About 8% of people tested through a community-based
screening program in the Gambia have hepatitis B, and about 8% of these have
advanced liver disease and meet European criteria for antiviral therapy,
according to a report presented at the 7th International AIDS Society Conference on HIV Pathogenesis, Treatment and
Prevention (IAS 2013) this month in Kuala Lumpur. None of the participants were aware of
their infection, however, and access to care and treatment remains
Maud Lemoine with the Medical Research Council's Gambia Unit reported findings from PROLIFICA –
Prevention of Liver Fibrosis and Liver Cancer in Africa – the first programme aimed at
testing, assessing and treating chronic hepatitis B in West Africa. Funded by
the European Commission, the five-year project aims to enrol 13,000 people in
the Gambia, Nigeria and Senegal. The report at IAS covered preliminary findings
from the Gambia.
Hepatitis B virus (HBV) infection is endemic in sub-Saharan
Africa and liver cancer – one of the potential consequences of untreated infection – is common, Lemoine noted as background. Hepatocellular
carcinoma, a type of primary liver cancer, is the leading cancer among men and
the second among women in West Africa, with at least half attributable to HBV. But
screening and management of liver disease are 'sorely lacking'.
A non-invasive test, used instead of a biopsy, to measure the stiffness
or elasticity of the liver using an ultrasound probe.
enzyme that can be measured in a blood sample that indicates the health of the
The PROLIFICA project offered point-of-care HBV
testing to individuals age 30 and older, after providing community education
about hepatitis B and liver cancer. Many people under 30 have been vaccinated
against HBV through child immunisation efforts, Lemoine explained.
Between December 2011 and March 2013, a total of 4597
individuals from randomly selected rural and urban areas in the Gambia were
tested for HBV. A total of 379 tested positive, for a prevalence of 8.3%. Almost
all were hepatitis B "e" antigen (HBeAg) negative. None were
previously aware of their status.
People who tested positive for HBV were offered further
evaluation with clinical examinations, laboratory analyses including
transaminase liver enzyme levels, tests for other infections, liver ultrasound and
transient elastography (FibroScan). Those
suspected of having advanced liver disease received liver biopsies, and those
with confirmed advanced disease were offered treatment with tenofovir (Viread).
Among screened individuals who tested HBV positive,
318 – more than 80% – visited the PROLIFICA liver clinic for further
evaluation. They were joined by 240 individuals from an historical
community-based cohort of people with HBV from the villages of Keneba and
Manduar, for a total study population of 558. A randomly selected 30% of people
who tested HBV negative were asked to act as a control group (n = 272).
A majority of participants with HBV were women and the
average age was approximately 40 years. Lemoine explained that women were not
more likely than men to have hepatitis B, but more frequently sought further
evaluation and care.
Among the evaluated population with HBV, 2.2% had HIV co-infection, compared with 4% among the HBV-uninfected control
participants. In addition, 1.5% had hepatitis delta and 1% had hepatitis C virus (HCV) co-infection.
Further evaluation revealed that 13% of people with
HBV had elevated transaminase levels, indicating active liver inflammation. FibroScan testing showed that 11% had a
liver stiffness measurement above 7.2 kiloPascals (kPa), equivalent to Metavir
stage F2, or moderate fibrosis. Of these, 14 people, or 2.5%, had confirmed
advanced liver disease.
Six people (1%) had liver lesions detected by
ultrasound, including one person with hepatocellular carcinoma who died three
months later. Among 74 people who underwent liver biopsies, 25% were found to
have significant fibrosis (stage F2 or higher) and the same proportion had significant
histological activity (stage A2 or higher).
Among the HBV negative control group, in contrast, 5%
had elevated transaminase levels, 6% had liver stiffness scores above 7.2 kPa,
less than 1% had confirmed advanced liver disease and 5% had liver lesions – all benign – according to ultrasound.
Most of the HBV-positive participants (72%) were
determined to be asymptomatic HBeAg negative chronic carriers with normal liver
enzyme levels, low HBV viral load and no significant fibrosis. In addition, 26%
were active chronic carriers with elevated transaminases or high HBV viral load
(>2000 IU/mL). Finally, 2% were HBeAg positive 'immunetolerant' carriers
with normal liver enzymes and no fibrosis.
Overall, 8.2% of study participants met European criteria
for antiviral treatment according to 2009 EASL guidelines. A majority of this
group (64%) were men, with a mean age of 38 years. The mean liver stiffness
score was 7.4 kPa and among those with biopsies, nearly three-quarters had at
least stage F2 fibrosis.
"In the Gambia, the preliminary data from the
PROLIFICA project suggest that at the community level, 8.3% of the population >30
years is infected with HBV without being aware of their HBV status," the
researchers concluded. "Applying the 2009 EASL criteria, 8.2% of
HBV-infected subjects are eligible for antiviral therapy."
Based on these findings, the PROLIFICA team urged that
tenofovir at generic cost should be made available not only for people with HIV
in Africa, but also for HBV mono-infected individuals.