Hepatitis B and HIV co-infection

HBV is 100 times more infectious than HIV and 10 times more infectious than HCV6. An estimated two billion people around the world are infected with the Hepatitis B virus (HBV).

Of the two billion, about 400 million people develop chronic HB infection, and possibly as many as six million people are co-infected with HIV.

The African region has one of the highest HBV endemicity with an estimated 6.1% infection rate among adults. Due to their shared risk of transmission, people with HIV are at high risk (40%) acquiring HBV co-infection compared to their HIV-negative counterparts, increasing their risk of morbidity and mortality. In South Africa, HBV- HIV co-infection is estimated to be between 2% and 30.6%1,2,3.

The virus is most commonly transmitted from mother to child during birth and delivery, as well as through contact with blood or other body fluids during sex with an infected partner, unsafe injections or exposures to sharp instruments.

Like HIV, HBV transmission is predominantly spread vertically (mother to neonate). It can also be spread horizontally (mother-to-child or child-to-child) as a result of exposure of abraded skin, cuts, minor open wounds, or mucosal surfaces to blood or body fluids containing HBV from affected patients. HB can also be sexually transmitted, particularly in unvaccinated men who have sex with men and heterosexual persons with multiple sex partners or have contact with sex workers3.

Chronic HBV infection

Infection in adulthood leads to chronic HB in less than 5% of cases, whereas infection in infancy and early childhood leads to chronic HB in about 95% of cases. The good news is that worldwide, infection rates among children under five years of age with chronic HBV dropped to just under 1% in 2019, 4% down from the pre-vaccine era (1980-2000s)3.

Chronic HBV is the leading cause of liver cirrhosis, and hepatocellular carcinoma (HCC), the main primary malignant tumour of the liver. Cirrhosis and HCC cause more than 1.34 million deaths per year, according to the World Health Organization (WHO) 3.

Prevention of hepatitis a global concern

If effective prevention strategies are not put in place, the WHO estimates that chronic HBV will result in 17 million deaths by 2030. In 2011, the WHO passed a resolution recognising viral hepatitis as a global health concern3,4.

In October 2015, the WHO released its first official strategy for the control of viral hepatitis, which aims to significantly reduce the considerable morbidity and mortality found in individuals with chronic HBV infections by the year 2030. The strategy includes ambitious targets of a 90% reduction in the incidence of viral hepatitis, an 80% treatment uptake by eligible patients, and a 65% reduction in mortality4.

The hepatitis B vaccine is the mainstay of prevention. The SAHCS guidelines state that all eligible children and adults should be vaccinated. The WHO recommends that all infants receive the hepatitis B vaccine as soon as possible after birth, preferably within 24 hours – followed by two or three doses of hepatitis B vaccine at least four weeks apart to complete the series. Timely birth dose is an effective measure to reduce transmission from mother-to-child3,6.

The vaccine has been available since the 1980s. It is extremely effective and is the first vaccine to protect against cancer by reducing the incidence of HCC in highly endemic areas by 75%. In children, its effectiveness exceeds 90%. Complete vaccination confers a protection of 20 years, possibly even for life. It is important to note that the vaccine is not effective against an already established infection nor against escape mutants at vaccination3.

How is it treated?

In addition to infant vaccination, the WHO recommends the use of antiviral prophylaxis for the prevention of HBV transmission from mother-to-child.

According to the Department of Health’s viral hepatitis guidelines, the goals of treatment are to prevent HIV/ HBV co-infection, long-term complications of chronic HBV, HBV reactivation in the setting of immunosuppression/biologicals/ chemotherapy, and to ensure HBV suppression in acute liver failure7.

In people living with HIV, HBV co-infection increases the risk of liver-related disease progression and continuous non-AIDS defining morbidity1,6.

It is important to note that HBV infection cannot be eradicated completely with currently available therapies.

References

  1. Weldemhret Epidemiology and Challenges of HBV/HIV Co-Infection Amongst HIV-Infected Patients in Endemic Areas: Review. HIV/AIDS – Research and Palliative Care, 2021.
  2. Hepatitis B. https://www.who.int/news-room/fact- sheets/detail/hepatitis-b
  3. King J and Hagemeister DT. Hepatitis B co-infection in HIV-infected patients receiving antiretroviral therapy at the TC Newman Antiretroviral Treatment Clinic in Paarl, Western Cape. S Afr J HIV Med, 2016.
  4. Nguyen MH, Wong G, Gane E, et Hepatitis B Virus: Advances in Prevention, Diagnosis, and Therapy. Clin Microbiol Rev, 2020.
  5. Kramvis A. Molecular characteristics and clinical relevance of African genotypes and subgenotypes of hepatitis B SAMJ Research, 2018.
  6. Bekker L-G, Brown B, Joseph-Davey D, et al. Southern African guidelines on the safe, easy and effective use of pre-exposure prophylaxis: Southern African Journal of HIV Medicine, 2020.
  7. National Department of 2019 ART Clinical Guidelines for the Management of HIV in Adults, Pregnancy, Adolescents, Children, Infants and Neonates. Updated: March 2020.