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Hepatitis B

12 July 2023

Key facts

  • Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease.

  • The virus is most commonly transmitted from mother to child during birth and delivery, in early childhood, as well as through contact with blood or other body fluids during sex with an infected partner, unsafe injections or exposures to sharp instruments.

  • WHO estimates that 296 million people were living with chronic hepatitis B infection in 2019, with 1.5 million new infections each year.

  • In 2019, hepatitis B resulted in an estimated 820 000 deaths, mostly from cirrhosis and hepatocellular carcinoma (primary liver cancer).

  • Hepatitis B can be prevented by vaccines that are safe, available and effective.

  • 1in 8 Sierra Leoneans suffers from chronic Hepatitis




Hepatitis B is an infection of the liver caused by the hepatitis B virus. The infection can be acute (short and severe) or chronic (long term).

Hepatitis B can cause a chronic infection and puts people at high risk of death from cirrhosis and liver cancer.

It can spread through contact with infected body fluids like blood, saliva, vaginal fluids and semen. It can also be passed from a mother to her baby.

Hepatitis B can be prevented with a safe and effective vaccine. The vaccine is usually given soon after birth with boosters a few weeks later. It offers nearly 100% protection against the virus.

Hepatitis B is a major global health problem. The burden of infection is highest in the WHO Western Pacific Region and the WHO African Region, where 116 million and 81 million people, respectively, are chronically infected. Sixty million people are infected in the WHO Eastern Mediterranean Region, 18 million in the WHO South-East Asia Region, 14 million in the WHO European Region and 5 million in the WHO Region of the Americas.

In 2020–2022 HBV prevalence estimates corresponded to 870,000 cases of chronic HBV infection (uncertainty interval, 610,000–1,213,000), or approximately one in nine people. The highest HBV seroprevalence estimates were among adolescents aged 10–17 years (17.0%; 95% CI, 8.8–30.5), Ebola survivors (36.8%; 95% CI, 26.2–48.8), people living with HIV (15.9%; 95% CI, 10.6–23.0), and those in the Northern Province (19.0%; 95% CI, 6.4–44.7) and Southern Province (19.7%; 95% CI, 10.9–32.8) regions.  Yendewa GA,. et al., (2023) Prevalence of Chronic Hepatitis B Virus Infection in Sierra Leone, 1997-2022 109(1):105-114.



In highly endemic areas, hepatitis B is most commonly spread from mother to child at birth (perinatal transmission) or through horizontal transmission (exposure to infected blood), especially from an infected child to an uninfected child during the first 5 years of life. The development of chronic infection is common in infants infected from their mothers or before the age of 5 years.

Hepatitis B is also spread by needle-stick injury, tattooing, piercing and exposure to infected blood and body fluids, such as saliva and menstrual, vaginal and seminal fluids. Transmission of the virus may also occur through the reuse of contaminated needles and syringes or sharp objects either in health care settings, in the community or among persons who inject drugs. Sexual transmission is more prevalent in unvaccinated persons with multiple sexual partners.

Hepatitis B infection acquired in adulthood leads to chronic hepatitis in less than 5% of cases, whereas infection in infancy and early childhood leads to chronic hepatitis in about 95% of cases. This is the basis for strengthening and prioritizing infant and childhood vaccination.

The hepatitis B virus can survive outside the body for at least 7 days. During this time, the virus can still cause infection if it enters the body of a person who is not protected by the vaccine. The incubation period of the hepatitis B virus ranges from 30 to 180 days. The virus may be detected within 30 to 60 days after infection and can persist and develop into chronic hepatitis B, especially when transmitted in infancy or childhood.



Most people do not experience any symptoms when newly infected.

Some people have acute illness with symptoms that last several weeks:

  • yellowing of the skin and eyes (jaundice)

  • dark urine

  • feeling very tired

  • nausea

  • vomiting

  • pain in the abdomen.


When severe, acute hepatitis can lead to liver failure, which can lead to death.

Although most people will recover from acute illness, some people with chronic hepatitis B will develop progressive liver disease and complications like cirrhosis and hepatocellular carcinoma (liver cancer). These diseases can be fatal.

HBV-HIV coinfection


About 1% of persons living with HBV infection (2.7 million people) are also infected with HIV. Conversely, the global prevalence of HBV infection in HIV-infected persons is 7.4%. Since 2015, WHO has recommended treatment for everyone diagnosed with HIV infection, regardless of the stage of disease. Tenofovir, which is included in the treatment combinations recommended as first-line therapy for HIV infection, is also active against HBV.



It is not possible on clinical grounds to differentiate hepatitis B from hepatitis caused by other viral agents; hence laboratory confirmation of the diagnosis is essential. Several blood tests are available to diagnose and monitor people with hepatitis B. Some laboratory tests can be used to distinguish acute and chronic infections, whilst other can assess and monitor the severity of liver disease. Physical examination, ultrasound, fibroscan can also be performed to assess degree of liver fibrosis and scarring and monitor progression of liver disease. WHO recommends that all blood donations be tested for hepatitis B to ensure blood safety and avoid accidental transmission.

As of 2019, 30.4 million people (10.5% of all people estimated to be living with hepatitis B) were aware of their infection, while 6.6 million (22%) of the people diagnosed were on treatment. According to latest WHO estimates, the proportion of children under five years of age chronically infected with HBV dropped to just under 1% in 2019 down from around 5% in the pre-vaccine era ranging from the 1980s to the early 2000s.

In settings with high Hepatitis B surface antigen seroprevalence in the general population (defined as >2% or >5% HBsAg seroprevalence), WHO recommends that all adults have access to and be offered HBsAg testing with linkage to prevention and care and treatment services as needed. WHO also recommends blood donor screening, routine testing for hepatitis B all pregnant women to provide the opportunity to institute measures for prevention of MTCT as well as focused or targeted testing of specific high-risk groups (including migrants from endemic regions, partners or family members of infected persons, and health-care workers PWID, people in prisons and other closed settings, MSM and sex workers, HIV-infected persons.



There is no specific treatment for acute hepatitis B. Chronic hepatitis B can be treated with medicines.

Care for acute hepatitis B should focus on making the person comfortable. They should eat a healthy diet and drink plenty of liquids to prevent dehydration from vomiting and diarrhoea.

Chronic hepatitis B infection can be treated with oral medicines, including tenofovir or entecavir.

Treatment can

  • slow the advance of cirrhosis

  • reduce cases of liver cancer

  • improve long term survival.


Most people who start hepatitis B treatment must continue it for life.

In 2021 WHO estimated that 12–25% of people with chronic hepatitis B infection will require treatment, depending on setting and eligibility criteria. The ongoing 2023 update of the WHO Hepatitis B treatment guidelines will expand treatment eligibility and increase the proportion of people on treatment.


In low-income settings, most people with liver cancer die within months of diagnosis. In high-income countries, patients present to hospital earlier in the course of the disease and have access to surgery and chemotherapy, which can prolong life for several months to a few years. Liver transplantation is sometimes used in people with cirrhosis or liver cancer in high-income countries, with varying success.



Hepatitis B is preventable with a vaccine.

All babies should receive the hepatitis B vaccine as soon as possible after birth (within 24 hours). This is followed by two or three doses of hepatitis B vaccine at least four weeks apart.

Booster vaccines are not usually required for people who have completed the three-dose vaccination series.

The vaccine protects against hepatitis B for at least 20 years and probably for life.

Hepatitis B can be passed from mother to child. This can be prevented by taking antiviral medicines to prevent transmission, in addition to the vaccine.

To reduce the risk of getting or spreading hepatitis B:

  • practice safe sex by using condoms and reducing the number of sexual partners

  • avoid sharing needles or any equipment used for injecting drugs, piercing, or tattooing

  • wash your hands thoroughly with soap and water after coming into contact with blood, body fluids, or contaminated surfaces

  • get a hepatitis B vaccine if working in a healthcare setting.

  • Fact sheets
    Hepatitis A Hepatitis B Hepatitis C Hepatitis D Hepatitis E Hepatitis B and C in Sierra Leone
  • Q & A
    What is hepatitis? Severe acute hepatitis of unknown cause in children How can I protect myself from hepatitis B?
  • HIV Prevention
    Using HIV Medication to Reduce Risk HIV treatment as prevention Pre-exposure prophylaxis Post-exposure prophylaxis Reducing Risk from Alcohol & Drug Use Alcohol and HIV risk Substance use and HIV risk
  • Q & A
    Details coming soon
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