“The vast majority of people infected with hepatitis are unaware, undiagnosed and untreated,” says Dr Sylvie Briand of WHO’s Pandemic and Epidemic Disease Department. “Only by increasing awareness of the different forms of hepatitis, and how they can be prevented and treated, can we take the first step towards full control of the disease and save thousands of lives.” Here we will explain the three most common types of hepatitis:
1.4 million estimated cases occur annually
- Hepatitis A is a viral liver disease that can cause mild to severe illness.
- The hepatitis A virus is transmitted through ingestion of contaminated food and water, or through direct contact with an infectious person.
- Globally, there are an estimated 1.4 million cases of hepatitis A every year.
- Hepatitis A is associated with a lack of safe water and poor sanitation.
- Epidemics can be explosive in growth and cause significant economic losses.
- Improved sanitation and the hepatitis A vaccine are the most effective ways to combat the disease.
The incubation period of hepatitis A is usually 14–28 days.
Symptoms of hepatitis A range from mild to severe, and can include fever, malaise, loss of appetite, diarrhoea, nausea, abdominal discomfort, dark-coloured urine and jaundice (a yellowing of the skin and whites of the eyes). Not everyone who is infected will have all of the symptoms.
Adults have signs and symptoms of illness more often than children, and the severity of disease and mortality increases in older age groups. Infected children under six years of age do not usually experience noticeable symptoms, and only 10% develop jaundice. Among older children and adults, infection usually causes more severe symptoms, with jaundice occurring in more than 70% of cases.
Improved sanitation, food safety and immunization are the most effective ways to combat hepatitis A.
The spread of hepatitis A can be reduced by:
- adequate supplies of safe drinking water
- proper disposal of sewage within communities
- personal hygiene practices such as regular hand washing with safe water.
Several hepatitis A vaccines are available internationally. All are similar in terms of how well they protect people from the virus and their side-effects. No vaccine is licensed for children younger than one year of age.
Nearly 100% of people develop protective levels of antibodies to the virus within one month after a single dose of the vaccine. Even after exposure to the virus, a single dose of the vaccine within two weeks of contact with the virus has protective effects. Still, manufacturers recommend two vaccine doses to ensure a longer-term protection of about five to eight years after vaccination.
Millions of people have been immunized worldwide with no serious adverse events. The vaccine can be given as part of regular childhood immunizations programmes and can also be given with other vaccines for travellers.
2 billion people (estimated) worldwide have been infected with the virus
- Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease.
- The virus is transmitted through contact with the blood or other body fluids of an infected person.
- Two billion people worldwide have been infected with the virus and about 600 000 people die every year due to the consequences of hepatitis B.
- The hepatitis B virus is 50 to 100 times more infectious than HIV.
- Hepatitis B is an important occupational hazard for health workers.
- Hepatitis B is preventable with the currently available safe and effective vaccine.
Most people do not experience any symptoms during the acute infection phase. However, some people have acute illness with symptoms that last several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, vomiting and abdominal pain.
In some people, the hepatitis B virus can also cause a chronic liver infection that can later develop into cirrhosis of the liver or liver cancer.
The hepatitis B vaccine is the mainstay of hepatitis B prevention. WHO recommends that all infants receive the hepatitis B vaccine.
The vaccine can be given as either three or four separate doses, as part of existing routine immunization schedules. In areas where mother-to-infant spread of the hepatitis B virus is common, the first dose of vaccine should be given as soon as possible after birth (i.e. within 24 hours).
The complete vaccine series induces protective antibody levels in more than 95% of infants, children and young adults. Protection lasts at least 20 years and is possibly lifelong.
All children and adolescents younger than 18 years old and not previously vaccinated should receive the vaccine. People in high risk groups should also be vaccinated, including:
- people with high-risk sexual behaviour
- partners and household contacts of infected people
- injecting drug users
- people who frequently require blood or blood products
- recipients of solid organ transplantation
- people at occupational risk of hepatitis B virus infection, including health-care workers
- travellers to countries with high rates of hepatitis B.
The vaccine has an outstanding record of safety and effectiveness. Since 1982, over one billion doses of hepatitis B vaccine have been used worldwide. In many countries, where 8–15% of children used to become chronically infected with the hepatitis B virus, vaccination has reduced the rate of chronic infection to less than 1% among immunized children.
As of July 2011, 179 countries vaccinate infants against hepatitis B as part of their vaccination schedules – a major increase compared with 31 countries in 1992, the year that the World Health Assembly passed a resolution to recommend global vaccination against hepatitis B.
150 million people are chronically infected with the virus
- Hepatitis C is a liver disease caused by the hepatitis C virus.
- The disease can range in severity from a mild illness lasting a few weeks to a serious, lifelong condition that can lead to cirrhosis of the liver or liver cancer.
- The hepatitis C virus is transmitted through contact with the blood of an infected person.
- About 150 million people are chronically infected with hepatitis C virus, and more than 350 000 people die every year from hepatitis C-related liver diseases.
- Hepatitis C is curable using antivirals.
- There is currently no vaccine for hepatitis C; however, research in this area is ongoing.
The incubation period for hepatitis C is 2 weeks to 6 months. Following initial infection, approximately 80% of people do not exhibit any symptoms. Those people who are acutely symptomatic may exhibit fever, fatigue, decreased appetite, nausea, vomiting, abdominal pain, dark urine, grey-coloured faeces, joint pain and jaundice (yellowing of skin and the whites of the eyes).
About 75-85 % of newly infected persons develop chronic disease and 60–70% of chronically infected people develop chronic liver disease; 5–20% develop cirrhosis and 1–5% die from cirrhosis or liver cancer. In 25 % of liver cancer patients, the underlying cause is hepatitis C.
There is no vaccine for hepatitis C. The risk of infection can be reduced by avoiding:
- unnecessary and unsafe injections;
- unsafe blood products;
- unsafe sharps waste collection and disposal;
- use of illicit drugs and sharing of injection equipment;
- unprotected sex with hepatitis C-infected people;
- sharing of sharp personal items that may be contaminated with infected blood;
- tattoos, piercings and acupuncture performed with contaminated equipment.
Secondary and tertiary prevention
For people infected with the hepatitis C virus, WHO recommends:
- education and counseling on options for care and treatment;
- immunization with the hepatitis A and B vaccines to prevent coinfection from these hepatitis viruses to protect their liver;
- early and appropriate medical management including antiviral therapy if appropriate; and
- regular monitoring for early diagnosis of chronic liver disease.
Article courtesy of the World Health Organisation (WHO)