IGHG3 and infection: It has also been postulated that during severe infection withcoronaviruses, a class switch results in the body producing more IgG1and IgG3.[10] Previous studies have reported IgG2 subclass deficiencyin patients with severe influenza (H1N1)[11,12] but there are no studiesto our knowledge that have evaluated IgG subclasses in patientsadmitted with COVID-19 pneumonia.