The study conducted by Souto showed that the distribution of HBV infection in Brazil showed the reduction of hepatitis B prevalence in the country, classifying the national territory as low endemicity to HBV . The present study suggested a pattern of low endemicity, identified by the absence of the HBsAg serological marker .
During home visits, HBV patients were found living in places with difficult access and in precarious conditions, collaborating with the study of El Khouri, who linked hepatitis B infection to poor living conditions .
Study participants were considered at high risk for HBV infection according to behavioral issues, providing them with a sense of invulnerability, which was also perceived by Coutinho in his study on adolescents and hepatitis B vaccine . In the current study, 9% of those examined pointed to lack of interest as the main reason for non-vaccination, although Carneiro et al., cited forgetfulness as the principal reason .
The vaccination booklet was characterized as one of the difficulties during the research, considering that 54.9% of respondents did not have proof of vaccination. One of the ways to solve the problem of losses would be to implement an adequate computerized system with information about vaccines, which is compatible with a study by Santos and Oliveira, where they mentioned the lack of a personalized information system as one of the health system problems .
The absence of HBV carriers among the participants was in accordance with a prevalence study conducted in the state capitals and the Federal District of Brazil. However, it was expected to find in this study a higher percentage of reactive results, considering that the population was composed of individuals subjected to risk situations .
This research identified a rate of 42% (121/288) people with isolated anti-HBs attributed to vaccination, with the highest vaccination coverage of 36.4% in the age group of 1 to 4 years old. When analyzing the population from 0 to 9 years old, 59.6% of anti-HBs isolated reagent was found, inferior to the previous study that found a higher percentage than 70% of vaccinated children from 0 to 10 years old  and also inferior to the study conducted among children and adolescents from Egypt, with complete vaccination scheme that found 57.2% serological protection .
Vaccination coverage in the municipality of Belém was heterogeneous for the period analyzed, and below the national average. This was similar to what happened in a study in the city of Trindade, State of Goiás, which obtained unsatisfactory coverage in most years, considering the basis of hepatitis B prevention is the vaccine, which provides 90–95% protection to immunocompetent individuals, with an appropriate vaccination schedule [16, 17, 18].
The prevalence of 58.3% of non-vaccinated individuals found in the study conducted in Belém was higher than that found in two municipalities of Parauapebas Microregion, southeast of the state of Pará, where, in the municipality of Canaã dos Carajás, the prevalence of 44.1% was detected, and in the municipality of Curionópolis, 36.4% were found susceptible to HBV .
Regarding the age group of children with vaccine delay, the highest prevalence was among children under one year old of age with 66.7%, higher than that found in Carneiro's study that identified 55% for children under the age of six months to one year .