COVID-19 Immunity Passports?

As the COVID-19 persists, the numbers of infected continue to rise at alarming rates. As I have been watching the news channels to keep myself updated on these numbers, I have also stumbled upon the plummeting stock markets. The United States has implemented stimulus acts and other countries have attempted to fight their economies from crumbling. All while still trying to keep the healthy population steady and death toll as low as possible. Though as stay-at-home measures in the United States continue given the later hit of COVID-19, other countries are pondering the possibility of ‘Immunity Passports’.

Countries that are considering Immunity Passports include Germany and the UK at large. The main idea of these passports is to get people out of their homes, back to work and begin to fall back into normal routines–but ONLY if you are claimed immune to COVID-19. And how do these countries decide who is immune and who is not? At home antibody testing. Simply through a prick of a finger for a blood sample and an apparatus for testing such sample.

Via MIT Technology Review journal, the antibodies that these tests look for are IgM, IgG and IgA. These antibodies are particularly important because after an individual has been exposed to the virus, the proteins specific to SARS-CoV-2 virus are able to be recognized (or bound) to the naive mature B cells or plasma cells. Once recognized, the SARS-CoV-2 viral proteins trigger the proper/specific immune response to fight off the virus. The creation of these antibodies determine how their bodies will react to COVID-19 both initially and if reinfected. But the big question is; why are these antibodies so important and worth being tested for?

Without getting into too much ~scientific~ explanation as my family likes to claim I do (but will probably fail), our immune system response begins with a specific antigen entering the body. In terms of COVID-19, our antigen is presented from viral SARS-CoV-2. Dendritic cells become activated via pathogen recognition receptors (PRRs), binding to MAMPS, DAMPS or PAMPS to allow dendritic cells to know the specific immune response to trigger with presentation of SARS-CoV-2. Dendritic cells down-regulate self peptides and up-regulate pathogen peptides on their MHC Class I and II molecules, triggering the right T cells through simultaneous signals to become ready-to-fight effector T cells (helper or cytotoxic). Though while this is also happening, the same antigen finds a B cell that is specific to the same response. Cross linking of at least two B cell receptors (BCR) occurs, exogenous antigens are placed into its MHC Class II molecules to up-regulate B7, CD40 and cytokines (signal one). Finally IgM is secreted and causes a short-lived antibody production to fight the virus. An individual with only IgM antibody titers will only be “immune” (using this term lightly) for up to 10 days.

In order for longer acting IgG and IgA antibodies to be secreted from the B cell, a second signal from a fully activated T helper cell must occur. Expression of both IgM and IgG antibody titers can provide a much longer protection against COVID-19 (up to 21 days). Though the most effective antibodies would be mainly IgG secreted from plasma cells or memory B cells, which can provide long term immunity against COVID-19. This is why specifically individuals presenting IgG antibody secretion would be targeted to be granted Immunity Passports.

Though sadly there are drawbacks to this testing that weight on scientist’s consciouses. The possibility of false immune positives from the tests limited capabilities (i.e. sensitivity vs. specificity) and that those who are truly ‘positive’ with primarily an IgG antibody titer can still possibly infect others. Even with so symptoms, aka asymptomatic. A recent study reveals that SARS-CoV-2 infections have been found to have different stages. With specifically stage I, “stealth” carriers, being hard to control with shedding the virus unknowingly. Along with even some discharged patients showing returning SARS-COV-2 positive and even relapsing.

Overall, it is understandable that all across the world people are trying anything to safely return to normal life. Though they continue to struggle on what protocols are safe enough to avoid stronger waves of the COVID-19 pandemic.