Resource IgG4 Antibodies Induced by Repeated Vaccination May Generate Immune Tolerance to the SARS-CoV-2 Spike Protein Ludwig Van - May 30, 2023 0 Vaccines | Free Full-Text | IgG4 Antibodies Induced by Repeated Vaccination May Generate Immune Tolerance to the SARS-CoV-2 Spike Protein (mdpi.com)https://www.mdpi.com/2076-393X/11/5/991