Work

A Decrease of Antibodies Against SARS‐CoV‐2 Antigens Does Not Reflect a Decrease of Neutralization Rate: A Prospective Study to Evaluate Kinetic and Dynamic Humoral Immune Response After Vaccination During Pregnancy

Year: 2025

Type: article

Abstract: PROBLEM: Despite being at increased risk for severe COVID-19, pregnant women were initially excluded from vaccine clinical trials, which limited data regarding vaccine effectiveness and protection in this group. Aiming to better understand the immune response to vaccination during pregnancy, we compared the kinetics and titers of neutralizing and IgG antibodies generated against SARS-CoV-2 during vaccination with BNT162b2 (Pfizer-BioNTech) or CoronaVac (Sinovac Biotech) in a cohort of pregnant women. METHODS OF STUDY: We evaluated participants before vaccination and 30 days after each vaccine dose, using a multiplex bead assay to measure IgG antibodies against SARS-CoV-2 antigens (total spike, spike-1, spike-2, receptor binding domain, and nucleocapsid) and a live virus fluorescence reduction neutralization assay (FRNA) to quantify neutralizing antibodies. RESULTS: Our data showed that vaccination resulted in a robust humoral response, with a considerable increase in the levels of IgG and neutralizing antibodies after the first vaccine dose and a sustained neutralizing response after the vaccine boost. In addition, antispike IgG assays presented a slight decrease after the second dose, while the neutralization rate remained stable. CONCLUSIONS: Immune response to the SARS-CoV-2 vaccine in pregnant women demonstrated an important increase in neutralizing antibodies.

Source: American Journal of Reproductive Immunology

DOI: 10.1111/aji.70053