A functional diagnostic using clinically-relevant cell-based and cell-free assays to predict adequate protective immunity against COVID-19
Since the SARS and MERS outbreak in 2002 and 2012 respectively, repeated efforts to produce a successful vaccine have failed. Several previously attempted vaccines failed in animal studies for the following reasons:
A. Insufficient antibody response.
B. Lack of developing a cell-mediated immunity.
C. Antibody development enhancement.
Since the outbreak of SARS-COV-2 (COVID-19) there are now over 100 vaccine candidates in development. Yet, there is only a 5 percent chance that any particular vaccine will be safe and effective. There is a concern that several vaccines are being rushed into clinical trials without prior preclinical animal studies. There are estimates that a vaccine will be available in 12-18 months. Yet, it's not clear what level of neutralizing antibodies from vaccines will provide protection. It's not clear what level of neutralizing antibodies from recovered patients will provide protection.
There are limitations in diagnostics that measure serological antibody levels to COVID-19. Quantifying blood levels may lack functional relevance. Antibodies to COVID-19 may differer between patients that recover from the infection and those that are vaccinated due to glycosylation or post-translational modification (PTM) of viral proteins. It is difficult to predict whether the presence of antibodies from vaccines can offer protective immunity.
There are fundamental questions in determining whether a vaccine can provide effective immunity.
A. Does a vaccine produce the same glycosylated antibody against the viral immunogen as when a patient who recovers from COVID-19?
B. Does the antibody produced from a vaccine neutralize the immunogen as well as when a patient recovers from COVID-19?
C. Does the patient's antibody level protect against COVID-19 attachment to alveolar epithelial cells?
D. Does the patient's antibody level prevent COVID-19 from causing alveolar cell injury?
E. What is the minimum plasma antibody level that inhibits COVID-19 cell attachment and alveolar cell injury from natural immunity and is that level similar for vaccines?
F. What is the minimum plasma antibody level that mediates antigen-antibody neutralization from natural immunity and is it the same for vaccines?