HIV and Hepatitis B dilemma

HIV and Hepatitis B delimma

HIV and Hepatitis B dilemma – Human Immunodeficiency Virus (HIV) and Hepatitis B Virus (HBV) co-infection is common due to their similarities and shared modes of transmission.

In addition to this similarity, the use of reverse transcriptase enzyme, their ability to mutate their genome to resist some antivirals therapy and the tendency to develop chronic infections are some similar characteristics possessed by the two viruses.

In 2010, people worldwide living with HIV was estimated to be 34.0 million. Recently, the latest report by the United Nations program on Acquired Immuno-Deficient Syndrome (AIDS) revealed that about 36.7 million (30 million – 42.9 million) people globally are living with Human Immuno-Deficiency Virus (HIV).

Out of this number, 20.9 million people have been put on antiretroviral therapy and 1.8 million (1.6 million – 2.1 million) new cases are reported every year.

Out of the total number of persons living with HIV worldwide, about 10% are estimated to have chronic forms of HBV infection. HBV/HIV co-infection accelerates disease progression. For instance, liver cirrhosis, liver fibrosis, end-stage liver disease, hepatocellular carcinoma (HCC) and mortality arising from HBV are accelerated with individuals with co-infection. Nikolopoulos et al (2009), demonstrated a 36% increase in mortality of persons with the HBV/HIV co-infection when a total of 12,382 patients were recruited in Greece.

Hepatitis B (HBV) infection is a major public health concern worldwide. Each year about 600,000 lives are lost due to acute or chronic HBV infection. According to a report by the World Health Organisation (WHO), out of 2 billion persons infected with HBV, 350 million accounts for the chronic form of the disease. Chronic HBV infection has become the second biggest killer after tuberculosis. Subsequently, persons infected with HIV are found to be six (6) times more likely to develop chronic HBV infection than HIV negative counterparts.

The specific mechanisms in which HBV and HIV interact are not clearly understood, however, over the years, HIV/HBV co-infection has been known to facilitate and promote higher rates of HBV replication, reduce the resolution of the HBV infection and higher risk of reactivation of the HBV infection.

It should be noted that HIV individuals who contact HBV infection are less likely to eliminate it compared to uninfected Person Living with HIV (PLHIV) or AIDS patients. HBV/HIV co-infection presents a great challenge to healthcare providers globally. Administering antiretroviral therapy (ART) could be very challenging in individuals with co-infection.

HIV and Hepatitis B dilemma

The case is worse when HIV infected individuals do not respond or are less responsive to the therapy. There is a higher risk of developing hepatotoxicity and drug-drug interactions under ART.

When treatment options are unavailable for patients with HBV/HIV co-infection, there is an increased HBV DNA (deoxyribonucleic acid) viral levels and prolong or longer duration of viremia. This also results in lower levels of transaminase. These clinical outcomes are usually different from individuals infected with only HBV. Vertical and horizontal transmission is also increased due to prolong the duration of viremia in areas where there is a high prevalence of HBV.

The prevalence of occult HBV infection ranges from <1% to 89.5% in HIV-1 in persons with co-infections. The presence of HBV DNA in the serum of patients without the presence of HBsAg (Hepatitis B surface Antigen) is termed as occult HBV infection. There are several reasons accounting for the wide variation in terms of prevalence.

Possible reasons include intermittent HBV replication not captured by isolated samples, different quantification methods of HBV replication, different quantification methods have different sensitivities and inconsistencies in reporting ART regimen. It should be noted that the clinical relevance of occult HBV in HIV- 1 infected person is not clear.

Co-infected (HIV/HBV) individuals with a high HBV replication should be placed on the combination ART even if they do not meet the criteria. As stated earlier, in the context of HIV infection, HBV infection progresses faster and rapidly to cirrhosis with reduced response to HBV treatment regimens as immunodeficiency progresses. The goals for treating HBV in co-infected individuals are the same for mono-infected HBV individuals namely normalization of the transaminase levels (ALT), improve liver histology findings and the overall to decrease viral HBV DNA.

Replication activity of HBV requires the use of reverse transcriptase-polymerase. The activity of the reverse transcriptase enzyme lacks proofreading activity, as a result, HBV exhibit a mutation rate of >10- fold which is greater than any other DNA viruses.

HIV and Hepatitis B dilemma

The characteristic of the HBV virus closely resembles HIV retrovirus in this regard. In the United States of America (USA), five drugs have been approved by the Food and Drugs Authority (FDA) to be used in the management of persons with the co-infections (IFN- a- 2b, lamivudine, adefovir dipivoxil, entecavir, and pegylated IFN- a- 2b). Tenofovir and emtricitabine have also been proven to be very infective against the treatment of HBV infection though have not been licensed by the USA.

The case is however different in Ghana, treatment is individualized according to the patient status. The patient status is determined by the degree of liver damage, the rate of HBV DNA replication and whether or not the said patient is on Highly Active Antiretroviral Therapy (HAART) or due to start.

The preferred drugs used in the management of HBV/HIV co-infection in Ghana are efavirenz, lamivudine, and tenofovir. Emtricitabine is used as an alternative.

To minimize the selection of drug-resistant HIV and/or HBV, the management of both infection must be carefully coordinated. In HIV/HBV co-infected patients, antiretrovirals should be selected and monitored to minimize the risk of HBV and HIV resistance. Therefore, the focus of this research is to assess the management of HBV/HIV co-infected patients on ART.

Wright Amesimeku

Ghana Health News