Understanding How Common Chronic Hepatitis B Is

Chronic hepatitis B represents a significant global health challenge. According to the World Health Organization, approximately 254 million people worldwide were living with chronic hepatitis B infection in 2022, with around 1.2 million new infections occurring each year.^[7] The disease burden varies considerably across different regions of the world, with the highest numbers of affected individuals found in the Western Pacific and African regions.

In the United States, the Centers for Disease Control and Prevention estimates that about 640,000 adults currently have chronic hepatitis B.^[3] However, a concerning reality is that about one in two people with hepatitis B do not know they are infected.^[3] This lack of awareness can delay necessary medical care and increase the risk of transmitting the virus to others.

The distribution of chronic hepatitis B is not uniform across all populations. In the United States, rates of chronic infection are notably higher among certain groups. In 2023, the rate of newly reported chronic hepatitis B cases among non-Hispanic Asian and Pacific Islander people was 9.9 times as high as the rate among non-Hispanic White people.^[3] Additionally, three out of four people with chronic hepatitis B in the United States are immigrants from regions of the world where hepatitis B is more common.^[6]

The global impact of this infection is profound. In 2022, hepatitis B resulted in an estimated 1.1 million deaths worldwide, primarily from complications such as cirrhosis (severe scarring of the liver) and hepatocellular carcinoma (primary liver cancer).^[7] These statistics underscore the importance of screening, prevention, and appropriate management of chronic hepatitis B.

What Causes Chronic Hepatitis B

Chronic hepatitis B develops when the body cannot clear the hepatitis B virus within six months of initial infection. When a person is first infected with the hepatitis B virus, this initial phase is called acute hepatitis B, which is a short-term illness lasting less than six months.^[1] For some people, the immune system successfully fights off the virus during this acute phase, and they recover completely. However, when the infection persists beyond six months, it becomes chronic hepatitis B, which is a lifelong condition.^[2]

The hepatitis B virus spreads through contact with infected bodily fluids. The virus can be present in blood, semen, vaginal fluids, saliva, menstrual fluid, and amniotic fluid from someone who has the infection.^[5] Transmission can occur through several pathways, including sharing needles or syringes with someone who has the virus, having unprotected sexual contact with an infected person, or accidental exposure to contaminated medical instruments.^[5]

In regions where hepatitis B is highly common, the virus is most frequently spread from mother to child during birth and delivery. This is called perinatal transmission.^[7] The virus can also spread through what is called horizontal transmission, especially among young children during the first five years of life. In these cases, the virus may pass from an infected child to an uninfected child through close contact.^[7]

Transmission can also happen through needlestick injuries in healthcare settings, tattooing or piercing with unsterilized equipment, and sharing personal items that might have come into contact with infected blood, such as razors or toothbrushes.^[7] Sexual transmission is more common in adults and occurs through intimate contact with infected bodily fluids.

Who Is at Higher Risk

Certain groups of people face a higher likelihood of developing chronic hepatitis B or being exposed to the virus. Understanding these risk factors can help individuals and healthcare providers identify who needs screening and vaccination.

People who were born in regions where hepatitis B is common have a significantly higher risk. This includes countries in Asia, South America, Africa, the Middle East, and the Caribbean.^[19] Additionally, individuals whose parents were born in areas where hepatitis B is widespread are also at increased risk, even if they themselves were born elsewhere.

Individuals who inject drugs and share needles or syringes are at high risk of contracting hepatitis B. The virus can spread through even microscopic amounts of infected blood left on equipment.^[3] Similarly, people who live with or have sexual contact with someone who has hepatitis B face elevated risk due to the possibility of transmission through bodily fluids.

Men who have sex with men represent another higher-risk group for hepatitis B infection.^[19] People with multiple sexual partners or a history of sexually transmitted infections also have increased exposure risk. Healthcare workers and others who might experience needlestick injuries or exposure to blood in occupational settings need to be particularly vigilant.

Certain medical conditions and treatments also increase vulnerability to hepatitis B. People with HIV, hepatitis C, or other liver diseases are at higher risk.^[19] Those receiving kidney dialysis, taking medications that suppress the immune system (such as drugs used to prevent organ transplant rejection), or individuals who have spent time in jail or prison also face elevated risk.^[5]

It’s important to note that anyone can get hepatitis B regardless of these risk factors, which is why universal screening recommendations have expanded in recent years. The CDC now recommends that all adults aged 18 years and older should be tested for hepatitis B at least once during their lifetime.^[6]

Recognizing the Symptoms

One of the most challenging aspects of chronic hepatitis B is that many people with the infection experience no symptoms at all, especially in the early stages. In fact, most people with chronic hepatitis B have no symptoms and feel completely healthy.^[6] This is why hepatitis B is sometimes called a “silent killer” – even when you don’t feel sick, the virus may be active and quietly causing liver damage.^[6]

When symptoms do occur, they can be quite varied and may come and go depending on the phase of the infection. Common symptoms of chronic hepatitis B include pain in the upper right area of the abdomen, where the liver is located. People may also experience persistent fatigue and weakness, making everyday activities feel more tiring than usual.^[1]

Digestive symptoms are also common when they appear. These can include loss of appetite, nausea, and vomiting. Some people notice that their urine becomes darker than normal, or that their bowel movements appear light-colored or clay-colored.^[1] These changes occur because of how the damaged liver processes certain substances.

As liver disease progresses, additional symptoms may develop. Jaundice, which is a yellowing of the skin and the whites of the eyes, can occur when the liver is unable to properly process a substance called bilirubin. Depending on a person’s natural skin color, this yellowing may be harder or easier to notice.^[1] Some people may develop swelling in their belly, arms, or legs due to fluid accumulation, which happens when the liver can no longer maintain proper fluid balance in the body.

Joint pain and fever may also occur in some individuals with chronic hepatitis B.^[1] However, it’s crucial to understand that the absence of symptoms does not mean the absence of liver damage. Many people with chronic hepatitis B have liver inflammation and scarring developing silently without feeling any different than usual.

Preventing Hepatitis B Infection

Prevention of hepatitis B centers primarily on vaccination, which represents the most effective way to avoid infection. The hepatitis B vaccine is safe, widely available, and offers nearly 100% protection against the virus.^[7] The vaccine is typically given as a series of shots, and all doses in the series must be completed to ensure full protection.

Current vaccination recommendations are comprehensive. All infants should receive the hepatitis B vaccine soon after birth, with additional booster doses given a few weeks later.^[7] Any babies or children 18 years or younger who did not receive the vaccine at birth should get it as soon as possible. Adults between ages 19 and 59 years who haven’t been vaccinated yet should receive the hepatitis B vaccine unless they’ve already been vaccinated.^[6] For people age 60 years or older, vaccination is recommended for those at higher risk, though anyone in this age group can choose to get vaccinated if they wish.

Beyond vaccination, several behavioral measures can help prevent hepatitis B transmission. People should avoid sharing needles, syringes, or any drug injection equipment. Using barrier protection such as condoms during sexual activity can significantly reduce transmission risk. Individuals should not share personal items that might have contact with blood, such as razors, toothbrushes, or nail clippers.

For healthcare workers and others at risk of occupational exposure, following proper infection control procedures is essential. This includes using personal protective equipment, properly disposing of sharps, and receiving appropriate postexposure treatment if an exposure occurs. If exposed to hepatitis B, receiving treatment within 24 hours is most effective for preventing infection.^[20]

Pregnant women who have hepatitis B can take steps to protect their babies. If a pregnant woman has high levels of the virus in her blood, she may be given antiviral medications during the last three months of pregnancy to reduce the risk of transmission to her baby.^[8] All babies born to mothers with hepatitis B should receive both the hepatitis B vaccine and hepatitis B immune globulin (HBIG) immediately after birth to provide maximum protection.

How Chronic Hepatitis B Affects the Body

Chronic hepatitis B causes ongoing inflammation in the liver, which is the body’s largest internal organ and performs hundreds of vital functions. The liver filters toxins from the blood, produces proteins necessary for blood clotting, stores energy, makes bile for digestion, and processes medications. When the hepatitis B virus infects liver cells, it uses them to reproduce, and the immune system’s response to this infection causes inflammation and damage to liver tissue.

The progression of liver disease in chronic hepatitis B is closely linked to the amount of virus present in the blood, measured as the viral load. When viral DNA levels are high, more active replication is occurring, which typically means more liver inflammation and faster disease progression.^[4] The disease doesn’t follow the same pattern in everyone – chronic hepatitis B can be divided into different phases based on how active the virus is and how much damage is occurring.

Over time, repeated cycles of inflammation and healing can lead to fibrosis, which is the formation of scar tissue in the liver. As fibrosis progresses, it can develop into cirrhosis, where extensive scarring interferes with the liver’s structure and function.^[1] Without treatment, between 8 and 20% of people with chronic hepatitis B develop cirrhosis over a five-year period.^[4] Once cirrhosis develops, there is a significant risk of the liver failing to perform its essential functions, a condition known as decompensated liver disease. People with untreated decompensated cirrhosis may have five-year survival rates as low as 15%.^[4]

Chronic hepatitis B also substantially increases the risk of developing liver cancer, specifically hepatocellular carcinoma. In fact, chronic hepatitis B is the leading cause of liver cancer worldwide.^[5] Liver cancer can occur at any stage of chronic hepatitis B infection, even before cirrhosis develops, though the risk is higher in people with more advanced liver disease.^[6]

The virus can also affect other organs beyond the liver. People with chronic hepatitis B may develop kidney disease, bone disease, diabetes, and heart disease.^[6] Additionally, some individuals with chronic hepatitis B may also become infected with hepatitis D virus, which can only infect people who already have hepatitis B. When both viruses are present together without treatment, up to 70% of affected individuals develop cirrhosis.^[8]

Not everyone with chronic hepatitis B experiences active liver damage all the time. The infection can go through different phases where the virus is more or less active. During what’s called the “immune control” phase, the immune system keeps the virus suppressed and little or no liver damage occurs.^[22] However, the virus can reactivate later, particularly if a person takes medications that suppress the immune system or stops antiviral treatment. Understanding these patterns helps doctors determine when treatment is needed and when careful monitoring is sufficient.