Coronavirus Titer Fighters

As the economic and social shutdown in the United States continues to drag on, the general public has been more and more eager to know when everything will return to normal. Yet, such a thing is hard to predict when many of the coronavirus drugs and vaccines are still under production, and our current knowledge of the spread of the virus comes from estimates that don’t factor in the unknown populations of untested patients. With unemployment rising to record levels, and an overwhelming amount of small businesses closed for the time being, it makes one wonder just how long our country can last in this standstill. Understandably, the government also wishes for as many people to return work as soon as possible, but it is paramount to prevent the further spread of the virus and ensure safety in doing so. It is therefore important to identify individuals who have immunity to the virus (and are therefore safe to return to the public) and those who still have virus in their bodies.

This is most easily done through antibody titers, which are measurements of bloodstream antibodies, one of the immune system’s soldiers that target specific pathogens. When these titers are taken from blood serum samples, they are known as serology tests. The tests can reveal the status of the immune response to coronavirus, which would be useful in determining who can re-enter the workforce safely. For example, a pure IgM titer can indicate infection early on in a patient who has never been infected before, and an IgG titer can indicate how likely one is to be immune to future infections (a positive IgG titer would imply that the individual has encountered Covid-19 and developed a strong response to and future protection against it). A combination of IgM and IgG titer can be used to track the overall progression of the immune response. Yet, a New York Times article reporting on such tests notes that the serology tests are not a one-stop ticket to release from quarantine. Some patients may have less effective antibodies, while others show immunity despite having low antibody levels.

However, it is encouraging to see the amount of effort being put forth to tackle the monumental issue of Covid-19 testing. The CDC and WHO are mounting projects to tackle mass testing, and researchers are investigating more robust tests that decrease false positives and false negatives. There are still many unknowns to tackle though; a recent paper investigating Covid-19 titers of recovered patients found a wide variety of antibody levels in these individuals – suggesting that other immune factors may be involved and that antibody testing alone is insufficient to declare immunity. It is also unknown whether immunity lasts forever, or if reinfection is a concern. Although much more research is needed on how exactly the virus attacks and how our body responds, the emergence of novel titers in the fight against Covid-19 gives us new hope in an otherwise bleak landscape.