A phlebotomist holds a blood-filled, purple-tipped, vacutainer test tube. Exposures to blood and other body fluids occur across a wide variety of occupations. Healthcare workers, emergency response and public safety personnel, and other workers can be exposed to blood through needlestick and other sharps injuries, mucous membrane, and skin exposures. The pathogens of primary concern are the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). Workers and employers are urged to take advantage of available engineering controls and work practices, to prevent exposure to blood and other body fluids. Image courtsey of CDC/Amanda Mills
World Hepatitis Day 2012 takes place on July 28, 2012 and this year's theme is Its closer than you think." The campaign focuses on raising awareness of the different forms of hepatitis: what they are and how they are transmitted; who is at risk; and the various methods of prevention and treatment. Despite its staggering toll on health, hepatitis remains a group of diseases that are largely unknown, undiagnosed and untreated, according to the World Health Organization (WHO).
- Hepatitis A is a viral liver disease that can cause mild to severe illness.
- Globally, there are an estimated 1.4 million cases of hepatitis A every year.
- The hepatitis A virus is transmitted through ingestion of contaminated food and water, or through direct contact with an infectious person.
- 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 hepatitis A virus is one of the most frequent causes of foodborne infection. Epidemics related to contaminated food or water can erupt explosively, such as the epidemic in Shanghai in 1988 that affected about 300 000 people. Hepatitis A viruses persist in the environment and can resist food-production processes routinely used to inactivate and/or control bacterial pathogens.
The disease can wreak significant economic and social consequences in communities. It can take weeks or months for people recovering from the illness to return to work, school or daily life. The impact on food establishments identified with the virus, and local productivity in general, can be substantial.
Geographical areas can be characterized as having high, intermediate or low levels of hepatitis A infection.
- Areas with high levels of infection: In developing countries with very poor sanitary conditions and hygienic practices, most children (90%) have been infected with the hepatitis A virus before the age of 10 years old. Those infected in childhood do not experience any noticeable symptoms. Epidemics are uncommon because older children and adults are generally immune. Symptomatic diseases rates in these areas are low and outbreaks are rare.
- Areas with intermediate levels of infection: In developing countries, countries with transitional economies, and regions where sanitary conditions are variable, children often escape infection in early childhood. Ironically, these improved economic and sanitary conditions may lead to a higher susceptibility in older age groups and higher disease rates, as infections occur in adolescents and adults, and large outbreaks can occur.
- Areas with low levels of infection: In developed countries with good sanitary and hygienic conditions, infection rates are low. Disease may occur among adolescents and adults in high-risk groups, such as injecting-drug users, homosexual men, people travelling to areas of high endemicity, and in isolated populations such as closed religious communities.
The hepatitis A virus is transmitted primarily by the fecal-oral route. This is when an uninfected person ingests food or water that has been contaminated with the faeces of an infected person. Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated water. The virus can also be transmitted through close physical contact with an infectious person, although casual contact among people does not spread the virus.
The incubation period of hepatitis A is usually 14 to 28 days. Symptoms of hepatitis A range from mild to severe, and can include fever, malaise, loss of appetite, diarrhea, 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 percent develop jaundice. Among older children and adults, infection usually causes more severe symptoms, with jaundice occurring in more than 70 percent of cases.
Who is at risk?
Anyone who has not been vaccinated or previously infected can contract hepatitis A. In areas where the virus is widespread (high endemicity), most hepatitis A infections occur during early childhood. Risk factors include: poor sanitation, lack of safe water, injecting drugs, living in a household with an infected person, being a sexual partner of someone with acute hepatitis A infection, and travelling to areas of high endemicity without being immunized.
There is no specific treatment for hepatitis A. Recovery from symptoms following infection may be slow and take several weeks or months. Therapy is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids that are lost from vomiting and diarrhea.
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 percent 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.
Vaccination against hepatitis A should be part of a comprehensive plan for the prevention and control of viral hepatitis. Planning for large-scale immunization programs should involve careful economic evaluations and consider alternative or additional prevention methods, such as improved sanitation, and health education for improved hygiene practices. Whether or not to include the vaccine in routine childhood immunizations depends on the local context, including the proportion of susceptible people in the population and the level of exposure to the virus. Several countries, including Argentina, China, Israel and the United States have introduced the vaccine in routine childhood immunizations. While the two-dose regimen of inactivated hepatitis A vaccine is used in many countries, other countries may consider inclusion of a single-dose inactivated hepatitis A vaccine in their immunization schedules. Regarding immunization for outbreak response, recommendations for hepatitis A vaccination should also be site-specific, including the feasibility of rapidly implementing a widespread immunization campaign. Vaccination to control community-wide outbreaks is most successful in small communities, when the campaign is started early and when high coverage of multiple age groups is achieved. Vaccination efforts should be supplemented by health education to improve sanitation, hygiene practices and food safety.
- 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.
Hepatitis B virus can cause an 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. People can Hepatitis B is endemic in China and other parts of Asia. Most people in this region become infected with the hepatitis B virus during childhood and 8 percent to 10 percent of the adult population is chronically infected. Liver cancer caused by hepatitis B is among the first three causes of death from cancer in men, and a major cause of cancer in women in this region. High rates of chronic infections are also found in the Amazon and the southern parts of eastern and central Europe. In the Middle East and Indian subcontinent, an estimated 2 percent to 5 percent of the general population is chronically infected. Less than 1 percent of the population in western Europe and North America is chronically infected.
Hepatitis B virus is transmitted between people by direct blood-to-blood contact or semen and vaginal fluid of an infected person. Modes of transmission are the same as those for the human immunodeficiency virus (HIV), but the hepatitis B virus is 50 to 100 times more infectious. Unlike HIV, the hepatitis B virus can survive outside the body for at least seven 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.
In developing countries, common modes of transmission are:
- perinatal (from mother to baby at birth)
- early childhood infections (inapparent infection through close interpersonal contact with infected household contacts)
- unsafe injection practices
- unsafe blood transfusions
- unprotected sexual contact.
In many developed countries (e.g. those in western Europe and North America), patterns of transmission are different from those in developing countries. The majority of infections in developed countries are transmitted during young adulthood by sexual activity and injecting drug use. Hepatitis B is a major infectious occupational hazard of health workers.
The hepatitis B virus is not spread by contaminated food or water, and cannot be spread casually in the workplace.
The incubation period of the hepatitis B virus is 90 days on average, but can vary from 30 to 180 days. The virus may be detected 30 to 60 days after infection and persists for variable periods of time.
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.
Who is at risk for chronic disease?
The likelihood that infection with the hepatitis B virus becomes chronic depends upon the age at which a person becomes infected. Young children who become infected with the hepatitis B virus are the most likely to develop chronic infections:
90 percent of infants infected during the first year of life develop chronic infections;
30 percent to 50 percent of children infected between one to four years of age develop chronic infections.
- 25 percent of adults who become chronically infected during childhood die from hepatitis B-related liver cancer or cirrhosis;
- 90 percent of healthy adults who are infected with the hepatitis B virus will recover and be completely rid of the virus within six months.
A number of blood tests are available to diagnose and monitor people with hepatitis B. They can be used to distinguish acute and chronic infections. Laboratory diagnosis of hepatitis B infection centres on the detection of the hepatitis B surface antigen HBsAg. A positive test for the hepatitis B surface antigen (HBsAg) indicates that the person has an active infection (either acute or chronic). WHO recommends that all blood donations are tested for this marker to avoid transmission to recipients.
Other commonly used tests include the following:
- testing for antibodies to the hepatitis B surface antigen a positive test indicates that the person has either recovered from an acute infection and cleared the virus, or has received a hepatitis B vaccine. The person is immune to future hepatitis B infection and is no longer contagious.
- testing for antibodies to the hepatitis B core antigen a positive test indicates that the person has had a recent infection or an infection in the past. Combined with a positive test for the hepatitis B surface antigen, a positive test usually indicates a chronic infection.
There is no specific treatment for acute hepatitis B. Care is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids that are lost from vomiting and diarrhea. Some people with chronic hepatitis B can be treated with drugs, including interferon and antiviral agents. Treatment can cost thousands of dollars per year and is not available to most people in developing countries. Liver cancer is almost always fatal and often develops in people at an age when they are most productive and have family responsibilities. In developing countries, most people with liver cancer die within months of diagnosis. In high-income countries, surgery and chemotherapy can prolong life for up to a few years. People with cirrhosis are sometimes given liver transplants, with varying success.
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 percent 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 behavior
- 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
- travelers to countries with high rates of hepatitis B.
The vaccine has an outstanding record of safety and effectiveness. Since 1982, over 1 billion doses of hepatitis B vaccine have been used worldwide. In many countries, where 8 percent to 15 percent of children used to become chronically infected with the hepatitis B virus, vaccination has reduced the rate of chronic infection to less than 1 percent 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.
- 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.
Hepatitis C is found worldwide. Countries with high rates of chronic infection are Egypt (22 percent), Pakistan (4.8 percent) and China (3.2 percent). The main mode of transmission in these countries is attributed to unsafe injections using contaminated equipment.
The hepatitis C virus is most commonly transmitted through exposure to infectious blood. This can occur through:
- receipt of contaminated blood transfusions, blood products and organ transplants;
- injections given with contaminated syringes and needlestick injuries in healthcare settings;
- injection drug use;
- being born to a hepatitis C-infected mother.
Hepatitis C may be transmitted through sex with an infected person or sharing of personal items contaminated with infectious blood, but these are less common. Hepatitis C is not spread through breast milk, food or water or by casual contact such as hugging, kissing and sharing food or drinks with an infected person.
The incubation period for hepatitis C is 2 weeks to 6 months. Following initial infection, approximately 80 percent 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 percent to 85 percent of newly infected persons develop chronic disease and 60 percent to 70 percent of chronically infected people develop chronic liver disease; 5 percent to 20 percent develop cirrhosis and 1 percent to 5 percent die from cirrhosis or liver cancer. In 25 percent of liver cancer patients, the underlying cause is hepatitis C.
Diagnosis of acute infection is often missed because a majority of infected people have no symptoms. Common methods of antibody detection cannot differentiate between acute and chronic infection. The presence of antibodies against the hepatitis C virus indicates that a person is or has been infected. The hepatitis C virus recombinant immunoblot assay (RIBA) and hepatitis C virus RNA testing are used to confirm the diagnosis. Diagnosis of chronic infection is made when antibodies to the hepatitis C virus are present in the blood for more than six months. Similar to acute infections, diagnosis is confirmed with an additional test. Specialized tests are often used to evaluate patients for liver disease, including cirrhosis and liver cancer.
Early diagnosis can prevent health problems that may result from infection and prevent transmission to family members and other close contacts. Some countries recommend screening for people who may be at risk for infection.
- people who received blood, blood products or organs before screening for hepatitis C virus was implemented, or where screening was not yet widespread;
- current or former injecting drug users (even those who injected drugs once many years ago);
- people on long-term hemodialysis;
- healthcare workers;
- people living with HIV;
- people with abnormal liver tests or liver disease;
- infants born to infected mothers.
Hepatitis C does not always require treatment. There are six genotypes of hepatitis C and they may respond differently to treatment. Careful screening is necessary before starting the treatment to determine the most appropriate approach for the patient. Combination antiviral therapy with interferon and ribavirin has been the mainstay of hepatitis C treatment. Unfortunately, interferon is not widely available globally, it is not always well tolerated, some virus genotypes respond better to interferon than others, and many people who take interferon do not finish their treatment. This means that while hepatitis C is generally considered to be a curable disease, for many people this is not a reality. Scientific advances have led to the development of new antiviral drugs for hepatitis C, which may be more effective and better tolerated than existing therapies. Two new therapeutic agents telaprevir and boceprevir have recently been licensed in some countries. Much needs to be done to ensure that these advances lead to greater access and treatment globally.
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.
Source: World Health Organization