HBV/HIV Co-infection

A person who is infected with both the hepatitis B and the HIV viruses is said to have a HBV/HIV Co-infection. Approximately 10% of the HIV-infected population worldwide is infected with hepatitis B. This figure may approach 20% in Southeast Asia, and 5% in North America and Western Europe. Since both the hepatitis B virus and the HIV virus share similar transmission routes, it is not surprising that there is a high frequency of co-infection. Sexual activity and/or injection drug use are the most common routes of transmission of the hepatitis B virus among those also infected with HIV.

While highly active antiretroviral therapy (HAART) has dramatically improved the lives of those with HIV, the consequences of associated illnesses such as hepatitis B co-infections have become more relevant.

Conditions associated with hepatitis B and C are currently among the leading causes of hospital admission and death in the HIV-infected population. Therefore, the adequate management of hepatitis B and C is now being considered a priority in HIV-confected patients.

Since there is not a ‘cure’ at this time for hepatitis B, the main goal of treating HBV/HIV-co-infection is to stop or slow down HBV viral activity as much as possible and for as long as possible.

 

Diagnosis and Screening

All HIV-positive patients should be screened for viral hepatitis (A, B and C). Those who test positive for hepatitis B and C should seek care from a liver specialist (herpetologist or gastroenterologist) for further evaluation and management.

HBV/HIV co-infected patients who are not immune to the hepatitis A virus (lacking anti-HAV IgG antibodies) should be vaccinated to protect them from acquiring another harmful liver virus.

Management and Treatment

There are two main reasons for considering HBV therapy as a priority in HBV/HIV co-infected patients:

§First, liver disease may progress more rapidly in those patients co-infected with HBV/HIV and could lead to serious liver disease complications such as cirrhosis and liver cancer at younger ages.

§Second, there is a higher risk of developing hepatotoxicity following the initiation of antiretroviral therapy in HIV patients co-infected with HBV than in patients infected with HIV alone.

In patients infected with HBV, HIV can lead to higher rates of chronicity, decreased rates of anti-HBe and anti-HBs seroconversion, and increased viral replication, probably due to the impairment of the body’s immune responses. As a consequence, HBV/HIV co-infection is associated with increased liver fibrosis progression and increased rate of liver decompensation, cirrhosis, liver cancer or liver failure. Therefore, it is recommended to avoid the development of severe immune deficiency (defined as <200 CD4 cells/mm 3) in HBV/HIV co-infected persons.

There is no evidence that HBV affects HIV disease progression or that HBV alters the response of HIV to antiretroviral therapy (ART). However, starting ART may be associated with an increased risk of liver inflammation in co-infected individuals, as evidenced by ALT ( Alanine Aminotransferase) flares or rising liver enzymes. This may reflect both an immune response against HBV and/or drug toxicity.

Five drugs have been approved so far for the treatment of chronic hepatitis B:

§Interferon-alpha (Intron A) is given by injection several times a week for six months to a year, or sometimes longer. The drug can cause side effects such as flu-like symptoms, depression, and headaches. Approved in 1991 and available for both children and adults.

§Pegylated Interferon (Pegasys) is given by injection once a week usually for six months to a year. The drug can cause side effects such as flu-like symptoms, depression and other mental health problems. Approved May 2005 and available only for adults.

§ Lamivudine (Epivir-HBV, Zeffix, or Heptodin) is a pill that is taken once a day, with almost no side effects, for at least one year or longer. A primary concern is the possible development of hepatitis B virus mutants during and after treatment. Approved in 1998 and available for both children and adults.

§ Adefovir dipivoxil (Hepsera) is a pill taken once a day, with few side effects, for at least one year or longer. The primary concern is that kidney problems can occur while taking the drug. Approved September 2002 and available only for adults. Pediatric clinical trials are being planned.

§ Entecavir (Baraclude) is a pill taken once a day, with almost no side effects for up to one year. It is considered the most potent oral antiviral drug for chronic hepatitis B to date. Approved April 2005 and available only for adults. Pediatric clinical trials may be planned for the future.

Other drugs with anti-HBV activity such as tenofovir and emtricitabine are FDA approved for treatment of HIV infection and are frequently used in coinfected patients as anti-HBV agents.

The decision to treat chronic hepatitis B and the choice of drugs is controversial and likely to vary in different situations. Treatment recommendations include four main variables that should guide the selection of patients to be treated for HBV and of the drug of choice:

§Transaminase levels (ALT, AST)

§HBV DNA viral loads

§HBV e-Antigen presence (HBeAg)

§Liver fibrosis staging (liver biopsy)

§Ultrasound of the liver