A cheat sheet from Andrew Reynolds on the most common infectious disease in the world
Hepatitis B (HBV) is a virus that infects the liver, and it is the most common infectious disease in the world. Over 2 billion people worldwide have been infected with it at some point in their life, and approximately 240 million of those are chronically infected (living with HBV). Worldwide, it leads to over 780,000 deaths every year. In the United States, an estimated 850,000 to 2.2 million people live with HBV, and about 10% of people living with HIV are co-infected with HBV.
Hepatitis B transmission
Hepatitis B is transmitted in much the same way as HIV: It’s spread when the blood, semen, vaginal fluids, and other body fluids of a person infected with HBV get into a person who is not infected or who is not protected by immunity (through vaccination or cleared infection). It is also commonly transmitted from mother to child during birth. The following activities have been associated with risk of transmission:
- Vertical (mother to child) transmission;
- Condomless sex with an infected partner;
- Sharing syringes and other drug-injection equipment (cookers, cotton, water, etc.);
- Sharing household items such as razors or toothbrushes with an infected person;
- Other blood-to-blood contact;
- Occupational exposure from needlesticks or other risks of blood-to-blood contact.
Testing for hepatitis B
Most people who become infected with HBV don’t know it because it rarely leads to signs or symptoms in the acute or chronic stages of infection. Over time, as the liver is damaged, noticeable symptoms may arise, but screening (testing) for the virus is the only way to determine if you have HBV.
Here’s who should get tested for HBV:
Persons from endemic regions of the world:
- Persons born in a country with HBV rates greater than 2%
- U.S.-born individuals who did not receive a vaccination, and whose parents were born in a country with HBV rates greater than 8%
Persons with certain medical situations or conditions:
- Women who are pregnant
- Babies born to mothers who are HBV-infected
- Individuals on hemodialysis
- People needing immunosuppressive therapy (such as chemotherapy or those receiving organ transplants)
- People with chronic HCV infection before undergoing DAA therapy
- Donors of blood, plasma, organs, tissues, or semen
- Anyone with an unexplained elevated ALT/AST
Risk-based
- People who inject drugs
- Men who have sex with men
- People living with HIV
- Household, needle-sharing (including injection equipment), or sex partners of people with chronic HBV
- People who are the sources of blood or body fluids resulting in a potential HBV exposure (such as an occupational needle stick or blood splash or sexual assault) where post exposure prophylaxis may be necessary
SOURCE: CENTERS FOR DISEASE CONTROL AND PREVENTION (cdc.gov/hepatitis)
Vaccination for hepatitis B
Hepatitis B is vaccine preventable. It is safe and highly effective in preventing HBV, successful over 95% of the time. After the first dose, the vaccine is administered one month and six months later. The vaccine remains effective the rest of your life with no need for a booster shot ever.
The following should be vaccinated against HBV:
- All infants, beginning at birth
- All children under the age of 19 years who have not been vaccinated previously
- Susceptible sex partners of hepatitis B surface antigen (HBsAg)-positive persons
- Sexually active persons who are not in a long-term, mutually monogamous relationship (e.g., more than one sex partner during the previous 6 months)
- Anyone seeking evaluation or treatment for a sexually transmitted disease
- Men who have sex with men
- Injection drug users
- Susceptible household contacts of HBsAg-positive persons
- Health care and public safety workers at risk for exposure to blood or blood-contaminated body fluids
- Anyone with end-stage renal disease, including pre-dialysis, hemodialysis, peritoneal dialysis, and home dialysis patients
- Residents and staff of facilities for developmentally disabled persons
- Travelers to regions with intermediate or high rates of endemic HBV infection
- Anyone with chronic liver disease
- Anyone living with HIV
- Unvaccinated adults with diabetes mellitus ages 19–59 years (at the discretion of clinicians for unvaccinated adults with diabetes mellitus who are aged 60 years and older)
- Anyone seeking protection from HBV infection—acknowledgment of a specific risk factor is not a requirement for vaccination
If a person already has HBV, the vaccination will offer no protection against disease progression or risk of liver disease. Sometimes, people get vaccinated without getting checked for chronic infection—ask your medical provider if you have been checked for chronic HBV infection (or, if you are someone who was exposed to the virus and then cleared it, and are thus naturally immune) before starting a vaccination schedule.