COVID-19 Antibody Response

It’s on everyone’s mind and I’m sure we’re all sick of hearing about it every time we partake in any sort of media, but COVID-19 is ravaging the world. But how exactly does this enigmatic disease work? Who is at risk of being infected, and can they be infected twice? Well the answer to those questions involve antibodies. Antibodies are like little troops that serve numerous functions in the immune system, from tagging a pathogen for phagocytosis to binding to the pathogen to preventing its movement. There are several different types of antibodies, all of which serve different functions and mean different things when it comes to COVID-19 testing.

One way that antibodies can prevent an infection is through neutralization. Neutralization is when the antibodies bind to sites on a virus or toxin to prevent their interaction with their target cells. This article from Scientific American discusses that neutralization antibodies would be the most effective way to devise a treatment for COVID-19, because if the human body naturally produces neutralizing antibodies against COVID-19, all we have to do is find what site on the virus they bind to in order to devise a treatment that mimics their action.

So what does the COVID-19 antibody response look like, and how can we use that to test for the disease? This article from the NCBI describes which antibodies are produced at which points in the infection, which can be useful in determining what stage of infection the person is in. The article describes the antibody IgM being most prevalent due to the primary response in the early stages of the disease, followed by production of the antibody IgG around week 2 in the secondary response. IgG then sticks around for about two years in other SARS-CoV virus infections, so it is likely that this could be the case with COVID-19 as well. So what does this mean for testing? If a person is tested and only IgM is present, it means this person is likely in the early stages of infection and should be quarantined immediately in order to prevent spread, as they may not be symptomatic yet. If both IgM AND IgG are present, it likely means they have been infected for a while, and should be quarantined for safety. If they only show IgG, it’s likely that they were infected at one point and overcame the infection, and are no longer infectious and hopefully unable to contract COVID-19 again.

Clearly, antibodies are extremely useful bits of the immune system that mean a lot. They can prevent infection from diseases like COVID-19, and it’s imperative that the antibody response start quickly in order to lessen the disease’s effects. In the NCBI article, it’s discussed how other SARS-CoV cases that have a delayed antibody response have a more severe outcome. Antibodies are also useful in determining who is safe to go out without fear of spreading COVID-19, which is super important in this moment as we try to flatten the curve to prevent from overwhelming our healthcare services. This is why universal testing needs to be made available, so we can see who has been exposed, who is infected, and who can’t contract the virus anymore. This would help get society opened back up as quickly as possible with the fewest restrictions, getting everything back to normal.