Hepatitis B: Challenges in Access and Treatment

In Brazil, the hepatitis B vaccine is provided free of charge by the Unified Health System and has been available to people of all ages since 2016 (source ID 1). Despite this, access to the vaccine remains a challenge in remote regions, particularly in large parts of the Amazon and the North Region, where long distances, limited transportation, and low health service availability hinder vaccination, diagnosis, and medical follow-up (source ID 1). These logistical barriers may leave some individuals, especially those born before the vaccination schedule was expanded or who lacked access to health services, at continued risk of infection (source ID 1). [1]

Hepatitis B can remain asymptomatic for long periods, with many people discovering the infection only during routine exams, blood donations, prenatal visits, or investigations into other health conditions (source ID 1). In 2025, approximately 4,600 confirmed cases were recorded in Brazil, according to the Ministry of Health. These figures represent detected and reported cases, not necessarily all infections acquired in the same year (source ID 1). The virus can progress to chronic infection, which may lead to severe complications such as cirrhosis, liver failure, and liver cancer if left untreated (source ID 1). [1]

According to the World Health Organization (WHO), approximately 240 million people were living with chronic hepatitis B infection in 2024, with 0.9 million new infections each year (source ID 2). Chronic infection is more likely to occur in individuals infected during infancy or early childhood, with a 95% chance of developing chronic hepatitis compared to less than 5% in adults (source ID 2). In Brazil, the Unified Health System offers free treatment to patients who need it, including medications such as tenofovir and entecavir, which block the replication of the hepatitis B virus (source ID 1). [1] [2]

In Brazil, the hepatitis B vaccine is provided free of charge by the Unified Health System and has been available to people of all ages since 2016 (source ID 1). However, access to the vaccine remains uneven, particularly in remote areas such as the Amazon and the North Region of the country, where long distances, limited transportation, and low health service availability hinder vaccination, diagnosis, and medical follow-up (source ID 1). These challenges contribute to disparities in vaccination coverage and increase the risk of infection for populations in these regions (source ID 1). [1]

Hepatitis B can remain asymptomatic for long periods, with many people discovering the infection only during routine exams, blood donations, prenatal visits, or investigations into other health conditions (source ID 1). In 2025, approximately 4,600 confirmed cases were recorded in Brazil, according to the Ministry of Health. These figures represent detected and reported cases, not necessarily all infections acquired in the same year (source ID 1). The asymptomatic nature of the infection complicates early detection and intervention, further emphasizing the importance of broad access to the vaccine and regular health screenings (source ID 1). [1]

According to the World Health Organization (WHO), approximately 240 million people were living with chronic hepatitis B infection in 2024, with 0.9 million new infections each year (source ID 2). In Brazil, the Unified Health System offers free treatment to patients who need it, including medications such as tenofovir and entecavir, which block a key step in the replication of the hepatitis B virus (source ID 1). However, controlling the virus's replication does not eliminate it, as persistent forms of viral DNA may remain in liver cells, making a complete cure difficult to achieve (source ID 1). [1] [2]

RNA interference (RNAi) is a promising strategy for targeting viral proteins in hepatitis B. This approach uses small RNA molecules to selectively intercept and destroy messenger RNA before it delivers its instructions, which can be used to produce viral proteins (source ID 3). In the case of the hepatitis B virus, RNAi can be engineered to recognize RNA molecules responsible for the production of viral proteins, including HBsAg. By eliminating these molecules, the strategy reduces the amount of viral proteins produced by the cell (source ID 1). [3] [1]

RNAi technology is already used in approved medications for various diseases, including some that affect the liver. In the case of the hepatitis B virus, different RNAi molecules can be designed to recognize specific regions of the viral genetic material, allowing them to target different viral proteins (source ID 3). There are multiple RNAi therapies for hepatitis B virus in early-phase clinical trials. In the laboratory, researchers have introduced the hepatitis B virus RNA into cultured liver cells and tested various RNAi-based candidates (source ID 1). [3] [1]

Among the candidates evaluated, one showed the most promising results, with a reduction in HBsAg levels in the cell cultures. This result is still preliminary. The model used allows researchers to assess viral protein production, but it does not replicate all the steps of a natural infection. Therefore, further verification is needed to determine whether the effect persists over longer periods and whether it also occurs in cellular models that better reproduce hepatitis B infection (source ID 1). [1]

Sources

Medical Xpress

www.who.int

news.mit.edu

Prepared with AI assistance from the cited sources.