Viral Hepatitis A and B

• Viral hepatitis is a viral infection of the liver
• The hepatitis viruses are A, B, C, D, and E
• The most relevant hepatitis viruses to dentistry are A, B, and C

Hepatitis A

• It is caused by the hepatitis A virus
• It is transmitted via the faeco-oral route, usually by consuming contaminated food and drink
• Hepatitis A is common in countries where sanitation is poor
• Symptoms usually resolve within a few months
• Treatment primarily involves relieving symptoms like pain, nausea, and itching
• Vaccination is available and recommended before traveling to high-risk countries

Hepatitis B

• Hepatitis B is caused by the hepatitis B virus
• It is common worldwide
• Hepatitis B spreads through the blood of an infected person and from infected pregnant women to their babies
• It can also spread through unprotected sex, sharing needles, needlestick injuries, and sharing razors/toothbrushes
• 5% of those infected become chronic carriers
• Some infected persons develop cirrhosis and liver cancer
• In children, it can persist for years and cause significant liver damage
• 90% of babies infected develop chronic hepatitis
• Vaccination is available for all healthcare workers
• Since 2017, it has been added to the child immunisation list
• The hepatitis B virus concentration varies in different body fluids
• The virus is high in blood, serum, and wound exudates
• The virus is moderate in semen, vaginal fluid, and saliva
• The virus is low or not detectable in urine, faeces, sweat, tears, and breast milk
• Hepatitis B is highly infectious and more easily spread than HIV
• The virus can live outside the human body for up to 7 days
• People with chronic hepatitis B can have very large amounts of the virus in their blood
• It does not spread by hugging, kissing, sneezing, coughing, or sharing eating utensils
• After a needlestick injury, the seroconversion risk is 1 in 3 if not vaccinated, compared to 1 in 300 for HIV
• The incubation period ranges from 45 to 180 days, with an average of 60 days
• The virus enters hepatocytes through the blood
• An immune response to viral antigens on the hepatocyte cell surface results in a clinical syndrome
• 5% of infected individuals become chronic carriers with a higher risk of hepatocellular carcinoma
• Hepatitis B surface antibody likely provides lifelong immunity
• Symptoms may be asymptomatic
• Symptoms, if they occur, usually appear 2 or 3 months after exposure
• Flu-like symptoms include tiredness, fever, general aches and pains, loss of appetite, nausea, diarrhoea, gastric pain, and jaundice
• Symptoms usually resolve within 1 to 3 months in acute cases, but the infection can last 6 months or more in chronic cases
• Diagnosis is through serological tests, including blood testing
• Hep B antigens are general markers of infection
• Hep B antibodies are used to document recovery and immunity to HBV infection
• The virus persists at low levels even after recovery
• Reactivation can occur spontaneously, especially if the immune system is depressed

Hepatitis B Treatment

• Emergency treatment following exposure includes a Hep B vaccine and immunoglobulin
• Acute cases are treated with rest, analgesia, and symptom relief, such as metoclopromide for nausea
• Chronic cases are treated with peginterferon alfa-2a to stimulate the immune system, given by weekly injection, potentially causing flu-like side effects
• Antiviral medications such as tenofovir or entecavir, can cause side effects such as nausea, vomiting, and dizziness
• Preventative measures involve avoiding unprotected sex, vaccinating partners, avoiding sharing needles, razors and toothbrushes
• Other preventative measures include eating a healthy, balanced diet and avoiding alcohol

Hepatitis B Prevention

• Vaccination is recommended for those at increased risk of HBV infection
• A vaccination schedule includes three doses at months 0, 1, and 6
• An immune response can be observed: 50% after one dose and 95% after three doses
• Protection lasts >15 years and is dependent on initial antibody response
• Hepatitis B immunoglobulin is given to protect people exposed to Hep B, and is most effective within 48 hours of contact
• Other methods include screening blood donors and taking precautions with blood and body fluids
• Hepatitis B carries a definite mortality risk
• Healthcare professionals are potentially at risk and should be immunised
• All patients should be treated as potential carriers of the disease via universal precautions
• Always wear PPE, as saliva to the eye is a potential route of infection
• Always avoid needlestick injuries and report them, should they occur

Hepatitis C

• Hepatitis C is a single-stranded RNA virus
• Pathogenesis, symptoms, and transmission routes are the same as Hepatitis B
• Occupational transmission can occur through needlestick injuries
• Transmission from blood splash to the eye has been reported, so follow universal precautions
• There is no vaccine available for Hepatitis C
• Long-term complications include cirrhosis, liver failure, and liver cancer
• Chronic cases can be treated with direct acting anti-viral medication for 8-12 weeks eg, ribavarin, simeprevir, sofosbuvir, etc
• Side effects can include nausea and insomnia
• Lifestyle changes include ceasing alcohol consumption and smoking, eating a healthy diet, partaking in more exercise, and not sharing razors or needles

Hepatitis D

• Requires the presence of Hepatitis B to infect
• Chronic infections cause liver scarring, cirrhosis, and cancer
• Hepatitis D is spread with contact with bodily fluids
• It is mainly seen in IV drug users
• A vaccine is available

Hepatitis E

• Transmitted by the faeco-oral route
• Hepatitis E is similar to Hep A
• There is no vaccine available