID-19 Neutralizing Antibody Rapid Test. Dr. Lake’s laboratory focuses on tumor immunology and related therapeutics. Dr. Lake is an associate professor at Arizona State University in the School of Life Sciences with an adjunct appointment at Mayo Clinic. He can be reached at douglas.lake@asu.edu.