Viremic hepatitis C infection was frequent among individuals in sub-Saharan Africa who were serologically positive for the virus, according to new data published in Clinical Infectious Diseases.
“The … results highlight the importance of stringent diagnostic strategies for future studies of HCV in sub-Saharan Africa,” the researchers wrote. “Past studies have suggested a high rate of false-positive serologic results and low levels of detectable viremia in studies from sub-Saharan Africa.”
Jennifer E. Layden, MD, PhD, of the department of medicine at Loyola University Medical Center, and colleagues conducted a prospective study of 363 past blood donors in Ghana to evaluate the incidence of active HCV infection and risk factors for infection. According to serologic testing at time of donation, 180 of the donors were positive on rapid screen assay (RSA) for HCV, and 183 were negative. The participants underwent additional blood testing and answered a questionnaire about risk factors.
The researchers found that 87 individuals had evidence of HCV infection. Among those, 82 individuals were RSA-positive and had a Signal to Cut-off (S/C) ratio of at least 11 on chemiluminescent immunoassay (CIA), which is the S/C ratio criteria established by the CDC for this assay. Of those with sufficient samples who underwent viral load testing, 66 had detectable viremia, and nine did not.
If these criteria (RSA positivity and CIA S/C ratio of at least 11) were used to define HCV infection, then 88% of the patients had an active infection. If less stringent criteria were used (ie, RSA positivity and CIA S/C ratio greater than 1), however, 74.4% of the patients had active infection. If considering only RSA positivity, the rate of active infection would be only 42.2%.
In multivariable analyses, tribal region of origin was significantly associated with HCV infection. Individuals from the northern region were 6.6 times more likely to be infected, and individuals from the upper region were 18.7 times more likely to be infected. Other risk factors included traditional circumcision, no circumcision and hepatitis B virus seropositivity.
“These rates of active infection fall within the range reported in the US, especially for black Americans, who have a higher rate of chronic infection than Caucasians and Hispanics,” the researchers wrote. “However, they are in sharp contrast to prior studies in sub-Saharan Africa. Future studies are warranted to characterize the population-level epidemiology of HCV across sub-Saharan Africa using standardized diagnostic criteria, and to refine our knowledge of region-specific HCV risk factors.”
Disclosure: The researchers report no relevant financial disclosures.