Hepatitis b is a viral infection that affects the liver. It’s most often spread through contact with an infected person’s blood or body fluids, and can cause both acute and chronic hepatitis. It can also be passed on from mother to baby at birth. It can lead to serious liver disease, including cirrhosis and liver cancer, if left untreated. The virus can also cause other symptoms, such as fatigue and a sore, tender abdomen. Hepatitis b is less common than hepatitis a, but it is still a leading cause of chronic hepatitis worldwide. The vaccine can prevent hepatitis b, and regular blood tests should be used to monitor for the disease in those at risk.
Hepatitis B virus (HBV) is a member of the pararetrovirus family and, like other retroviruses, replicates by binding to host cellular receptors and converting double-stranded DNA into cccDNA that serves as a template for RNA replication. Once the RNA is synthesized, it is converted into viral proteins that are released into the cell, where they initiate the virus replication process. The cccDNA is then passed to new cells, where it can infect them as well.
Most people who get hepatitis B do not have any symptoms, and some have mild ones. It is rare for hepatitis B to become a life-threatening illness. Almost everyone who gets hepatitis B recovers from the acute infection within six months, but it can become a long-term or chronic infection. If it is chronic, most people who are infected will have the disease for the rest of their lives.
Infection is most common among those who inject drugs, but it can occur in anyone who is exposed to contaminated blood and body fluids. It is also commonly spread through needlestick injuries from acupuncture, tattooing, and other forms of body art; sharing needles or syringes for drug injection; and through sexual transmission. Hepatitis B spreads from one person to another through contaminated blood and body fluids, particularly saliva and menstrual, vaginal and seminal fluids. HBV is more common in infants and children who are born to mothers with the infection, and the vast majority of cases of hepatitis B that develop in childhood or infancy become chronic.
Unlike some viruses, hepatitis B is not easily spread through saliva, which means you can’t catch it from someone who coughs or sneezes on you, or by eating food or drink that has been prepared with contaminated hands or utensils. However, the virus can live on surfaces outside the body for at least seven days, so it is possible to get hepatitis B from using medical instruments that aren’t sterilized or by sharing razors and toothbrushes. The virus can also be transmitted through a transfusion or by using a dirty catheter. Vaccination against hepatitis B is effective, and the vaccine is available and covered by most health insurance plans. It is recommended that you be vaccinated before you travel to countries where the disease is more common.