Impact of bariatric surgery on the effectiveness of serological response after COVID-19 vaccination

The primary objective of the current study is to determine whether bariatric surgery reversed the negative impact of obesity on the serological response after the COVID-19 vaccination. This objective is achieved in two steps: (a) quantifying the negative impact of obesity on the serological response after COVID-19 vaccination if it is present, and (b) testing whether bariatric surgery reversed this impact. The secondary objective was to monitor the occurrence of adverse events.

This is a prospective cohort study between May 2021 and August 2021 on the strength of serological response after COVID-19 vaccination. Patients were classified into three groups. Group A (controls with normal or overweight), Group B (bariatric patients pre-operative), and Group C (bariatric patients post-operative). Quantitative antibodies against SARS‑CoV‑2 RBD with a strong neutralizing capacity were quantified from sera after at least 2 weeks post-vaccination.

Of the 276 participants, Group A had n = 73, Group B had n = 126, and Group C had n = 77 patients. Overall, a strongly positive vaccine serological response was observed among 86% in group A, 63% in Group B, and 88% in Group C. Group C showed 5.33 times [95% CI 2.15 to 13.18] higher immune response than group B. Mild to moderate adverse events occurred in 30.1% [95% CI 24.7 to 35.9] of the study samples. Adverse events with the whole virus, mRNA, and vector vaccines occurred in 25%, 28%, and 37%, respectively.

Vaccinating and bariatric surgery are safe and effective treatments in the serological response in patients who suffer from obesity.