An article in the Minneapolis paper today discussed the looming availability of an antibody test for coronavirus, developed by the University of Minnesota and the Mayo Clinic. I assume a number of other research and commercial institutions are working on or have such tests. We need to immediately initiate a widespread, free-to-the-public program of such testing. This is as important as testing for coronavirus infection. These antibody tests examine a person’s blood and if antibodies to the current strain of coronavirus are present, that would indicate that the person was infected and has recovered and is likely virus free, even if they were asymptomatic during the infection period.
The tests should be used first for all health care workers, first responders and others who have frequent contact with the public, like grocery store employees. Those who have antibodies would know they are safe from infection (some early reports of re-infection appear to instead have been due to incomplete clearing of the virus and resurgence of it) and could go about their jobs without fear of either being infected or passing on an infection to others. (There may be a period of time when a person both still has some virus and antibodies, so a negative infection test would also be appropriate.) Those in these groups who don’t have antibodies, would know they may still be at risk for infection and should be extra cautious, given their level of potential exposure. (This group presumably has had an infection test to ensure that they aren’t infected but asymptomatic and therefor at risk for spreading the disease to others.)
But at the same time, there should be some randomized screenings of the population, or as one Colorado town is apparently doing, (Colo. Test) test a whole localized population. A more geographically widespread test would be more informative, but either method would give us better data on what percent of a population has been infected and now is cleared and has antibodies to further infection. This would help explain the mystery of why a large percentage of the population appears to not get infected even after exposure to the virus. But most importantly, it would allow us to identify people who would be immediately permitted to resume normal activities, go to work, go wherever they want in public, and so on. These people would presumably carry their test results with them to demonstrate their antibody status. (or we can just put a big A for antibody on their foreheads)
I don’t know quickly the volume of testing could be ramped up, but as much effort should be put into this as into infection testing. Some uncertainties to me are what the false positive and false negative rate might be; how frequently we might need to retest people who initially test negative for antibodies and whether the tests would pick up coronavirus antibodies other than those specific to this strain. This last item would be useful to know, because one obvious reason for the low infection rate would be the presence of generalized coronavirus antibodies that work against this strain. If that isn’t the explanation for the low infection rate, we would need to identify what other protective factors are at work, and how persistent that protection might be. It may also be that this protective factor could be exploited as a preventive measure. Finally, at some point we need to have studies designed to identify how long the antibodies to this coronavirus strain can be expected to last. Some research has suggested that general coronavirus antibodies aren’t particularly strong or long-lasting, because typically the disease caused isn’t very severe.