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HEPATITIS B IN RONDÔNIA (WESTERN AMAZON REGION, BRAZIL): descriptive analysis and spatial distribution

Hepatite B em Rondônia (região da Amazônia Ocidental, Brasil): análise descritiva e distribuição espacial

Abstracts

Background

The Amazon is one of the regions who have the highest rates of infection by the hepatitis B virus in the world.

Objectives

This study aimed to evaluate the epidemiological data and spatial distribution of hepatitis B cases reported between 2002 and 2012 in the Brazilian State of Rondônia.

Methods

Social and clinical data of these individuals were studied through the Information System for Notifiable Diseases (SINAN), including the following variables: gender, age group, vaccination, contact with a known patient with HBV, exposure to risk factors, source of infection, and clinical status.

Results

There were 7,132 cases reported in Rondônia, with an average incidence rate of 42/100,000 inhabitants per year. The municipalities with the highest incidence rates were Monte Negro (187.6/100,000 inhabitants) and Ariquemes (157.2/100,000 inhabitants). The 20-39 year-old age group had the highest number of cases (n = 3,834), and 69.9% of patients were likely infected via sexual contact. Regarding the clinical disease status, most of the patients (80.7%) were in the chronic phase.

Conclusions

There was a recent 402% increase in the diagnosis of hepatitis B, which is likely owing to the improvements in the public diagnostic system. This highlights the need for public policies to prevent and control the disease.

Hepatitis B; Epidemiology; Hepadnaviridae ; Sexually transmitted diseases


Contexto

A Amazônia é uma das regiões que possui as maiores taxas de infecção pelo vírus da hepatite B do mundo.

Objetivos

Esse estudo teve como objetivo avaliar dados epidemiológicos e a distribuição espacial dos casos de hepatite B notificados no Estado de Rondônia no período de 2002 a 2012.

Métodos

Foram estudados dados clínicos e sociais desses indivíduos através do Sistema de Informação de Agravos de Notificação (SINAN). Foram analisadas as seguintes variáveis: gênero, faixa etária, vacinação, contato com paciente sabidamente portador do vírus hepatite B, exposição do paciente aos fatores de risco, fonte de infecção e forma clínica.

Resultados

Foram notificados 7.132 casos, tendo uma incidência de 42/100.000 habitantes por ano. Os municípios que apresentaram as maiores taxas de incidência foram Monte Negro, 187,6/100.000 habitantes e Ariquemes, 157,2/100.000 habitantes. A faixa etária com maior número de casos foi de 20-39 anos (n=3.834), sendo que 69,9% dos pacientes se infectaram provavelmente por via sexual. Em relação à forma clínica da doença, a maioria dos pacientes (80,7%) se encontra na fase crônica.

Conclusão

Houve um aumento do diagnóstico do vírus da hepatite B da ordem de 402% nos últimos anos, seguramente pela melhora no sistema de diagnóstico da doença, sendo necessário uma maior atenção das políticas públicas de prevenção e controle da doença em função de sua elevada prevalência.

Hepatite B; Epidemiologia; Hepadnaviridae ; Doenças sexualmente transmissíveis


INTRODUCTION

Infection with hepatitis B virus (HBV) is a global phenomenon, with approximately 360 million chronic carriers of the virus. More than a million infected individuals die every year due to complications of hepatitis( 22. Barros Júnior GM, Braga WSM, Oliveira CMC, Castilho MC, Araújo JR. Hepatite crônica B oculta: prevalência e aspectos clínicos em população de ele­vada endemicidade de infecção pelo vírus da hepatite B na Amazônia ocidental brasileira. Rev Soc Bras Med Trop. 2008;46:596-601. ). In Brazil, the disease is considered an important public health problem, with the presence of endemic areas in the Northern region and some micro-regions of the States of Paraná, Espírito Santo, and Mato Grosso( 22. Barros Júnior GM, Braga WSM, Oliveira CMC, Castilho MC, Araújo JR. Hepatite crônica B oculta: prevalência e aspectos clínicos em população de ele­vada endemicidade de infecção pelo vírus da hepatite B na Amazônia ocidental brasileira. Rev Soc Bras Med Trop. 2008;46:596-601. ). In the Amazon region, 5%-15% of the population are chronic carriers of the virus, representing one of the highest incidences in the world( 1212. Oberle MW, Shapiro CN, Lanier AP. Preventing hepatitis B in people in close contact with hepatocellular carcinoma patients. Public Health Rep. 1997;112:63-5. ). Specifically, the high endemicity observed in Rondônia, which is a State in the Amazon, may be related to failures in the prenatal program, unprotected sexual activity, absence of sterilization of equipment (dental, manicure, and tattoo), and poor control of blood used in transfusions( 88. Lobato C, Tavares-Neto J, Rios-Leite M, Trepo C, Vityitski L, Parvaz P, et al. Intrafamilial prevalence of hepatitis B virus in Western Brazilian Amazon region: epidemiologic and biomolecular study. J Gastroenterol Hepatol. 2006;21(5):863-8. , 1414. Vieira GD, Ventura CG, Sousa CM. Occurrence and spatial distribution of hepatitis C in a western Brazilian Amazon State. Arq Gastroenterol. 2014;51(4);316-9. ).

The virus has a high infectivity and is 57 times more infectious than the human immunodeficiency virus (HIV)( 1111. Ministério da Saúde. (Brasil). Secretaria de Vigilância em Saúde. Departamento de DST, Aids e Hepatites Virais. Boletim Epidemiológico: hepatites Virais. Brasília: Ministério da Saúde; 2012. ). Currently, health professionals, patients on hemodialysis, sex workers, and newborns of mothers with HBV are considered those most at risk. HBV infection is underreported owing to the broad spectrum of clinical characteristics at presentation and the insidious progression; these characteristics also result in increasing spread of the disease. Thus, given the highly endemic Northern region, the disease is of epidemiological importance( 99. Luna EJA, Moraes JC, Silveira L, Salinas HSN. Eficácia e segurança da vacina brasileira contra hepatite B em recém-nascidos. Rev Saúde Pública. 2009;43:1014-20. ). This study aimed to delineate the epidemiology and spatial distribution of hepatitis B in the State of Rondônia during 2002-2012 using data from the Information System of Notifiable Diseases (SINAN/DATASUS).

METHODS

This is an observational and descriptive study of notified cases of hepatitis B in the State of Rondônia between 2002 and 2012. Data from the Information System of Notifiable Diseases, SinanNET and SinanW, were analyzed. The program TABWIN (www.datasus.gov.br/tabwin) was used to generate the maps. The following variables were collected and analyzed: gender, age group, vaccines, contact with a known carrier of HBV, exposure to risk factors, source of infection, and clinical status.

RESULTS

During the study period, 7,132 cases aged 0-96 years were reported, resulting in an average 648.2 cases per year. The average total incidence was 42/100,000 inhabitants, and the incidence progressively increased from 2002 to 2011 (Figure 1).

FIGURE 1.
Exponential trend and incidence of diagnosed cases of hepatitis B in the State of Rondônia during the period 2002-2012

Source: SINANW and SINAN NET


The municipalities with the highest incidence rates were Monte Negro (187.6/100,000 inhabitants), Ariquemes (175.2/100,000 inhabitants), and Vilhena (136.2/100,000 inhabitants) (Figure 2). Regarding gender, 3,443 cases (48.2%) were men. The highest prevalence occurred in the 20-39 year-old age group (3,834, 53.8%). The full scheme of the vaccine was received by 1,681 (27.8%) patients with HBV. One hundred and twenty-one (1.7%) patients had concomitant HIV infection. Eight hundred and two (11.2%) patients had sexual contact with a known carrier of hepatitis B. The main source of infection was sexual contact for 1,967 (69.9%) patients (Table 1).

FIGURE 2.
Incidence of hepatitis B cases in the State of Rondônia during the period 2002-2012

Source: SINANW and SINAN NET


TABLE 1.
Social and clinical data of patients with hepatitis B in Rondônia during 2002-2012

DISCUSSION

The Amazon region has high rates of HBV infection( 99. Luna EJA, Moraes JC, Silveira L, Salinas HSN. Eficácia e segurança da vacina brasileira contra hepatite B em recém-nascidos. Rev Saúde Pública. 2009;43:1014-20. ), as supported by the results of the present study; the average incidence in the State of Rondônia was 42/100,000 inhabitants, and 9 of the 52 municipalities had an incidence >40/100,000 inhabitants, indicating a high endemicity. These municipalities were primarily located in the West and South of the State. According to the Ministry of Health( 1111. Ministério da Saúde. (Brasil). Secretaria de Vigilância em Saúde. Departamento de DST, Aids e Hepatites Virais. Boletim Epidemiológico: hepatites Virais. Brasília: Ministério da Saúde; 2012. ), the average incidence in Brazil was 6.5/100,000 inhabitants during the period 2005-2010, while the North region had an incidence of 11/100,000 inhabitants in 2010. A larger proportion of the population in Rondônia has access to diagnostic and treatment services, which promotes not only greater control but also a higher reported incidence, such as in the municipalities of Monte Negro (187.6/100,000 inhabitants) and Ariquemes (175.2/100,000 inhabitants), where there are a blood center and hemo nucleus, respectively( 44. Camargo LMA, Moura MM, Engracia V, Pagotto RC, Basano SA, Silva LH, et al. A rural community in a Brazilian Western Amazonian Region: Some demographic and epidemiological patterns. Mem Inst Oswaldo Cruz 2002;97(2):193-5. ).

Most of the patients with HBV in the present study were aged 20-39 years, similar to the findings by Cruz et al.( 77. Cruz CR, Shirassu MM, Martins WP. [Comparison between hepatitis B and C epidemiological profiles at a public institution in São Paulo, Brazil]. Arq Gastroenterol. 2009;46:225-229. ), where 48.6% of the patients were also in this age group. This age range is considered to include sexually active individuals; therefore, preventive measures are required in this age group to prevent sexual transmission of the disease( 77. Cruz CR, Shirassu MM, Martins WP. [Comparison between hepatitis B and C epidemiological profiles at a public institution in São Paulo, Brazil]. Arq Gastroenterol. 2009;46:225-229. ).

Since 2000, the hepatitis B vaccine is mandatory for all newborns and individuals aged up to 49 years, to ensure immunological protection for at least 20 years. However, despite mandatory vaccination, there are several barriers to achieving vaccination of the entire target population, including fears of adverse reactions, absence of information about the transmission of the virus and risk of infection, lack of time due work, and difficulty accessing immunization( 11. Assunção AA, Araújo TMA, Ribeiro RBN, Oliveira SVS. Vacinação contra hepatite B e exposição ocupacional no setor saúde em Belo Horizonte, MG. Rev Saúde Pública. 2012;46:665-73. , 1010. Ministério da Saúde. (Brasil). Fundação Nacional de saúde. Programa Nacional de Imunização: PNI 25 anos: Brasília, MS, 1998. ). In Rondônia, 61.3% of individuals who acquired the virus had not been vaccinated; in addition to the factors already mentioned, there was a period of time when adults were not vaccinated, which may explain this high proportion of people who were not vaccinated in the present study. At the same time, according to Chávez et al.( 66. Chávez JH, Campana SG, Haas P. Panorama da hepatite B no Brasil e no Estado de Santa Catarina. Rev Panam Salud Pública. 2003;14:91-6. ), 95% of individuals vaccinated against hepatitis B develop adequate levels of antibodies; in other words, the vaccine is effective for 95% of people, while the remaining 5% remains resistant to antigens or requires additional doses of the vaccine to be sensitized. In the present study, 27.8% of individuals infected with HBV had been properly vaccinated. These individuals may not have achieved seroconversion to the vaccine or may have had the virus before receiving the vaccination. Furthermore, 10.9% of the HBV-infected individuals did not complete the full course of the vaccination.

Regarding comorbidities, 1.7% of patients were also HIV carriers in the present study. It is believed that this value may be even higher, because HIV in Rondônia tends to be underreported( 1313. Vieira GD, Alves TC, Sousa CM. Epidemiological evolution of vertical HIV transmission in Rondônia, Brazil. Braz J Infect Dis. 2013;17(5):613-4. , 1515. Vieira GD, Alves TC, Sousa CM. Perfil da aids em indivíduos acima de 50 anos na região amazônica. Rev Bras Geriatr Gerontol. 2014;17:75-80. ). Despite the low proportion of HIV, these patients should be routinely evaluated and with greater caution, because the acquired immunodeficiency syndrome (AIDS) associated with HBV causes deterioration of liver function in a short period of time, even with the use of anti-retroviral therapy( 33. Benhamou Y. Treatment algorithm for chronic hepatitis B in HIV-infected patients. J Hepatol 2006;44 (1 Suppl):90-94. ).

The costs of treatment for HBV and its complications are high, with average annual values for the following treatments: decompensated cirrhosis, R$20,184.50; hepatocellular carcinoma, R$5,000; and liver transplantation, R$87,372.60. These costs are comprised of medical fees, laboratory tests, and diagnostic procedures used to verify the patient’s condition, but do not include spending on antiviral therapy( 55. Castelo A, Pessoa MG, Barreto TC, Alves MR, Araujo DV. Cost estimates of chronic hepatitis B virus for the Brazilian unified health system in 2005. Rev Assoc Med Brás. 2007; 53(6):486-91. ). These costs highlight the importance of disease prevention, to avoid the high costs generated in the health system of Rondônia, which is considered an endemic region( 1111. Ministério da Saúde. (Brasil). Secretaria de Vigilância em Saúde. Departamento de DST, Aids e Hepatites Virais. Boletim Epidemiológico: hepatites Virais. Brasília: Ministério da Saúde; 2012. ).

In conclusion, hepatitis B is a serious health problem in the State of Rondônia, with high incidence rates that are progressively increasing. Better vaccination management is required by public health authorities, in view of the high rates of absence of immunization and incomplete vaccination. Thus, epidemiological surveillance and reporting systems are of extreme importance to control and prevent hepatitis B in the State of Rondônia, in order to identify failures and plan necessary measures for the prevention and control of the disease.

Author contribution

Vieira GD, Florão M, Castro KPO and Alves TC participated in the data collection, data interpretation, and manuscript writing processes. Vieira GD, Florão M, Castro KPO, Alves TC, Vaiciunas S, Honda ER, Camargo LMA and Sousa CM participated in the data interpretation and manuscript writing processes. All authors read and approved the final manuscript.

REFERENCES

  • 1
    Assunção AA, Araújo TMA, Ribeiro RBN, Oliveira SVS. Vacinação contra hepatite B e exposição ocupacional no setor saúde em Belo Horizonte, MG. Rev Saúde Pública. 2012;46:665-73.
  • 2
    Barros Júnior GM, Braga WSM, Oliveira CMC, Castilho MC, Araújo JR. Hepatite crônica B oculta: prevalência e aspectos clínicos em população de ele­vada endemicidade de infecção pelo vírus da hepatite B na Amazônia ocidental brasileira. Rev Soc Bras Med Trop. 2008;46:596-601.
  • 3
    Benhamou Y. Treatment algorithm for chronic hepatitis B in HIV-infected patients. J Hepatol 2006;44 (1 Suppl):90-94.
  • 4
    Camargo LMA, Moura MM, Engracia V, Pagotto RC, Basano SA, Silva LH, et al. A rural community in a Brazilian Western Amazonian Region: Some demographic and epidemiological patterns. Mem Inst Oswaldo Cruz 2002;97(2):193-5.
  • 5
    Castelo A, Pessoa MG, Barreto TC, Alves MR, Araujo DV. Cost estimates of chronic hepatitis B virus for the Brazilian unified health system in 2005. Rev Assoc Med Brás. 2007; 53(6):486-91.
  • 6
    Chávez JH, Campana SG, Haas P. Panorama da hepatite B no Brasil e no Estado de Santa Catarina. Rev Panam Salud Pública. 2003;14:91-6.
  • 7
    Cruz CR, Shirassu MM, Martins WP. [Comparison between hepatitis B and C epidemiological profiles at a public institution in São Paulo, Brazil]. Arq Gastroenterol. 2009;46:225-229.
  • 8
    Lobato C, Tavares-Neto J, Rios-Leite M, Trepo C, Vityitski L, Parvaz P, et al. Intrafamilial prevalence of hepatitis B virus in Western Brazilian Amazon region: epidemiologic and biomolecular study. J Gastroenterol Hepatol. 2006;21(5):863-8.
  • 9
    Luna EJA, Moraes JC, Silveira L, Salinas HSN. Eficácia e segurança da vacina brasileira contra hepatite B em recém-nascidos. Rev Saúde Pública. 2009;43:1014-20.
  • 10
    Ministério da Saúde. (Brasil). Fundação Nacional de saúde. Programa Nacional de Imunização: PNI 25 anos: Brasília, MS, 1998.
  • 11
    Ministério da Saúde. (Brasil). Secretaria de Vigilância em Saúde. Departamento de DST, Aids e Hepatites Virais. Boletim Epidemiológico: hepatites Virais. Brasília: Ministério da Saúde; 2012.
  • 12
    Oberle MW, Shapiro CN, Lanier AP. Preventing hepatitis B in people in close contact with hepatocellular carcinoma patients. Public Health Rep. 1997;112:63-5.
  • 13
    Vieira GD, Alves TC, Sousa CM. Epidemiological evolution of vertical HIV transmission in Rondônia, Brazil. Braz J Infect Dis. 2013;17(5):613-4.
  • 14
    Vieira GD, Ventura CG, Sousa CM. Occurrence and spatial distribution of hepatitis C in a western Brazilian Amazon State. Arq Gastroenterol. 2014;51(4);316-9.
  • 15
    Vieira GD, Alves TC, Sousa CM. Perfil da aids em indivíduos acima de 50 anos na região amazônica. Rev Bras Geriatr Gerontol. 2014;17:75-80.

Publication Dates

  • Publication in this collection
    Jan-Mar 2015

History

  • Received
    23 July 2014
  • Accepted
    3 Sept 2014
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