What is the difference between IgM, IgG and IgA antibodies?

There are three different antibodies that can be tested in connection with the novel coronavirus – namely IgG, IgM and IgA antibodies.

IgM and IgA antibodies are produced by the body at the beginning of an acute infection to fight it. However, they only remain in the body for a few days or weeks, which is why a test for IgM antibodies can only indicate an acute infection.

IgG antibodies, on the other hand, are produced at a slightly later time as an immune response to an illness, to protect the body in the future if it comes into contact with the virus again. They can therefore be an indicator of existing vaccination protection or past Covid-19 infection.