A group from NMI Natural and Medical Sciences Institute at the University of Tübingen, etc. has reported on the cross-reactivity of hCoV-specific IgGs against SARS-CoV-2 infected and uninfected individuals using 1,173 serum/plasma samples.
https://www.nature.com/articles/s41467-021-20973-3.pdf
Up to now, it has been known that there are 4 kinds of epidemic human coronaviruses (hCoVs: NL63, 229E, OC43, HKU1) which cause seasonal colds.
As shown below, there is certainly correlation between SARS-CoV-2 and hCoVs specific IgGs to a certain degree. 10% of SARS-CoV-2 infected individuals do not develop detectable SARS-CoV-2-specific IgG, but it has not been identified if this result could come from cross-reactivity of hCoVs-specific IgGs or just from innate immunity against SARS-CoV-2.
