Hepatitis B virus (HBV) infection still stands as a major global public health problem, especially in developing countries where the prevalence and morbidity rates are relatively high. World Health Organization (WHO) estimated that about 254 million people globally were living with chronic HBV infection in 2022, and most of these cases were found in low-and middle income countries. ¹ Moreover, HBV is a leading cause of cirrhosis of the liver and hepatocellular carcinoma (HCC), which contribute greatly to mortality as well as morbidity related to the liver. ^{2– 6} There is a need for a comprehensive understanding of its epidemiology and management.

Quantification of HBV viral load is an important factor in the clinical management of HBV infection, helping in making decisions concerning eligibility for therapy and antiviral prophylaxis, and informing about disease development and possibility of transmission. ^{7– 10} It involves measuring the concentration of HBV DNA within a person’s blood, which mirrors viral replication activity. Higher levels are associated with more liver inflammation, fibrosis progress as well as greater chances to develop HCC. ¹¹ Assessing of the viral load levels is useful not only for managing patients but also for tracking public health response activities. When more individuals have high viral loads, it means they are actively transmitting the virus leading to possibilities of outbreaks thus making targeted public health responses necessary. ¹²

Within Sudan, Gezira State located centrally has been identified as one such region with significant burden of HBV infection. Studies conducted in Gezira State indicate that chronic HBV infection is highly prevalent and together with its long-term complications such as liver cirrhosis and hepatocellular carcinoma represents a significant public health challenge. ¹³

Gezira State is one of Sudan’s most populous regions in Sudan. It includes densely populated areas and a large number of people who are going from rural to urban areas that support HBV transmission. ¹⁴ The state is distinguished by the presence of large-scale national irrigation schemes, a fact that rendered its epidemiological profile for HBV transmission a complex one. Migration patterns, the presence of diverse demographic groups resembling rural-urban disparities, difficulties in healthcare access, and fragile socioeconomic settings are some of the factors that influence the spread and management of HBV in this state and contribute further complexity to HBV epidemiology forcing disease control measures to be specifically targeted rather than universal.

There are limited data on the levels of HBV viral loads in patients of Gezira State despite their significance. This paucity of knowledge is very crucial as it limits the development of effective public health policies and clinical interventions that are tailored to fit into local epidemiology. Besides, there is a necessity to comprehend demographic and clinical factors that associate with viral load to identify populations at risk and optimize HBV resource allocation.

The aim of this study was to quantify HBV viral load among patients with HBV infection in Gezira State; and to analyze the distribution of viral loads among different demographic groups. It also attempted to identify possible predictors of high viral load which can be used for risk stratification and tailored therapeutic strategies.

Of the 100 hepatitis B patients included in this study, 40 (40%) were female and 60 (60%) were male ( Table 1). Ages of participants ranged between 16 years and 70 years (mean 40 years). Viral load values ranged from 15 IU/ml to 35,474,488 IU/ml. The mean HBV viral load of all the 100 participants was 886,363 IU/ml (SD±421,295). Comparison of the mean viral loads by gender revealed a significant difference between the two: mean viral load of males alone was 1,122,899 IU/ml) (SD± 510,342), while that of the female category was 531,559 IU/ml (SD± 233,208) (p < 0.0001). Distribution of viral load ranges among patients according to gender revealed that the highest viral load range (>1,000,000 IU/ml) was detected in five males (5%) and three females (3%), with total 8 (8%) of the study population. The lowest viral load range (0-100 IU/ml) was detected in 15 males (15%) and nine females (9%) with total 24 (24%) of study population. Table 1 shows distribution of all ranges by gender.

When categorizing the viral load values into ranges, the largest proportion of patients (31%, n=31) fell into the 101-1,000 IU/ml group (second lowest), with almost equal male: female ratio ( Table 1; Figure 2). However numbers and percentages of male patients surpassed the corresponding female ones in all the other groups including the entire ranges of highest viral load ( Figure 3).

The viral load was also quantified in all age groups. Difference within all groups was not statistically significant (p=0.939). The highest viral load (> 1.000.000 IU/ml) was detected in 0 (0%) in age group (0 - 20) years, 1 (1%) in age group 20 - 29 years, 1 (1%) in age group (30 - 39) years, 4 (4%) in age group (40 - 49) years, 1 (1%) in age group (50-59) years and 1 (1%) in age > 60 years with total 8 (8%) of the study population. The lowest viral load range (0-100) IU/ml was detected in 3 (3%) in age group (0 - 20 years), 4 (4%) in age group (20-29) years, 7 (7%) in age group (30-39) years, 5 (5%) in age group (40-49) years, 5 (5%) in age group (50- 59) years and 0 (0%) in age group > 60 years with total 24 (24%) of the study population. Table 2 and Figure 4 show distribution of all viral load ranges among all age groups.

The study elicited the significance of quantifying the viral load of HBV patients and came up with important data regarding the situation of HBV infection in Gezira state. The mean viral load in participants amounted to an alarmingly high level of 886,363 IU/ml (SD±421,295); and while the WHO recommendations of 2024 ¹⁰ advise commencing treatment at HBV DNA >2000 IU/ml (in addition to an ALT level above the upper limit of normal), over third of the study participants (37%, n=37) had VL above this limit This warrants more attention from public health authorities in Gezira to take actions including incorporation of viral load quantitative testing in survey and management of HBV infection; and revision of treatment plans. The findings in our study were consistent with those of a research conducted in Sudan, ¹⁶ which reported closely similar variations in viral loads among patients in the region of Khartoum State.

The average viral load was significantly higher in our male patients than in female patients (p<0.0001). This result is in-line with several research conclusions worldwide that identified this gender disparity. A study from Taiwan found males had higher HBV viral loads than females. ¹⁷ Similarly a study from West Africa revealed a significant association between hepatitis B viral load and gender; the median viral load was higher in men than in women and males were more likely to have a higher viral load than females. ¹⁸ Another study recognized this disparity and offered an explanation that direct and indirect factors play a role in this difference. A direct factor is by the regulation of viral gene expression; the indirect by host immune responses modulation. ¹⁹

While the study observed a wide variation in distribution of viral load among the different age groups but it did not discover a statistically significant correlation between age and HBV viral load (p=0.939). Unlike the issue of correlation of gender with HBV load which harvested many confirmations in published research, influence of age on HBV viral load exhibited widely conflicting results across studies. Several studies reached conclusions like ours and did not establish a significant association of age with HBV viral load. ^{20– 23} On another hand, one would find several other studies on different cohorts of HBV patients, including HCC patients, ethnic groups, and people with co-infections or special conditions … etc. that documented significant correlation between age and HBV viral load. ^{24– 28} However, despite the agreement of these studies on the significant influence of age on viral load, but notably they produced diverse results about which age group had the increasing viral load. While a study may report viral load increases with age, ²⁶ another may conversely state that higher viral loads were predominant in much younger ages and decrease with old age. ¹⁸ Multiple studies on similar cohorts in different geographical, environmental and social situations are recommended to clarify these disparities.

The study realized the importance of quantitative testing of HBV DNA in HBV patients in Gezira state. The high mean HBV viral load of the studied sample (886,363 IU/ml), calls for further actions by the concerned public health authorities in Gezira state. The study found the mean viral load to be significantly higher in male gender than in females (p<0.0001). Regarding age, the study did not find a statistically significant correlation between viral load and age in the studied sample. Nevertheless the study observed the presence of wide variation in viral load values amongst different age groups.

Gender-specific treatment strategies and personalized care approaches are recommended in order to reduce the risk of severe liver disease and manage HBV effectively and in consistency with international guidelines. The study recommends and encourages further comprehensive and detailed research in different aspects of quantification of HBV viral load within Gezira State specifically and all other states of Sudan as general.