In addition, due to many mutations from the Wuhan strain in the RBD of the SARS-CoV-2 virus, antibodies from natural infections with subsequent variants, especially Omicron variants from December 2021 onward to completion of the study in May 2022, may not have worked well with this Wuhan RBD spike antigen in the MSD test. The gene discussed is CHMP5; the disease is infection.