By devaluing the serological test we throw the baby out with the dirty water

According to a quite diffuse opinion, also amplified by the media, the serologic test has a limited diagnostic value and is of no use as an indication to the booster dose of a COVID-19 vaccine. In addition, this point of view was strengthened by a hasting criticism, which appeared in television, social networks and newspapers and was based on a personal interpretation of a paper published in NEJM Oct 2021. The current article shows how the NEJM paper asserts just the opposite thesis, supporting the serologic test instead. Details are here provided, especially about the effective antibody/infectivity correlation and the possible threshold value between diseased and healthy people. The conclusion is that the NEJM paper strongly supports the serologic test, while the quick criticism derived from a biased lecture, in search of the confirmation of a preconception.