Many COVID-19 infections are mild or with unclear symptoms, so not everyone will be tested for the actual presence of the virus. But, most people produce immunoglobulins (alias: antibodies) against the viruses. Whether the immunoglobulins formed have a protective function against COVID-19 is currently still controversial, but immunologically probable.
From about 5-8 days after infection, our immune system produces so-called immunoglobulins to defend against viruses. While immunoglobulins M (IgM) are only present until about week 6 after infection (short-term parameters), immunoglobulins G (IgG) can be measured much longer (long-term parameters).
In our rapid test you will have an answer after 15 minutes whether you have ever could have had a COVID-19 infection, or whether your COVID-vaccine already works. If you are interested, it is better to test after the second vaccine shot.