Hepatitis B: Epidemiology & Clinical Features

Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV). It can cause chronic infection and puts people at high risk of death from cirrhosis and liver cancer.

In this first part of the article, we shall discuss the epidemiology, mode of transmission of Hepatitis B virus, its sign and symptoms, groups at risk, the relationship of HBV and HIV infection, and how the diagnosis is confirmed. In the second part of the article, you will read about treatment and the prevention of Hepatitis B.

Key facts 

  • Hepatitis B is a viral infection caused by hepatitis B virus (HBV).
  • HBV affects the liver and can cause both acute and chronic disease.
  • Chronic liver infection with HBV puts people at high risk of death from cirrhosis of the liver and liver cancer.
  • More than 686 000 people die every year due to consequences of hepatitis B. (2016 Data)
  • Children less than 6 years of age infected with the hepatitis B virus are most likely to develop chronic infections.
  • HBV is spread by contact with blood or body fluids of an infected person.
  • HBV is 50 to 100 times more infectious than HIV.
  • Hepatitis B vaccine and hepatitis B birth dose is the mainstay of hepatitis B prevention.
  • Disease epidemiology
  • Globally, an estimated 240 million people are chronically infected with HBV.
  • More than 686 000 people die every year due to complications of hepatitis B, including cirrhosis and liver cancer. (2016 Data)
  • Hepatitis B prevalence is highest in sub-Saharan Africa and East Asia.
  • In India, the prevalence of hepatitis B surface antigen (HBsAg) is 3-4.2% with over 40 million HBV carriers.
  • Every year over 115 000 Indians die of hepatitis B related complications.
  • There are 10 known HBV genotypes, classified from A to J. The most common genotype in India is D, followed by A and C. The identification of genotypes is important in prognosis and treatment of patients.


  • HBV is spread by contact with blood or body fluids of an infected person.
  • HBV is 50 to 100 times more infectious than HIV.
  • The main ways of getting infected with HBV are from mother to baby at birth (perinatal), child-to-child (especially in household settings), unsafe injections and transfusions and unprotected sexual contact.
  • Sharing items such as razors or toothbrushes with an infected person, direct contact with the blood or open sores of an infected person, unsafe tattoos/piercings and exposure to blood from needle sticks or other sharps can also lead to HBV transmission.


  • Many persons are asymptomatic but some persons have acute illness with symptoms that last several weeks, including yellow colour of skin and eyes (jaundice), dark-colour urine, extreme fatigue, nausea, vomiting and abdominal pain.
  • In some persons, the hepatitis B virus can lead to a chronic liver infection that can later develop into cirrhosis of the liver or liver cancer.
  • More than 90% of healthy adults who are infected with the hepatitis B virus will recover and be completely rid of the virus within 6 months.

Risks for chronic HBV

  • Children less than 6 years of age who become infected with the hepatitis B virus are most likely to develop chronic infections.
  • About 80-90% of infants and 30-50% of children infected before the age of 6 years develop chronic infections.
  • Less than 5% of otherwise healthy adults who are infected will develop chronic infection.
  • About 15-25% of adults who become chronically infected during childhood die from hepatitis B related liver cancer or cirrhosis.


  • Laboratory diagnosis of hepatitis B infection focuses on the detection of HBsAg.
  • Acute HBV infection is characterized by the presence of HBsAg and immunoglobulin M (IgM) antibody to the core antigen HBcAg.


Question: In most people, what are symptoms of hepatitis C when initially infected?

Answer: Most people do not experience symptoms


Most people (up to 80%) infected with Hepatitis C virus do not have any symptoms in the beginning. When symptoms do occur, they usually happen within 6 to 7 weeks after exposure to the virus. But symptoms can start any time from 2 weeks post-infection up to 6 months.

Early symptoms may include:

  •  Fever
  • Abdominal pain
  • Dark urine
  • Fatigue
  • Nausea/vomiting
  • Loss of appetite
  • Clay-colored bowel movements
  • Joint pain
  • Yellow color in the skin or eyes (jaundice)

Question: What is cirrhosis?

Answer: Scarring of the liver


Cirrhosis is scarring of the liver, due to permanent damage to liver tissue. This can occur secondary to infection with many infections, including Hepatitis C virus. HCV damages liver cells, causing them to die. This causes extensive scarring in the liver (fibrosis), which can lead to cirrhosis, a condition in which the liver is unable to function normally. If the damage is severe, liver failure can occur.

Question: Is it possible for the body to rid itself of hepatitis C?

Answer: Yes


Up to one-quarter of people infected with Hepatitis C will rid the virus from their bodies without treatment and not experience chronic infection. It is not understood why this occurs in some patients.

HCV patients need to find a doctor who specializes in HCV monitoring and treatment to avoid progression of the illness. Chronic liver disease can cause complex medical complications and it is important to have a specialist monitor the disease and prescribe any needed medical interventions. There are many new and promising medical treatments for Hepatitis C infection.

Epidemiology of Hepatitis B

Hepatitis B occurs in nearly every part of the world but is more common in some countries in Asia, Africa, South America and the Caribbean. Approximately 1% of the population of Australia and 3-4.2% of the population of India suffer from chronic Hepatitis B.

The people infected with Hepatitis B can pass the virus to other people from two weeks before the development of symptoms till one week after the appearance of the symptoms.

A person infected with Hepatitis B begins to be contagious and remains the same during the incubation period of Hepatitis. Approximately fifty percent of the people remain contagious up to a period of two months (eight weeks) of the appearance of symptoms. The remaining fifty percent who do not develop chronic hepatitis B will usually remain contagious up to 15 weeks once the symptoms begin. A person who develops chronic Hepatitis B will remain contagious indefinitely.

Transmission of Hepatitis B

In profoundly endemic zones, hepatitis B is most normally spread from mother to youngster upon entering the world (perinatal transmission), or through horizontal transmission (openness to tainted blood), particularly from a contaminated kid to an uninfected kid during the initial 5 years of life. The advancement of persistent disease is basic in babies contaminated from their moms or before the age of 5 years.

Hepatitis B is additionally spread by needlestick injury, inking, penetrating, and openness to tainted blood and body liquids, like salivation and, feminine, vaginal, and fundamental liquids. Sexual transmission of hepatitis B may happen, especially in unvaccinated men who have intercourse with men and hetero people with various sex accomplices or contact with sex laborers.

Disease in adulthood prompts persistent hepatitis in under 5% of cases, while contamination in the outset and youth prompts ongoing hepatitis in about 95% of cases. Transmission of the infection may likewise happen through the reuse of needles and needles either in medical care settings or among people who infuse drugs. Also, the disease can happen during clinical, careful, and dental systems, through inking, or using razors and comparable articles that are tainted with contaminated blood.

The hepatitis B infection can make due external to the body for at any rate 7 days. During this time, the infection can in any case cause contamination if it enters the body of an individual who isn’t ensured by the antibody. The brooding time of the hepatitis B infection is 75 days overall, yet can change from 30 to 180 days. The infection might be identified within 30 to 60 days after the disease and can persevere and form into persistent hepatitis B.

Symptoms of Hepatitis B

The vast majority don’t encounter any side effects when recently tainted. Nonetheless, a few groups have intense sickness with manifestations that most recent a little while, including yellowing of the skin and eyes (jaundice), dim pee, extraordinary weakness, queasiness, retching, and stomach torment. A little subset of people with intense hepatitis can create intense liver disappointment, which can prompt passing.

In certain individuals, the hepatitis B infection can likewise cause a constant liver disease that can later form into cirrhosis (a scarring of the liver) or liver malignant growth.

Who is in danger of persistent illness?

The probability that contamination becomes ongoing relies upon the age at which an individual gets tainted. Kids under 6 years old who become contaminated with the hepatitis B infection are destined to create ongoing diseases.

In babies and kids:

  • 80–90% of babies contaminated during the main year of life create persistent diseases; and
  • 30–50% of the kids contaminated before the age of 6 years create constant diseases.

In grown-ups:

  • under 5% of in any case sound people who are contaminated as grown-ups will create constant diseases; and
  • 20–30% of grown-ups who are constantly contaminated will create cirrhosis as well as liver malignancy.

HBV-HIV coinfection

About 1% of people living with HBV contamination (2.7 million individuals) are additionally tainted with HIV. On the other hand, the worldwide commonness of HBV disease in HIV-contaminated people is 7.4%. Since 2015, WHO has suggested treatment for everybody determined to have HIV contamination, paying little mind to the phase of sickness. Tenofovir, which is remembered for the treatment mixes suggested as first-line treatment for HIV disease, is additionally dynamic against HBV.

Diagnosis of Hepatitis B

It is beyond the realm of imagination, on clinical grounds, to separate hepatitis B from hepatitis brought about by other viral specialists, henceforth, research center affirmation of the analysis is fundamental. Various blood tests are accessible to determine and screen individuals to have hepatitis B. They can be utilized to recognize intense and persistent diseases.

Lab determination of hepatitis B contamination centers around the recognition of the hepatitis B surface antigen HBsAg. WHO suggests that all blood gifts be tried for hepatitis B to guarantee blood security and maintain a strategic distance from the inadvertent transmission to individuals who get blood items.

Intense HBV contamination is portrayed by the presence of HBsAg and immunoglobulin M (IgM) counter-acting agent to the center antigen HBcAg. During the underlying period of the disease, patients are additionally seropositive for hepatitis B e antigen (HBeAg). HBeAg is generally a marker of undeniable degrees of replication of the infection. The presence of HBeAg demonstrates that the blood and body liquids of the contaminated individual are exceptionally irresistible.

Ongoing contamination is portrayed by the steadiness of HBsAg for at any rate a half year (with or without simultaneous HBeAg). Determination of HBsAg is the essential marker of danger for creating persistent liver infection and liver malignant growth (hepatocellular carcinoma) further down the road.

Read further in part 2: Hepatitis B: Treatment & Prevention 

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