Probiotic Supplementations Preserve Protective Immunity Against SARS-CoV-2 Spike Protein After a Triple Combination of COVID-19 Vaccination

Abstract

Introduction: Immunoglobulin G against SARS-CoV-2 spike protein declines over-time in vaccinated individuals. Trend to restore protective immunity is challenging.

Objectives: Probiotics have beneficial effects to human innate and adaptive immune responses. This study aimed to compare immune preservation of probiotic supplement versus placebo by measuring the mean and percent reduction of COVID-19 antibody level among those subjects receiving a triple dose combination of COVID-19 vaccine.

Methods: A randomized, double-blinded, placebo-controlled trial, conducted in Bangkok-Samui hospital between December 2021 to February 2022. There were 30 volunteers, divided randomly into 2 groups. The target group received probiotics supplement once daily for 6 weeks, while the control group received placebo. Blood testing for SARS-CoV-2 spike protein Immunoglobulin G level was collected at day baseline and week-6 visit. Data were analyzed by Statistical software with Statistical Package for the Social Sciences (SPSS) version 23.0, including descriptive and analytical statistics.

Results: The mean of SARS-CoV-2 spike protein IgG antibody level between probiotic and placebo group at the baseline was not difference (P = .4178). Subjects received probiotic supplement for 6 weeks found SARS-CoV-2 spike protein IgG antibody level reduction significantly (P = .003). The control group also found antibody level reduction significantly (P < .001). The Probiotic group found a significantly lower percent reduction of SARS-CoV-2 spike protein IgG antibody at week-6 visit from the baseline than the placebo group (35.7% vs. 48.3%, respectively, P = .007). There is no adverse event at the end of this study.

Conclusions: Taking probiotics supplement once daily for 6 weeks could preserve immunity level with less percent reduction than the placebo, with no adverse effect occurred.