Hepatitis A (HAV) is found in faeces (stool). People become infected when faeces from an infected person enters their mouth. This may occur when food (including raw or undercooked shellfish) or water are contaminated with sewage, or when an infected person handles food without washing his/ her hands after going to the toilet, through oral-anal sex (rimming) and rarely, from blood transfusions.
A vaccine is available against HAV, but it is less effective in people with low CD4 cell counts.
Some people -- especially children -- don't feel sick at all; others have symptoms, including: nausea, vomiting, diarrhoea, fever, fatigue, rash, jaundice (yellow skin and eyes), liver pain, and dark brown urine. There is no treatment for HAV, but the symptoms can be treated. It is not a chronic infection.
A person can only be infected with HAV once. HAV goes away by itself, usually within two months
Hepatitis B (HBV) can be found in blood, semen, and vaginal fluid of infected persons. Very small amounts of HBV have been found in breast milk and saliva. A person can get hepatitis B from sharing injection or tattooing equipment, unprotected anal, vaginal or oral sex, and by sharing personal care implements (such as toothbrushes and razors). HBV can be passed from mother to child during birth.
HBV can be treated with interferon and oral antiviral drugs, such as adefovir, and telbuvidine. Some HBV drugs are also active against HIV, such as: lamivudine (3TC), emtricitibine (FTC), tenofovir and entecavir.
As with HIV, antiviral HBV treatment should not be given as monotherapy to people with coinfection. Coinfection guidelines provide detailed information on drug choices. For example, they currently recommend starting HIV treatment earlier, and including tenofovir plus either 3TC or FTC, plus at least one extra drug so that there are at least three active drugs against HIV.
Another very important caution is that once HBV treatment is started, unless the infection is completely cleared, HBV treatment should not be stopped. Removing HBV drugs can cause a serious flare of liver enzymes that can be fatal.
If HIV treatment needs to be changed, then the HIV drugs that are active against HBV need to be maintained in the next regimen.
There is less research on coinfection with other viral hepatitis infections. These include: