Background: Viral hepatitis is a disease that is more prevalent among individuals residing in remote regions and in contexts of social vulnerability. The objective of this study was to ascertain the seroprevalence of hepatitis A (HAV), B (HBV), and C (HCV) in vulnerable communities in the rural area of São João do Piauí (SJP), northern Brazil. Methods: Immunoenzymatic assays were employed to detect the presence of anti-HAV (total and IgM), HBsAg, anti-HBc, anti-HBs, and anti-HCV serological markers in serum samples. Samples that yielded positive results were subjected to further analysis using real-time polymerase chain reaction (PCR). Results: A total of 492 individuals, ranging in age from 3 to 101 years, were consecutively recruited from eight rural communities. The majority of individuals were female (51.2%), over 30 years of age (57.1%), self-identified as Black/Brown (92.2%), and resided in Afro-Brazilian communities, designated as “quilombos” (68.1%). The seroprevalence of anti-HAV was 69.5% (95% CI: 65.4–73.6%), while that of anti-HBc was 4.7% (95% CI: 2.8–6.6%), and that of anti-HBs was 35.2% (95% CI: 30.1–39.4%), and 0.2% (95% CI:0.0–0.6%) for anti-HCV. Conclusions: The seroprevalence rates observed were higher than the national average, and a significant proportion of individuals in the target age groups were susceptible to HBV, despite the availability of vaccination. These findings highlight potential shortcomings in the management of vaccine-preventable diseases, which could have implications for public health.
