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Revista Brasileira de Epidemiologia

Print version ISSN 1415-790XOn-line version ISSN 1980-5497

Rev. bras. epidemiol. vol.15 no.2 São Paulo June 2012 



Hepatitis B vaccination and associated factors among dentists



Raquel Conceição FerreiraI; André Luiz Senna GuimarãesII; Rodrigo Dantas PereiraIII; Roberta Maia AndradeII; Renata Pamponet XavierIII; Andréa Maria Eleutério de Barros Lima MartinsII, III

IFaculdade de Odontologia da Universidade Federal de Minas Gerais
IIUniversidade Estadual de Montes Claros
IIIFaculdades Unidas do Norte de Minas





OBJECTIVE: We calculated the prevalence and studied the factors associated with hepatitis B vaccination. Reasons for non-vaccination among dentists were investigated.
METHODS: A cross-sectional study was performed in Montes Claros, Minas Gerais, from 2007 to 2008, to assess hepatitis B vaccination among practicing dental surgeons. Variables were evaluated using a previously tested structured questionnaire. Data underwent descriptive analysis. Non-conditional logistic regression was used to determine the variables associated with hepatitis B vaccination (p < 0.05).
RESULTS: There were 333 subjects eligible for the study, 297 (89.2%) participated, and 283 answered the question about vaccination; of these, 258 (91.2%) completed the three-dose schedule vaccination and 25 (8.8%) were not vaccinated or did not complete the vaccination schedule. Lack of information (48%) was stated as the main reason for not being vaccinated. Variables associated with vaccination were: tobacco use (OR = 2.50; IC95% = 1.22-7.13), alcohol consumption (OR = 2.99; IC95% = 1.16-7.74), satisfaction with the profession (OR = 4.62; IC95% = 1.50-8.25) and knowledge on the post-exposure management protocol (OR = 4.28; IC95% = 1.63-9.26).
CONCLUSIONS: We found a high prevalence of complete vaccination among dentists in Montes Claros. It is higher among professionals who do not use tobacco and alcohol, are more satisfied with their profession and know the protocol after occupational exposure. The study suggests that the lack of information is the main reason for not being vaccinated.

Keywords: Hepatitis B. Vaccination. Occupational Health. Dentist Practice Patterns. Communicable diseases. Dentistry.




The hepatitis B virus (HBV) continues to be a public health problem worldwide, with more than one third of the world population being infected1. The prevalence of HBV infection is higher among dentists than the general population, especially among those who have surgical specialties2-4. The occupational risk of HBV infection through contaminated blood in piercing/cutting accidents among dentists varied between 6% and 30%5,6.

In addition, other body fluids such as saliva and crevicular fluid have the HBV and could be ways of transmission7. The adoption of individual protection measures and the vaccination of workers who come in contact with blood, other body fluids and piercing/cutting instruments or contaminated surfaces are recommended to prevent occupational HBV transmission7.

In Brazil, vaccination against hepatitis B is made available in the primary health care network7 and it must be performed in three doses, in periods of zero, one and six months of interval. Seroconversion must be observed one month after the vaccination schedule is completed and booster doses are not recommended. Individuals who do not respond to the first vaccination schedule must be submitted to new vaccination with three doses8. After three intramuscular vaccine doses, more than 90% of young adults and more than 95% of children and adolescents develop adequate responses to antibodies9.

Complete vaccination was previously reported by 75% of dentists in the city of Montes Claros, a value close to that observed among dentists of other Brazilian cities7,10-13. Length of time working as a dentist and age were factors associated with reported vaccination11. As the debate on the control of infection in universities and of the number of dentists performing in this area becomes more frequent, a higher proportion of vaccinated workers is expected to be found in the present study. The prevalence of vaccination needs to be analyzed throughout time with epidemiological studies, aiming to achieve the ideal situation of 100% vaccination and immunization among Dentistry workers. Additionally, it is important to understand the reasons and factors associated with non-vaccination to guide educational actions. Thus, the prevalence was estimated and the factors associated with complete vaccination against hepatitis B and alleged reasons for non-vaccination among dentists of Monte Claros, MG, were investigated.



An analytical, cross-sectional epidemiological study was conducted in 2007-2008. Dentists registered with the Minas Gerais State Regional Council of Dentistry, City of Montes Claros subsection, who lived in this city and worked in dental clinics or practices, with or without an employment relationship, whether in public or private services, were included in this study. The following individuals were excluded: dentists who did not live in Montes Claros; those who were not performing clinical activities at the moment of this study; and those who were not found after three attempts. All workers were initially contacted by telephone or in person to define study participants.

Data were collected with a previously tested, self-administered semi-structured questionnaire11. Dentists were asked about the practice of vaccination against hepatitis B and the number of doses taken. In the present study, all dentists who completed the primary vaccination schedule with three doses were considered to be vaccinated, whereas those who reported not having been vaccinated or having completed the vaccination schedule (one or two doses) were considered as not vaccinated. The following groups of variables were also analyzed: characterization of dentists with regard to socio-demographic aspects (age group, sex, marital status); lifestyle (tobacco use, alcohol use, physical activity; and personal self-categorization, i.e. how dentists categorize themselves, based on their personal attitudes and behavior: excessively worried, tense and impatient or calm and patient); work-related conditions (length of time working as a dentist, highest title, updating in the last two years, monthly income in minimum wages, breaks during work, piercing/cutting accidents during professional life, hand hygiene before and after consultations, level of satisfaction with the profession, knowledge about the occupational post-exposure protocol); and characterization of the clients cared for (social class, care for patients with a positive HIV diagnosis, and care for patients with a positive HBV or hepatitis C virus - HCV diagnosis). Questionnaires were distributed and subsequently collected in up to eight weeks, in sealed envelopes to maintain participants' privacy.

After a descriptive analysis, factors associated with reported vaccination against hepatitis B were identified with unconditional logistic regression (95% significance level). All variables associated with reported vaccination with a p-value < 0.20 in the bivariate analysis were maintained in the multivariate model. In the bivariate and multivariate analyses, the following variables were dichotomized: marital status, tobacco use, physical activity, length of time working as a dentist, highest title, monthly income in minimum wages, satisfaction with the profession and clients' social class. The SPSS 17.0 (Statistical Package for the Social Sciences 17.0 for Windows) software program was used in these analyses.

The present research project was approved by the Faculdades Unidas do Norte de Minas Research Ethics Committee (FUNORTE 001/06). Authors declared there were no conflicts of interest.



A total of 505 dentists registered with the CRO/MG, city of Montes Claros subsection, were identified, of which 333 were eligible for the present study. Of the 172 excluded, 109 did not perform clinical activities or did so out of the city, 56 were retired and seven were on sick leaves.

A total of 292 dentists (87.7%) participated in this study, with a mean age of 36.9 years (± 9.6; 23 to 68) and a majority of females (52.1%).

There were 283 dentists who answered the question about vaccination, of which 258 (91.2%) had completed the vaccination schedule of three doses and 25 (8.8%) were not vaccinated or did not complete this schedule, due to the following reasons: need for more information (48%), forgetfulness (24%), lack of concern/negligence (8%), fear of vaccination (12%) and lack of vaccine in the health clinic (4%).

In the bivariate analysis, the variables associated with reported vaccination were sex (OR=2.98; 95CI%=1.19-7.43), alcohol use (OR=3.11; 95%CI=1.29-7.46), personal self-categorization (OR=3.86; 95%CI=1.51-9.81), hand hygiene before and after consultations (OR=3.23; 95CI%=1.13-7.83), level of satisfaction with the profession (OR=2.79; 95%CI=1.02-7.83), knowledge about the occupational post-exposure protocol (OR=3.64; 95%CI=1.46-9.04) and care for individuals with a positive HIV diagnosis (OR=2.99; 95%CI=0.99-8.99) (Tables 1 and 2). In the multivariate analysis, the number of reports of complete vaccination was higher among non-smoking dentists (OR=2.50; 95%CI=1.22-7.13), those who did not drink alcohol (OR=2.99; 95%CI=1.16-7.74), those who were satisfied with the profession (OR=4.62; 95%CI=1.50-8.25) and those who were aware of the occupational post-exposure protocol (OR=4.28; 95%CI=1.63-9.26), independently from the remaining variables (Table 3).




Despite vaccination campaigns against hepatitis B, which have been performed among dental students and workers in Brazil since 1995, and the availability of the vaccine in the primary health care network for these workers, there was a group of dentists in the city of Montes Claros who were not vaccinated or did not complete the vaccination schedule of three doses against HBV. However, the percentage of vaccinated dentists was higher in Brazilian studies7,10-15, similar to what was observed among Canadian dentists (90.6%)16, lower than that found among English dentists (97%)17 and higher than those of Japanese (64.3%)18 ; German (74%)19 and Italian dentists (56.2%)20. In Brazil, when the results of studies from the 1990s14,15 and 2000s7,10-15 are compared, an increase in the percentage of vaccinated dentists is observed, varying between 9.29%14 and 34.7%15 among participants of a Congress on Dentistry in 1991 and 1996, and subsequently varying between 73.1% and 82.2%7,10-13in the 2000s. This observation probably shows the positive impact of vaccination campaigns among Brazilian dentists and the increase in adherence to infection control measures.

In the city of Montes Claros, the results of the vaccination against hepatitis B were promising, because the proportion of vaccinated dentists rose from 75% in 2000/200111 to 91.2% in 2007/2008. This increase throughout time is relevant, as vaccination is the most important method to prevent HBV infection21.

Different reasons for non-vaccination have been pointed out in studies and they were also present among dentists of Montes Claros11,19,20. The majority of Italian dentists were not vaccinated against HBV because they believed that vaccination was useless (42.8%) and unsafe (33.3%) and 80.7% stated the need for more information about immunizations20. German dentists also reported that vaccination is not safe (27%), that it is not available (27%), that there is a lack of interest (22%) and that hepatitis B is not a serious disease (17%)19. The main reason for non-vaccination or incomplete vaccination among dentists of Montes Claros was lack of information, as observed in a previous study11. This is surprising, because infection control measures were and still are widely discussed. At times, it seems that such knowledge is ignored by some workers. Similarly, there was a higher number of vaccinated Italian dentists among those who had knowledge about ways of transmission of hepatitis B, who reported not needing additional information and who received information through courses or manuals20. In a previous study, updating courses held in the previous two years increased the chance of dentists being vaccinated11. In the present study, reported vaccination was not associated with updating in the previous two years, although it was higher among dentists who were aware of the occupational post-exposure protocol, who probably had more knowledge about HBV infection prevention as well.

A greater prevalence of vaccination against hepatitis B was found among dentists who did not smoke or drink alcohol. This association was not previously observed3,11,12,20,22, although these variables may refer to care for one's own health. Thus, dentists who do not consume tobacco or alcoholic beverages may be more concerned about their health, like workers who have been vaccinated. However, this hypothesis needs to be further investigated. Satisfaction with the profession influenced the decision to be vaccinated or not, with a higher number of vaccinated dentists among those who responded positively. Dentists who are dissatisfied with their profession may show lack of enthusiasm for it, resulting in negligent behavior and attitudes towards their health and that of their patients. In addition, these dentists seem to neglect the search for new knowledge, which may contribute to non-vaccination.

The previous observation of greater reporting of vaccination among older dentists11,12 with a longer length of time working in this profession3,12 was not found in this study. This finding shows that older cohorts were being replaced by others that had already had access to information about infection control measures, so that such variables could no longer distinguish groups in terms of reported vaccination. These factors probably contributed to the increase in the percentage of vaccinated dentists.

Despite the high prevalence of reported vaccination among dentists, compatible with the values obtained in developed countries, one group remained without vaccination. The present study, unlike the previous ones, showed that individual characteristics associated with professional satisfaction were determinants of the decision of being vaccinated or not. Variables such as age and length of time working as a dentist, previously associated with reported vaccination3,7,11,13,20,22 were not significant in this group, indicating a change in the determinants of vaccination. Thus, in addition to knowledge, workers must be sensitized about the risk of non-vaccination posed to them, their patients and all individuals they live with, seeking a change in attitude. The results of the present study show internal validity, because there was a high response rate. However, these results may be overestimated, as they take workers' reports into consideration, who may choose to give correct responses, even though they do not represent the reality of their practice. Interviewers were trained to reduce bias and they explained the confidentiality of information to participants. As data were collected retrospectively with questionnaires, they were subject to memory bias, which could result in an underestimated prevalence. However, as vaccination against hepatitis B includes three doses, performed on certain dates and controlled on a vaccination card, researchers believe in the validity of results, as workers probably remember this fact. As this was a cross-sectional study, relations of causality could not be investigated, because it was not possible to determine whether exposure was the cause or result of the outcome.

Based on the results of the present study, it could be concluded that there is a high prevalence of vaccination against hepatitis B among dentists of Montes Claros and that this prevalence is higher among non-smokers and those who do not drink alcohol, those who are more satisfied with their profession and those who are aware of the occupational post-exposure protocol. This study suggests that negligent behavior towards one's own health occurs repeatedly. Lack of knowledge is the main reason for non-vaccination. Educational campaigns to fight hepatitis B transmission are necessary, seeking to sensitize health professionals about the importance of vaccination. This theme will be approached together with others that promote self-care and life improvement, including smoking prevention and alcohol use, among others. In addition to preventing HBV infection, vaccination is also aimed at eliminating the group of chronically infected individuals23, which restricts transmission to susceptible individuals, thus contributing to the eradication of this serious infection.



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Raquel Conceição Ferreira
Faculdade de Odontologia da Universidade Federal de Minas Gerais
Departamento de Odontologia Social e Preventiva
Av. Antônio Carlos, 6627 - Pampulha
CEP: 31270-901 - Belo Horizonte, Minas Gerais

Received: 10/13/2010
Final version: 05/13/2011
Approved: 08/08/2011

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