Alterations in oral microbiome after COVID-19 vaccination and its relationship with vaccine immunogenicity#

Objectives: Microbiomes and immunity were closely related. However, there were few studies on the relationship between oral microbiomes and the immunogenicity of COVID-19 vaccines. Under the background of the continuous mutation of SARS-CoV-2, it was of great significance to study the changes of oral microbiomes after vaccination and their relationship with immunity to improve the body's immunity and enhance the efficacy of vaccines.Methods: A total of 1424 tongue coating samples and blood samples were collected from CoronaVac vaccine recipients before vaccination (V0), 4 weeks after the first dose (V1), and 8 weeks after the second dose (V2) in central China from 2021.01 to 2021.05. Tongue coating samples were subjected to 16S rRNA sequencing, and blood samples were used to detect neutralizing antibody levels and routine biochemical tests. The dynamic change of oral flora and its relationship with neutralizing antibody level during vaccination were analyzed, and a neutralizing antibody prediction model was established based on the random forest model.Results: After the first dose of vaccine, the diversity of the oral microbiota decreased, and the diversity recovery was observed 8 weeks after the second dose. The oral flora of the neutralizing antibody positive population was more sensitive to changes, and the more sensitive the oral flora was, the higher the neutralizing antibody level was. The neutralization antibody prediction model based on the six oral microbial markers also achieved good prediction performance, reaching 76.63% in the training set and 74.19% in the validation set.Conclusions: In conclusion, oral microbiomes and immune response were closely related, and vaccination can affect oral microbiota, and oral microbiota can also affect vaccine immunogenicity. The use of microbial biological interventions may enhance vaccine immunity and establish new oral health management strategies to combat COVID-19.