Occult hepatitis B is more common in people with HIV, but occult hepatitis C is rare

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Occult or hidden hepatitis B virus (HBV) infection was strongly linked to HIV-related immune suppression in a cohort of US women, but occult hepatitis C virus (HCV) infection was rare, according to a presentation on Thursday at the XVII International AIDS Conference.

Occult infection refers to persistent HBV or HCV infection without typically detectable serological markers (antigens or antibodies in the blood). Such infections can be identified by directly testing for viral genetic material (HBV DNA or HCV RNA). Due to differences in definitions and testing methods, various studies have estimated the prevalence of occult HBV at 0% to 89%, and the prevalence of occult HCV at 0% to 13%.

Lynn Taylor from Brown University and colleagues sought to assess the prevalence and explore the relationship between HIV infection and occult hepatitis. They conducted a retrospective analysis of data collected between 1993 and 2000 from 549 HIV-positive and 296 at-risk HIV-negative women in the HIV Epidemiology Research Study (HERS) cohort.


hepatitis B virus (HBV)

The hepatitis B virus can be spread through sexual contact, sharing of contaminated needles and syringes, needlestick injuries and during childbirth. Hepatitis B infection may be either short-lived and rapidly cleared in less than six months by the immune system (acute infection) or lifelong (chronic). The infection can lead to serious illnesses such as cirrhosis and liver cancer. A vaccine is available to prevent the infection.

detectable viral load

When viral load is detectable, this indicates that HIV is replicating in the body. If the person is taking HIV treatment but their viral load is detectable, the treatment is not working properly. There may still be a risk of HIV transmission to sexual partners.

deoxyribonucleic acid (DNA)

The material in the nucleus of a cell where genetic information is stored.

ribonucleic acid (RNA)

The chemical structure that carries genetic instructions for protein synthesis. Although DNA is the primary genetic material of cells, RNA is the genetic material for some viruses like HIV.


acute infection

The very first few weeks of infection, until the body has created antibodies against the infection. During acute HIV infection, HIV is highly infectious because the virus is multiplying at a very rapid rate. The symptoms of acute HIV infection can include fever, rash, chills, headache, fatigue, nausea, diarrhoea, sore throat, night sweats, appetite loss, mouth ulcers, swollen lymph nodes, muscle and joint aches – all of them symptoms of an acute inflammation (immune reaction).

Occult HBV was defined as persistent HBV DNA in the blood without detectable hepatitis B surface antigen (HBsAg), while occult HCV was defined as detectable HCV RNA with undetectable antibodies against the virus at two time-points six months apart.

Multiple time-points were used to differentiate between occult infection and either the acute stage of HBV or HCV infection—before the immune system produces enough antibodies to register on the test and before HBsAg becomes detectable—or else HBV clearance with loss of HBsAg.

At the baseline study visit, the researchers screened the women for HBsAg (detectable in 2.6%), hepatitis B core antibodies (positive in 52%), and HCV antibodies (positive in 54%).

At the second time-point, they measured HBV DNA and HCV RNA using the ultrasensitive Roche COBAS TaqMan nucleic acid assay, with a limit of detection of 15 IU/mL for HBV and 11 IU/mL for HCV. At the third time-point, they again measured both serological markers and HBV DNA and HCV RNA.

Among the women initially classified as having occult hepatitis B, some progressed to chronic infection (suggesting that the earlier visit had caught them during the acute stage) and some spontaneously cleared the virus, leaving 26 (3.2%) with persistent occult HBV by the final visit. Looking only at the HIV-positive women, however, the rate of persistent occult HBV infection was 4.7%.

All of the women with occult HBV were HIV-positive, compared with 79% of those with chronic HBV and 69% who were exposed but cleared the virus. Women with occult HBV infection were significantly more likely than chronically infected women to have a history of injection drug use (88% vs 57%) and to also be infected with HCV (88% vs 43% for HCV antibodies; 77% vs 29% for HCV RNA).

In an analysis of just the HIV-positive women, those with occult HBV had a lower CD4 cell count (205 vs 326 cells/mm3) and a higher HIV viral load (36,725 vs 4,480 copies/mL) than those who had evidence of HBV exposure but cleared the virus. Women with occult HBV were also more likely to currently inject drugs (54% vs 32%) and to drink alcohol heavily (23% vs 9%).

None of the women whose antiretroviral regimen included 3TC (lamivudine; Epivir)—which is active against HBV as well as HIV—had detectable HBV DNA.

Occult hepatitis C was found to be much less common than occult hepatitis B. Of the 33 women initially classified as having occult HCV infection, 24 developed chronic infection, eight cleared the virus, and only one had persistent occult HCV.

The researchers concluded that occult HBV infection is associated with HIV infection and may be a particular problem for women with poor control of HIV. While chronic HCV infection was common in this cohort, occult HCV infection occured rarely.