IgA, IgM, and IgG Antibodies and Neutralizing Activity against SARS-CoV-2 in a Population of Colombian Healthcare Workers and Hospital Staff

Introduction. During viral infections, the body produces binding antibodies (n-NAbs) and neutralizing antibodies (NAbs). NAbs prevent viral infection of host cells. Since COVID-19's onset in 2020, vaccine research has focused on eliciting high NAb levels. Objective. To evaluate IgA, IgM, and IgG levels in Colombian healthcare workers and compare NAb test results from DIA.PRO and CPAS. Method. A cross-sectional study in Bucaramanga, Colombia, collected samples from healthcare workers in June-July and November 2021. Data was gathered via an online survey and blood samples. Antibody levels were measured with AESKULISA® kits, and neutralizing activity was assessed using DIA.PRO and cPass kits. Statistical analyses used Wilcoxon tests and Pearson correlation. Results. Eighty participants were initially assessed, with forty-seven re-evaluated. Most were women who had received the BioNTech-Pfizer vaccine. Antibody levels declined over time; IgA and IgM were lower in the second sampling, while IgG remained high. Prior COVID-19 infection correlated with higher antibody levels. DIA.PRO and CPAS tests showed strong agreement, with excellent neutralizing reactivity in most participants. Conclusion. Neutralizing antibody levels against SARS-CoV-2 decrease but remain effective in most healthcare workers, supporting BNT162b2 vaccine efficacy. Further research is needed on emerging variants and neutralizing antibodies in COVID-19 management.