Oral Microbiome Resilience During SARS-CoV-2 Infection and Diversity Shifts After COVID-19 Vaccination in a Hispanic...

The relationship between SARS-CoV-2 infection and the oral microbiome remains poorly understood, particularly in the Hispanic population. Oral samples from 62 individuals (38 SARS-CoV-2 positive, 24 negative) were analyzed using 16S rRNA sequencing, comparing diversity and taxa by infection and symptoms. Longitudinal data from 11 participants assessed microbiome changes as the infection resolved over time. To assess the impact of vaccination, we further examined 68 consistently SARS-CoV-2-negative individuals with paired samples collected before and after vaccination. SARS-CoV-2 infection was not significantly associated with alpha diversity, while beta diversity showed a non-significant but marginal trend (p = 0.051). Prevotella nanceiensis was consistently depleted in infected individuals, even after excluding recent antibiotic users, suggesting a reproducible association with infection status rather than a diagnostic marker. Among infected participants, mucosa-related symptoms were associated with lower Veillonella parvula abundance. Longitudinal data revealed stable microbiome profiles with slightly reduced variance in alpha diversity following viral clearance. In contrast, COVID-19 vaccination in consistently negative individuals was associated with significant increases in Shannon (p = 0.050) and Simpson diversity (p = 0.017), indicating greater evenness without expansion of richness. Beta diversity analyses showed vaccination-related shifts in community composition (PERMANOVA p = 0.026), with increases in Treponema, Campylobacter, Oribacterium, and Selenomonas, and a decrease in Haemophilus. The oral microbiome of Hispanics with mild SARS-CoV-2 infection appeared resilient, with only subtle taxonomic alterations. In contrast, COVID-19 vaccination was associated with short-term increases in diversity and compositional shifts, highlighting its influence on oral microbial ecology.