Factors Associated with the Seroprevalence of Hepatitis B Virus Infection among Military Personnel in the Bouaké Region (Côte d’Ivoire) ()
1. Introduction
Hepatitis B virus (HBV) remains a major public health issue worldwide. In 2022, the World Health Organization (WHO) estimated that approximately 254 million people were living with chronic hepatitis B, with 1.2 million new infections each year. This infection causes nearly 1.1 million annual deaths, mainly due to severe complications such as cirrhosis or hepatocellular carcinoma [1].
Côte d’Ivoire is classified as a high-endemicity zone, with an estimated prevalence between 8% and 12% [2]-[4]. Military personnel are among the at-risk groups due to their frequent mobility, young age (often sexually active), and involvement in potentially risky missions (e.g., caring for the wounded, exposure to blood, transfusions, etc.).
Despite this high exposure, few studies have focused on the epidemiology of HBV in this specific population in Côte d’Ivoire [5]. This study, therefore, aims to determine the seroprevalence of hepatitis B virus infection and to identify associated risk factors among members of the National Armed Forces of Côte d’Ivoire stationed in the Bouaké region.
2. Patients and Methods
This was a single-center, cross-sectional, descriptive, and analytical study. It was conducted from September 2021 to March 2022 at the National School for Active Non-Commissioned Officers (ENSOA) in Bouaké. Included were all military or gendarmerie personnel stationed in a unit of the Armed Forces of Côte d’Ivoire in Bouaké who gave informed consent. Civilian personnel and non-consenting military personnel were excluded.
2.1. Study Protocol
This study benefited from the work of the PNLHVi (National Program for the Fight Against Viral Hepatitis) as part of a hepatitis B awareness and screening campaign, from which we inherited the data. The study took place in two phases (clinical and biological).
Clinical phase: Questionnaires were used to collect information on socioprofessional characteristics (age, sex, unit, qualifications, years of service, number of missions inside and outside the country), medical history (transfusions, unprotected sex), and hepatitis B vaccination status. A person was considered vaccinated if they had received three doses of the vaccine.
Biological phase: A 5 to 8 ml venous blood sample was taken and stored in a dry tube, then transported in a cooler at 15˚C - 20˚C to the Diagnostic and Research Center for AIDS and other infectious diseases at CHU Treichville. The samples were centrifuged at 3000 rpm for 10 minutes. HBs antigen and total anti-HBc antibodies were detected using ECL sandwich technique with the COBAS system, and samples were aliquoted for storage (Serotec) pending result validation.
2.2. Statistics
The data collected from the survey forms were recorded and then analyzed using SPSS software version 20.0. A comparison of the observed proportions was performed using either the Chi-square test or Fisher’s exact test; the p-value (significance threshold) was considered significant if it was less than 0.05.
2.3. Ethics
The study received ethical approval from the appropriate committee and from commanders of military units in Bouaké. The study protocol was explained to military personnel, and oral informed consent was obtained. The questionnaire was completed anonymously.
3. Results
The study involved 227 military personnel from the Bouaké military region. The average age was 32.2 years (range: 20 to 54). The participants included 10 enlisted soldiers, 214 non-commissioned officers, and 3 officers. The sex ratio was 7.4. Soldiers with less than 10 years of experience were most represented (65.6%), and 79% were single. Eleven participants (4.85%) reported full vaccination. HBs antigen was positive in 12 soldiers (5.29%), and anti-HBc antibodies were positive in 43.6% of cases (Table 1).
Table 1. General characteristics of military personnel.
|
Number (n) |
Percentage (%) |
Sex |
|
|
Male |
200 |
88.1 |
Female |
27 |
11.9 |
Age Group |
|
|
[20 - 30 years[ |
116 |
51.1 |
[30 - 40 years[ |
63 |
27.7 |
40 years and over |
48 |
21,2 |
Professional Category |
|
|
Non-commissioned officers |
214 |
94.3 |
Enlisted personnel |
10 |
4.4 |
Officer |
3 |
1.3 |
Professional Experience |
|
|
<10 ans |
149 |
65.6 |
[10 - 20] years |
69 |
30.4 |
>20 years |
9 |
4.0 |
Marital Status |
|
|
Married |
48 |
21.1 |
Single |
179 |
78.9 |
Reported Being Vaccinated Against HBV |
|
|
Yes |
11 |
4.85 |
No |
216 |
95.15 |
HBsAg Positive |
12 |
5.29 |
Total anti-HBc Antibodies Positive |
99 |
43.61 |
Significant factors associated with HBsAg positivity included age over 30 (p = 0.032), being single (p = 0.027), more than 10 years of service, and having completed missions inside the country (Table 2).
Table 2. Factors associated with HBsAg positivity among military personnel.
|
HBsAg
Positive |
HBsAg
Negative |
p |
Sex |
|
|
|
Male |
11 |
189 |
1 |
Female |
1 |
26 |
|
Age |
|
|
|
Age< 30 years |
1 |
118 |
0.002 |
Age ≥ 30 years |
11 |
97 |
|
Marital Status |
|
|
|
Married |
3 |
47 |
0.017 |
Single |
36 |
141 |
|
Professional Experience |
|
|
|
<10 years |
3 |
135 |
0.007 |
≥10 years |
9 |
78 |
|
Subjects declared vaccinated against hepatitis B |
|
|
|
Yes |
12 |
190 |
0.43 |
No |
0 |
25 |
|
Risky Sexual Behavior |
|
|
|
Yes |
1 |
11 |
0.48 |
No |
11 |
204 |
|
Mission Performed |
|
|
|
Yes |
10 |
104 |
0.018 |
No |
2 |
111 |
|
4. Discussion
This study aimed to evaluate HBV prevalence and associated risk factors in a military population in Côte d’Ivoire. Military personnel are typically considered at-risk for viral infections due to mobility, potential blood exposure, and risky sexual behavior. Our study population consisted mainly of young men, similar to findings from studies conducted in Benin and Senegal [6] [7].
Vaccination coverage remains low: only 4.85% reported receiving the full three-dose vaccine regimen. This confirms results from Diop in Senegal and Assi in Côte d’Ivoire, who also reported low vaccination rates [5] [6]. In Côte d’Ivoire, the lack of a national policy for vaccinating at-risk personnel likely explains this low coverage. Consequently, hepatitis B vaccination in high-risk professions depends on individual initiative [5]. In countries with such policies, like the United States, more than 65% of firefighters are vaccinated against hepatitis B [8]. Approximately 40% of participants had anti-HBc antibodies, indicating prior exposure to HBV, as is common in most African high-endemic countries [9] [10].
The 5.29% HBsAg prevalence found in our study is similar to that of other occupational categories in Côte d’Ivoire [11], the region [12], and some developing countries [13] [14]. However, it is lower than previously reported rates among Ivorian soldiers in 2008 and 2012 (15%) [5] [15]. This may be due to the younger age of the population studied, who could have benefited from infant vaccination introduced in 2001 [16]. Indeed, 52.4% of the soldiers in our study were under 30. Further studies could assess protective antibodies (anti-HBs) to evaluate the real effect of vaccination in this group.
Other factors significantly associated with HBsAg positivity were over 10 years of service, participation in missions, and being single. These findings show that the military profession remains at risk for HBV infection. Risky behaviors like unprotected sex, sharing sharp objects, and blood transfusion were also linked to HBV infection in other regional studies [6] [7] [17] [18].
5. Study Limitations
This study had some limitations. Only soldiers who gave informed consent were included, possibly introducing selection bias. As a cross-sectional study, it cannot establish causality between risk factors and HBV infection. Furthermore, only a univariate analysis was conducted, which did not account for potential confounding factors. Nevertheless, it provides an overview of hepatitis B among soldiers in Bouaké and highlights determinants that may contribute to infection.
6. Conclusion
Hepatitis B is relatively frequent in the Bouaké military region, with a prevalence of 5.23%. It predominantly affects soldiers over 30, single, with more than 10 years of service, and who have completed missions within the country. These factors should be considered in designing better HBV screening and prevention strategies for the armed forces.