Citation: Fofana, D.B.; Somboro,

A.M.; Maiga, M.; Kampo, M.I.;

Diakité, B.; Cissoko, Y.; McFall, S.M.;

Hawkins, C.A.; Maiga, A.I.; Sylla, M.;

et al. Hepatitis B Virus in West

African Children: Systematic Review

and Meta-Analysis of HIV and Other

Factors Associated with Hepatitis B

Infection. Int. J. Environ. Res. Public

Health 2023, 20, 4142. https://

doi.org/10.3390/ijerph20054142

Academic Editor: Paul B. Tchounwou

Received: 17 January 2023

Revised: 17 February 2023

Accepted: 20 February 2023

Published: 25 February 2023

Copyright: © 2023 by the authors.

Licensee MDPI, Basel, Switzerland.

This article is an open access article

distributed under the terms and

conditions of the Creative Commons

Attribution (CC BY) license (https://

creativecommons.org/licenses/by/

4.0/).

International Journal of

Environmental Research

and Public Health

Review

Hepatitis B Virus in West African Children: Systematic Review
and Meta-Analysis of HIV and Other Factors Associated with
Hepatitis B Infection
Djeneba B. Fofana 1,2,* , Anou M. Somboro 1,3 , Mamoudou Maiga 1,4 , Mamadou I. Kampo 5,
Brehima Diakité 1, Yacouba Cissoko 1 , Sally M. McFall 4, Claudia A. Hawkins 4, Almoustapha I. Maiga 1 ,
Mariam Sylla 1, Joël Gozlan 2, Manal H. El-Sayed 6, Laurence Morand-Joubert 2, Robert L. Murphy 4,
Mahamadou Diakité 1 and Jane L. Holl 7

1 Faculty of Medicine, University of Sciences, Techniques and Technologies of Bamako (USTTB),
Bamako BP 1805, Mali

2 Sorbonne Université, INSERM, Institut Pierre Louis d’Epidémiologie et de Santé Publique (iPLESP),
for Department of Virology, Assistance Publique-Hôpitaux de Paris (AP-HP), Saint-Antoine Hospital,
F-75012 Paris, France

3 School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal,
Durban 4041, South Africa

4 Institute for Global Health, Northwestern University, Chicago, IL 60208, USA
5 Hôpital Régional de Tombouctou, Timbuktu, Mali
6 Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt
7 Department of Neurology, University of Chicago, Chicago, IL 60637, USA
* Correspondence: djesfof@gmail.com

Abstract: While Hepatitis B virus (HBV) and the human immunodeficiency virus (HIV) are endemic
in West Africa, the prevalence of HBV/HIV coinfection and their associated risk factors in children
remains unclear. In this review, we sought to assess HBsAg seroprevalence among 0- to 16-year-olds
with and without HIV in West African countries and the risk factors associated with HBV infection
in this population. Research articles between 2000 and 2021 that reported the prevalence of HBV
and associated risk factors in children in West Africa were retrieved from the literature using the
Africa Journals Online (AJOL), PubMed, Google Scholar, and Web of Science databases as search tools.
StatsDirect, a statistical software, was used to perform a meta-analysis of the retained studies. HBV
prevalence and heterogeneity were then assessed with a 95% confidence interval (CI). Publication
bias was evaluated using funnel plot asymmetry and Egger’s test. Twenty-seven articles conducted
across seven West African countries were included in this review. HBV prevalence among persons
aged 0 to 16 years was 5%, based on the random analysis, given the great heterogeneity of the studies.
By country, the highest prevalence was observed in Benin (10%), followed by Nigeria (7%), and Ivory
Coast (5%), with Togo (1%) having the lowest. HBV prevalence in an HIV-infected population of
children was (9%). Vaccinated children had lower HBV prevalence (2%) than unvaccinated children
(6%). HBV prevalence with a defined risk factor such as HIV co-infection, maternal HBsAg positivity,
undergoing surgery, scarification, or being unvaccinated ranged from 3–9%. The study highlights
the need to reinforce vaccination of newborns, screening for HBV, and HBV prophylaxis among
pregnant women in Africa, particularly in West Africa, to achieve the WHO goal of HBV elimination,
particularly in children.

Keywords: prevalence; hepatitis B virus; West Africa; risk factors; HIV; children

1. Introduction

Hepatitis B virus (HBV) infection remains a major cause of acute and chronic liver
disease with significant associated morbidity and mortality, worldwide. The World Health
Organization (WHO) estimated that 296 million people were living with chronic HBV

Int. J. Environ. Res. Public Health 2023, 20, 4142. https://doi.org/10.3390/ijerph20054142 https://www.mdpi.com/journal/ijerph

Int. J. Environ. Res. Public Health 2023, 20, 4142 2 of 20

infection in 2019, with 1.5 million new infections each year and 887,000 deaths due to
chronic HBV infection (CHB) [1]. The risk of chronic infection after exposure to HBV
depends on age at time of infection, with a 90% risk when infection occurs in infancy
and <10% risk when infection occurs in immunocompetent adolescents and adults [2].
Sub-Saharan Africa (SSA) is one of the highest endemic regions with an estimated HBV
surface antigen (HBsAg) sero-prevalence (heretofore referred to as HBV prevalence) of
more than 8% [3]. In SSA countries, including those in West Africa, the main sources of
transmission are mother-to-child during delivery and horizontal during early childhood
through close interaction with infected household contacts [4]. Globally, there are 2 million
estimated new HBV infections in children < 5 years of age [1], resulting in HBV prevalence
of 5–8% in children in SSA, with, for example, a reported 5.8% of five-year-old West African
children being infected [5].

HBV burden is particularly high in HIV-endemic areas. HBV prevalence in the people
living with Human Immunodeficiency Virus/Acquired ImmunoDeficiency Syndrome,
HIV/AIDS is estimated to be more than 7% [6–8]. Given similar transmission mechanisms
of both HBV and HIV, HBV/HIV co-infection is relatively common in HIV-endemic areas
in SSA, in both adults and children. The Joint United Nations Program on HIV/AIDS
(UNAIDS) estimated, in 2019, that 1.7 million children were living with HIV worldwide [9].
Few studies, however, have focused on HIV/HBV co-infection in the pediatric population.
Although, HBV infection is usually asymptomatic during childhood, co-infection poses a
particular challenge as the disease progresses rapidly towards chronicity with increased
risk of mortality from cirrhosis or hepatocellular carcinoma (HCC) [10–12]. In addition,
children are highly vulnerable to HIV infection and are at higher risk of anti-retroviral
therapy (ART) failure compared to adults, especially in resource-limited settings [13,14].

Although HIV treatment significantly reduces vertical transmission, some residual
risk exists when the status of HIV and HBV are not known during pregnancy. In West
Africa, the average childbearing age ranges from 18.8 to 21.8 years and HBV viral load
levels are often high in this age group due to immune tolerance [8,15]. In addition, hepatitis
B e-antigen (HBeAg) status and high HBV viral load during pregnancy are established risk
factors for perinatal transmission [14–16]. However, HBV is a vaccine-preventable disease
with 95% of properly vaccinated children being well protected. The hepatitis B vaccine
(HepB) is recommended for all infants at birth, and for children and adults at high risk [17].

Population-based HBsAg sero-surveys have been recommended as a monitoring tool
for the impact of HepB vaccination programs in areas of high and moderate endemicity.
However, data on chronic HBV prevalence, HIV co-infection, and other associated risk
factors in children in West Africa are limited, particularly following the introduction of
HBV vaccination programs. The absolute number of children chronically infected with
HBV is not known. Yet, for evaluating national vaccination programs and national disease
prevention and control efforts in West Africa and SSA, it is critical to understand the current
prevalence of HBV infection.

We, therefore, conducted a systematic review of published studies, between 2000 and
2021, to assess the prevalence in West Africa of HBsAg sero-positivity among persons
aged 0 to 16 years, with and without HIV infection, to determine the prevalence of HBV
and HIV/HBV co-infection and other risk factors associated with HBV infection in this
population.

2. Materials and Methods
2.1. Inclusion Criteria and Exclusion Reasons

Original research articles in peer-reviewed journals with full-text in English and
available online, published between 2000 and 2021, with a clear and concise description of
the sample types, size, and methods used to assess HBV sero-prevalence were included. We
focused on full-text articles that reported the study design of HBsAg testing to assess HBV
sero-prevalence in persons with or without HIV co-infection, conducted in West African
countries, and included children, aged 0 to 16 years, in the sample.

Int. J. Environ. Res. Public Health 2023, 20, 4142 3 of 20

Studies conducted among West African populations residing outside Africa were ex-
cluded. Systematic reviews, commentaries and editorials, case report studies, surveillance
reports, conference abstracts, animal studies, and articles describing the sero-prevalence of
HBV only among adult populations were excluded. Studies with insufficient or inaccessible
data, pre-prints, studies with a sample size < 100, and studies that did not describe their
sampling technique or that used purposive sampling were excluded.

2.2. Data Sources and Study Screening Strategies

A systematic search, using key search words, was conducted on Africa Journals Online
(AJOL), PubMed, Google Scholar, and Web of Science databases, supplemented by a manual
search of retrieved references. The keywords used were HBV prevalence, children, HBV,
HBV risk factors, HIV co-infection, and the names of the 14 countries of West Africa (Benin,
Burkina Faso, Côte d’Ivoire or Ivory Coast, Cape Verde or Capo Verde, Gambia, Ghana,
Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone,
and Togo). Prior to screening, all identified articles were imported into Covidence, a
systematic review management tool [18]. Two reviewers (D.B.F. and A.M.S.) independently
screened the titles and abstracts for study eligibility and full-text review. Reviewers then
independently read the full text and selected studies for inclusion. After each step of the
review, the two reviewers met and reached consensus on the final selection of studies
for inclusion.

2.3. Description of the Study Area

West Africa is comprised of 14 countries (see above) and has one of the world’s fastest-
growing populations, with more than 420 million people, equivalent to 5% of the total
world population and with a median age of 18 years [19].

2.4. Data Extraction

After full-text review, the two reviewers, individually, extracted data from all eligible
and retained articles, using the Covidence tool. Any differences observed by a reviewer
in data extractio, were reconciled prior to conducting the meta-analysis. In the event of
disagreement, a third reviewer (MIK) was consulted to establish consensus. Information
extracted from the articles included: sociodemographic characteristics, sample size, the
prevalence of HBsAg, risk factors including HIV co-infection, mother’s HBsAg status, HBV
contact(s) in the family, blood transfusion, circumcision, or other scarification, surgery, and
receipt of HepB vaccine, including a birth dose.

2.5. Quality Assessment

The Newcastle–Ottawa scale (NOS) for cross-sectional studies quality assessment tool
was used to assess the quality of each study [20]. The tool includes multiple sections. The
first section focuses on the sample selection of each study. The second section deals with
the comparability of the study including type of study, diagnostic method, and year of
publication. The last section focuses on the statistical analysis of each study. A total NOS
score ranges from 0 to 10. Study scores of 9–10 points are considered very good, 7–8 as
good and 5–6 as satisfactory.

2.6. Data Analysis

StatsDirect, a statistical software (Version 3.0.0, StatsDirect Ltd., Cheshire, UK) was
used to conduct the meta-analysis of the proportions of HBsAg in the retained studies [21].
Individual study proportions were assessed with a 95% confidence interval (CI) and the
pooled effect. Sources of variation among studies were assessed by sub-group analysis,
using the following grouping variables: study setting (hospital/other health care setting
versus community setting), year of study, year of publication, and the prevalence of HBsAg
among children, aged 0–16 years, stratified by “with” group risk factors, “without” group

Int. J. Environ. Res. Public Health 2023, 20, 4142 4 of 20

risk factors, and individual risk factors including HIV status, with HBsAg positive mother,
and HBV vaccination including birth dose status.

We also assessed the study type, country, sample type, and testing method. Hetero-
geneity across the studies was assessed by the Quoran (Q) statistic test and the I2 statistic.
High heterogeneity (I2 > 73% and p het < 0.05) represents the percentage of total vari-
ation across studies, attributable to heterogeneity rather than to chance [22]. Sources of
heterogeneity were analyzed through sub-group analysis and one sensitivity analysis of
HIV/HBV co-infection.

Publication bias was evaluated using funnel plot asymmetry and Egger’s test [23].
In this test, p > 0.05 indicates an absence of evidence of publication bias (not significant).
A random-effects model (REM) was used to pool HBV prevalence. Some representative
results of the REM are presented graphically using forest plots.

We also assessed publication bias analysis in different subgroups. A sensitivity analysis
was carried out by excluding 2 studies likely to strongly bias the results of HBV prevalence.
Analyses of HBV prevalence were assessed with a 95% CI and p < 0.05 was considered as
significant. All calculations were done using the StatsDirect software version 3.

3. Results
3.1. Study Selection

The databases and other literature search tools yielded a total of 1162 articles. Figure 1
summarizes the flow chart for the selection of studies. Duplicate articles (n = 713), due
to the diverse search tools used, were removed. Titles and/or abstracts were first used to
screen the articles, according to the systematic review and meta-analysis criteria. After
screening, 157 articles were further excluded because of a sample size < 100 and/or not
within the publication period. However, data were extracted from four general population
studies with more than 100 children and adolescents in each of the studies [24–27]. Of the
278 articles fully screened, 253 were excluded, based on the inclusion and exclusion criteria,
as described in the Methods section. A total of 27 articles met the eligibility criteria for the
meta-analysis. The included studies were conducted in seven of the fourteen West African
countries, Nigeria (thirteen articles), Senegal (five articles), Burkina Faso and Ghana (three
articles each), Benin, Togo, and Ivory Coast (one article each), as shown in Table 1.

3.2. Characteristics of the Systematic Review Studies

Four were cohort studies, nineteen were cross-sectional, three were retrospective
cohort studies, and one was case-control. A total of 11,304 children, aged 0 to 16 years,
were included in the retained studies, with studies from Nigeria accounting for most
children (3747), of which, 270 were HbsAg positive (270/3747 = 7.2%), followed by Senegal
with 3417 children and 80 HBsAg positive, (80/3417 = 2.3%), Burkina Faso, 2383 children
(103/2383 = 4.3%), Ghana, 1661 (19/1161 = 1.6%), Ivory coast, 285, (15/2825.3%), Togo, 210
(3/210 = 1.4%) and Benin 103 (10/103 = 9.7%), (Supplementary Data S1). We observed a
decrease in the prevalence of HBV between 2000 and 2021. HBV prevalence by country
and study periods calculated by the StatsDirect software are presented in Figures 2 and 3,
respectively.

Multiple techniques were reported to detect HBsAg, with direct enzyme-linked im-
munoassay test (ELISA) being the most common, followed by rapid diagnostic assays
(RDT) using serum or plasma serological markers of HBV.

Nineteen (n = 19), 70% of the studies were conducted in hospital settings and eight
(30%) in community settings. Most of the studies involved children only, although we
extracted data from four studies of the general population that included >100 children,
0–16 years old [24–27].

Nine (=9), 33% of studies included persons living with HIV (PLWH), including a total
of 2317 children, and three studies included high-risk children born to HBsAg-positive
mothers. Most studies were conducted in urban areas, with only four studies being in

Int. J. Environ. Res. Public Health 2023, 20, 4142 5 of 20

mixed urban and rural areas. Seven (n = 7), 26% of studies included HepB vaccine status;
however, most studies were missing vaccination information (Supplementary Data S2).

Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 5 of 20

Records identified through

database searching

(n = 857)

S
cr

ee
n

in
g

In

cl
u

d
ed

E

li
g

ib
il

it
y

Id

en
ti

fi
ca

ti
o

n

Additional records identified

through other sources

(n = 305)

Records after duplicates removed

(n = 449)

Records screened

(n = 435)

Records excluded

(n = 157)

Small sample size (72)

Wrong setting (47)

Not in West Africa (38)

Full-text articles assessed

for eligibility

(n = 278)

Full-text articles excluded,

with

reasons

(n = 253)

Adult population (119)

Wrong intervention (107)

Missing testing data (8)

No abstract (3)

Wrong outcomes, study

design (6)

Other Viruses infection (6)

Studies included in

qualitative synthesis

(n = 28)

Studies included in

quantitative synthesis

(meta-analysis)

(n = 27)

Figure 1. Study Eligibility Flow Diagram.

Figure 1. Study Eligibility Flow Diagram.

Int. J. Environ. Res. Public Health 2023, 20, 4142 6 of 20

Table 1. Characteristics of Systematic Review Studies and Meta-Analysis of HBV Prevalence in Children in West Africa.

1st Author
[Reference]

Study
Setting Study Year

Publication
Year Country Study Type

Sample
Size

Number
AgHBs+

Prevalence of
AgHB+ (%)

Diagnostic
Method Sample Type

Score
Quality

Studies in Hospital Settings

Adeoye OA [28] Urban 2012 2021 Nigeria Cross-sectional 261 3 1.1 ELISA SERA 7

Anigilaje EA [29] Urban 2008–2012 2013 Nigeria Cross-sectional 395 31 7.8 ELISA SERA 10

Barro M [30] Urban 2013 2019 Burkina Faso Cohort 2015 53 2.6 ELISA PLASMA 9

d’Almeida M [31] Urban 2014 2015 Benin Cross-sectional 104 10 9.6 RDT PLASMA 9

Ezeilo MC [32] Urban 2017 2018 Nigeria Cross-sectional 270 31 22.5 ELISA PLASMA 7

Ikpeme EE [33] Urban 2010–2011 2013 Nigeria Cohort 166 10 6.0 ELISA SERA 9

Bukbuk DN [27] Urban 2009–2010 2016 Nigeria Cohort 177 44 24.9 ELISA SERA 6

LO G [34] Urban 2016 2019 Senegal Cross-sectional 295 3 1.1 ELISA SERA 9

Edward AD [35] Urban 2004 2007 Nigeria Retrospective 251 31 12 ELISA SERA 7

Ekouevi DK [36] Urban 2017 2020 Togo Cross-sectional 210 3 1.3 RDT SERA 7

Nacro B [37] Urban 2001 2001 Burkina Faso Cross-sectional 103 41 39.8 RDT SERA 8

Nwolisa E [38] Urban 2010 2013 Nigeria Cross-sectional 139 8 5.8 RDT SERA 6

Toyé RM [39] Urban 2015 2021 Senegal Retrospective 613 25 4.1 RDT SERA 8

Ashir GM [40] Urban 2007 2009 Nigeria Cross-sectional 284 54 2.8 ELISA SERA 7

Apiung T [41] Urban 2012–2013 2017 Ghana Cross-sectional 424 3 0.05 ELISA PLASMA 7

Sadoh AE [42] Urban 2011 2014 Nigeria Cross-sectional 150 21 13.9 ELISA SERA 8

Hagan OCK [43] Urban 2012–2013 2018 Ghana Cross-sectional 387 11 2.8 ELISA SERA 7

Ba A [44] Urban 2013–2015 2018 Senegal Cross-sectional 252 7 2.8 ELISA SERA 7

Quaye T [45] Urban 2019 2021 Ghana Cross-sectional 350 5 1.4 ELISA SERA 8

Int. J. Environ. Res. Public Health 2023, 20, 4142 7 of 20

Table 1. Cont.

1st Author
[Reference]

Study
Setting Study Year

Publication
Year Country Study Type

Sample
Size

Number
AgHBs+

Prevalence of
AgHB+ (%)

Diagnostic
Method Sample Type

Score
Quality

Studies in Community Settings

Gueye SB [46] Urban 2007–2012 2016 Senegal Retrospective 930 28 3.0 ELISA TOTAL BLOOD 7

Omeje KN [26] Urban 2010–2011 2017 Nigeria Cross-sectional 208 6 2.8 RDT SERA 5

Sanou AM [47] Rural 2015 2018 Burkina Faso Cross-sectional 265 9 3.4 RDT SERA 6

Périères L [48] Rural 2018–2019 2021 Senegal Cross-sectional 1327 17 1.2 ELISA SERA 10

Ouattara A [25] Urban 2006 2019 Cote d’Ivoire Cross-sectional 282 15 5.3 ELISA SERA 9

Odusanya OO [49] Rural/Urban 2001 2005 Nigeria Case control 223 3 1.2 ELISA SERA 8

Odusanya OO [49] Rural/Urban 2001 2005 Nigeria Case control 219 10 4.6 ELISA SERA 8

Ikobah J [50] Urban 2014 2016 Nigeria Cross-sectional 595 6 0.6 RDT SERA 7

Adoga, MP [24] Urban 2008–2009 2010 Nigeria Cohort 409 12 2.9 ELISA SERA/PLASMA 8

Int. J. Environ. Res. Public Health 2023, 20, 4142 8 of 20

Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 7 of 20

3.2. Characteristics of the Systematic Review Studies

Four were cohort studies, nineteen were cross-sectional, three were retrospective co-

hort studies, and one was case-control. A total of 11,304 children, aged 0 to 16 years, were

included in the retained studies, with studies from Nigeria accounting for most children

(3747), of which, 270 were HbsAg positive (270/3747 = 7.2%), followed by Senegal with

3417 children and 80 HBsAg positive, (80/3417 = 2.3%), Burkina Faso, 2383 children

(103/2383 = 4.3%), Ghana, 1661 (19/1161 = 1.6%), Ivory coast, 285, (15/2825.3%), Togo, 210

(3/210 = 1.4%) and Benin 103 (10/103 = 9.7%), (Supplementary Data S1). We observed a

decrease in the prevalence of HBV between 2000 and 2021. HBV prevalence by country

and study periods calculated by the StatsDirect software are presented in Figure 2 and

Figure 3, respectively.

Figure 2. Overall HBV Prevalence in Children, 0–16 Years Old, in West Africa, Pooled by Country.

A black square represents the HBV prevalence in the forest plot. The square position represents the

prevalence.

Figure 2. Overall HBV Prevalence in Children, 0–16 Years Old, in West Africa, Pooled by Country.
A black square r presents the HBV pr vale ce in th forest plot. The square position repres nts
the prevalence.

Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 8 of 20

Figure 3. Forest Plot of Pooled HBV Prevalence by Year of Study Interval. A black square represents

the HBV prevalence in the forest plot. The square position represents the prevalence.

Multiple techniques were reported to detect HBsAg, with direct enzyme-linked im-

munoassay test (ELISA) being the most common, followed by rapid diagnostic assays

(RDT) using serum or plasma serological markers of HBV.

Nineteen (n = 19), 70% of the studies were conducted in hospital settings and eight

(30%) in community settings. Most of the studies involved children only, although we

extracted data from four studies of the general population that included >100 children, 0–

16 years old [24–27].

Nine (=9), 33% of studies included persons living with HIV (PLWH), including a total

of 2317 children, and three studies included high-risk children born to HBsAg-positive

mothers. Most studies were conducted in urban areas, with only four studies being in

mixed urban and rural areas. Seven (n = 7), 26% of studies included HepB vaccine status;

however, most studies were missing vaccination information (Supplementary Data S2).

3.3. Overall Pooled HBV Prevalence in Children in West Africa and Publication Bias

HBV prevalence among children, 0–16 years old, varied widely in West Africa (Fig-

ure 4A). Crude overall HBV prevalence in the pooled sample of 11,304 children was 5%

(95%, CI 4–7%). The seroprevalence data are presented in the random effect model be-

cause of the substantial heterogeneity of HBV prevalence across the studies (I2 > 94.2%,

95% CI = 93% to 95.1%). Egger’s test was significant (p < 0.001) for HBV prevalence, sug-

gesting publication bias in the studies (Figure 4B).

Figure 3. Forest Plot of Pooled HBV Prevalence by Year of Study Interval. A black square represents
the HBV prevalence in the forest plot. The square position represents the prevalence.

3.3. Overall Pooled HBV Prevalence in Children in West Africa and Publication Bias

HBV prevalence among children, 0–16 years old, varied widely in West Africa (Figure 4A).
Crude overall HBV prevalence in the pooled sample of 11,304 children was 5% (95%, CI
4–7%). The seroprevalence data are presented in the random effect model because of the
substantial heterogeneity of HBV prevalence across the studies (I2 > 94.2%, 95% CI = 93% to
95.1%). Egger’s test was significant (p < 0.001) for HBV prevalence, suggesting publication
bias in the studies (Figure 4B).

Int. J. Environ. Res. Public Health 2023, 20, 4142 9 of 20Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 9 of 20

Figure 4. (A) Forest Plot of Global HBV Prevalence in Children in West Africa, 2000 and 2021. A

black square represents the HBV prevalence in the forest plot. The square position represents the

prevalence in each study in the meta-analysis [24–34,36–50]. (B) Bias Assessment Plot.

3.4. Sensitivity Analysis

To further assess the strength of the HBV prevalence results, we conducted a leave-

two-out sensitivity analysis by removing two studies that included two high-risk popula-

tions: a study of HBV-HIV co-infected children with high HBV prevalence [37] and a study

of infants born to HBsAg positive mothers [27]. The overall HBsAg positive pooled prev-

alence rate was 5% with heterogeneity prior to the exclusion of these two studies (I2 of

94.2%, 95% CI = 93% to 95.1%, p < 0.0001). However, after the exclusion, the pooled prev-

alence rate only dropped to 4% (95% CI 3% to 6%) with heterogeneity (I2 of 91.2%, 95% CI

= 88.8% to 92.9%), indicating that the pooled HBV prevalence was not affected by the two

studies and that the results are robust (Supplementary Data S3).

3.5. HBV Prevalence in Children with or without Risk Factors

Overall, HBV prevalence in children ranged from 4% (95%CI: 0.03 to 0.06) in children

without risk factors, (Figure 5A) to 9% (95%CI: 5 to 15%) in children with at least one risk

factor, such as HIV/HBV co-infection or being born to an HbsAg positive mother (Figure

5B).

B

Figure 4. (A) Forest Plot of Global HBV Prevalence in Children in West Africa, 2000 and 2021. A
black square represents the HBV prevalence in the forest plot. The square position represents the
prevalence in each study in the meta-analysis [24–34,36–50]. (B) Bias Assessment Plot.

3.4. Sensitivity Analysis

To further assess the strength of the HBV prevalence results, we conducted a leave-two-
out sensitivity analysis by removing two studies that included two high-risk populations:
a study of HBV- IV co-infected children with high HBV prevalence [37] and a study of
infants born to HBsAg positive mothers [27]. The overall HBsAg positive pooled prevalence
rate was 5% with heterogeneity prior to the exclusion of these two studies (I2 of 94.2%, 95%
CI = 93% to 95.1%, p < 0.0001). However, after the exclusion, the pooled prevalence rate
only dropped to 4% (95% CI 3% to 6%) with heterogeneity (I2 of 91.2%, 95% CI = 88.8 to
92.9%), indicating that the pooled HBV prevalence was not affected by the two studies and
that the results are robust (Supplementary Data S3).

. . re le ce i il re it r it t is ct rs

er ll, re le ce i c il re r e fr ( I: . t . ) i c il re
it o t risk factors, (Figure 5A) to 9% (95%CI: 5 to 15%) in children with at least one

risk factor, such as I /HBV co-infection or being born to an HbsAg positive mother
(Figure 5B).

Int. J. Environ. Res. Public Health 2023, 20, 4142 10 of 20Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 10 of 20

Figure 5. Forest Plots of HBV Prevalence in Children 0–16 Years Old in West Africa, (A) Without

Risk Factors and (B) With Risk Factors [24–34,36–41,43–45,47–50]. A black square represents the

HBV prevalence in the forest plot. The square position represents the prevalence in each study in

the meta-analysis.

A funnel plot of HBV prevalence in children with and without HIV shows a not

strictly symmetrical display of the prevalence reported by the individual studies (Figure

3). However, the random effects model (DerSimonian Laird) suggests that there is evi-

dence of publication bias, as revealed by the Egger’s test, with a bias = 4.447819 (95% CI =

3.043189 to 5.852449) and p < 0.0001.

3.6. Risk Factors of HBV Infection in Children

An analysis of children by individual risk factor shows HBV prevalences of 12%, 8%,

5%, and 1% in children born to HBsAg positive mothers, HBV/HIV co-infected, unvac-

cinated with a birth dose, and vaccinated, respectively, as shown in Figure 6.

Figure 6. Pooled HBV Infection Prevalence by Risk Factor A black square represents the HBV pre-

valence in the forest plot. The square position represents the prevalence.

A B

Figure 5. Forest Plots of HBV Prevalence in Children 0–16 Years Old in West Africa, (A) Without
Risk Factors and (B) With Risk Factors [24–34,36–41,43–45,47–50]. A black square represents the HBV
prevalence in the forest plot. The square position represents the prevalence in each study in the
meta-analysis.

A funnel plot of HBV prevalence in children with and without HIV shows a not
strictly symmetrical display of the prevalence reported by the individual studies (Figure 3).
However, the random effects model (DerSimonian Laird) suggests that there is evidence of
publication bias, as revealed by the Egger’s test, with a bias = 4.447819 (95% CI = 3.043189
to 5.852449) and p < 0.0001.

3.6. Risk Factors of HBV Infection in Children

An analysis of children by individual risk factor shows HBV prevalences of 12%,
8%, 5%, and 1% in children born to HBsAg positive mothers, HBV/HIV co-infected,
unvaccinated with a birth dose, and vaccinated, respectively, as shown in Figure 6.

Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 10 of 20

i r . rest lots of revalence in hildren 0–16 Years l i t fri , ( ) it t

Risk Factors and (B) With Risk Factors [24–34,36–41,43–45,47–50]. A black square represents the

HBV prevalence in the forest plot. The square position represents the prevalence in each study in

the meta-analysis.

A funnel plot of HBV prevalence in children with and without HIV shows a not

strictly sy etrical display of the prevalence reported by the individual studies (Figure

3). However, the random effects model (DerSimonian Laird) suggests that there is evi-

dence of publication bias, as revealed by the Egger’s test, with a bias = 4.447819 (95% CI =

3.043189 to 5.852449) and p < 0.0001.

. . is t rs f I fectio i il re

analysis of children by indiv dual risk factor shows HBV preval nces of 12%, 8 ,

5 , and 1% in children bor to HBsAg positive mothers, HBV/HIV co-infected, unvac-

ci ated with a birth dose, and vaccinated, respectively, as shown in Figure 6.

Figure 6. Pooled HBV Infection Prevalence by Risk Factor A black square represents the HBV pre-

valence in the forest plot. The square position represents the prevalence.

A B

Figure 6. Pooled HBV Infection Prevalence by Risk Factor A black square represents the HBV
preval nce in the forest plot. The square position r presents the preval nce.

Int. J. Environ. Res. Public Health 2023, 20, 4142 11 of 20

3.7. HBV Prevalence in Hospital and Community Settings

Subgroup analysis showed higher HBV prevalence in studies conducted in hospital
settings [7% (95% CI. 4 to 11%)] compared to studies conducted in community settings
among children without any risk factors [3% (95%CI: 2 to 4%)] (Figure 7A,C).

Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 11 of 20

3.7. HBV Prevalence in Hospital and Community Set ings

Subgroup analysis sho ed higher BV prevalence in studies conducted in hospital

settings [7 (95 CI. 4 to 11 )] c ared to st ies c ucted in co unity settings

a ong children itho t a y ris fact rs [ ( I: t )]. ( i r , )

Figure 7. (A) Forest Plots of HBV Prevalence in Children, 0–16 Years Old, in West Africa, Conducted

in Community Settings, (B) Heterogeneity in Community Setting Studies, (C) Forest Plots of HBV

Prevalence in Hospital Settings, and (D) Heterogeneity in Hospital Setting Studies [24–26,28–34,36–

41,43–48]. A black square represents the HBV prevalence in the forest plot. The square position rep-

resents the prevalence in each study in the meta-analysis.

Community setting studies had an Egger Bias of 2.685631 (95% CI = 1.00063 to

4.370632) (p = 0.0094), corresponding to low heterogeneity between studies, compared to

an Egger Bias of 5.116854 (95% CI = 2.916234 to 7.317473) (p = 0.0002) for hospital setting

studies, corresponding to a high heterogeneity (Figure 7B,D).

3.8. HBV Prevalence by HIV Status in Children

HBV/HIV co-infected children had an overall HBV prevalence of 9% (95% CI: 4 to

15%), with an Egger bias of 6.253247 (95% CI = 2.533005–9.97349; p = 0.0054), correspond-

ing to low heterogeneity between studies, as opposed to studies of HBV mono-infected

children who had an overall HBV prevalence of 4% (95% CI, 2 to 6%) and an Egger bias

of 3.7865 (Figure 8).

Figure 7. (A) Forest Plots of HBV Prevalence in Children, 0–16 Years Old, in West Africa, Conducted in
Community Settings, (B) Heterogeneity in Community Setting Studies, (C) Forest Plots of HBV Preva-
lence in Hospital Settings, and (D) Heterogeneity in Hospital Setting Studies [24–26,28–34,36–41,43–48].
A black square represents the HBV prevalence in the forest plot. The square position represents the
prevalence in each study in the meta-analysis.

Community setting studies had an Egger Bias of 2.685631 (95% CI = 1.00063 to 4.370632)
(p = 0.0094), corresponding to low heterogeneity between studies, compared to an Egger
Bias of 5.116854 (95% CI = 2.916234 to 7.317473) (p = 0.0002) for hospital setting studies,
corresponding to a high heterogeneity (Figure 7B,D).

3.8. HBV Prevalence by HIV Status in Children

HBV/HIV co-infected children had an overall HBV prevalence of 9% (95% CI: 4 to
15%), with an Egger bias of 6.253247 (95% CI = 2.533005–9.97349; p = 0.0054), corresponding
to low heterogeneity between studies, as opposed to studies of HBV mono-infected children

Int. J. Environ. Res. Public Health 2023, 20, 4142 12 of 20

who had an overall HBV prevalence of 4% (95% CI, 2 to 6%) and an Egger bias of 3.7865
(Figure 8).

Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 12 of 20

Figure 8. (A) Forest Plots of HBV/HIV Co-Infected Children, (B) Bias Assessment of Co-Infected

Children, (C) Forest Plots of HBV Mono-Infected Children, (D) Bias Assessment of HBV Mono-In-

fected Children [24–34,36–40,42–45,47–50]. A black square represents the HBV prevalence in the

forest plot. The square position represents the prevalence in each study in the meta-analysis.

HBV Prevalence among Vaccinated and Unvaccinated Children

HBV prevalence was still high in studies of unvaccinated children [6% (95%, CI: 4%–

8%)] (Figure 9A) compared to studies of vaccinated children [2% (95%, CI: 1%–3%)] (Fig-

ure 9B). Due to a lack vaccination status data in most studies, HBV prevalence caused by

natural infection (anti-HBs + anti-HBc) could not be evaluated.

Figure 8. (A) Forest Plots of HBV/HIV Co-Infected Children, (B) Bias Assessment of Co-Infected
Children, (C) Forest Plots of HBV Mono-Infected Children, (D) Bias Assessment of HBV Mono-
Infected Children [24–34,36–40,42–45,47–50]. A black square represents the HBV prevalence in the
forest plot. The square position represents the prevalence in each study in the meta-analysis.

HBV Prevalence among Vaccinated and Unvaccinated Children

HBV prevalence was still high in studies of unvaccinated children [6% (95%, CI: 4–8%)]
(Figure 9A) compared to studies of vaccinated children [2% (95%, CI: 1–3%)] (Figure 9B).
Due to a lack vaccination status data in most studies, HBV prevalence caused by natural
infection (anti-HBs + anti-HBc) could not be evaluated.

Int. J. Environ. Res. Public Health 2023, 20, 4142 13 of 20Int. J. Environ. Res. Public Health 2023, 20, x FOR PEER REVIEW 13 of 20

Figure 9. (A) HBV Prevalence Among Unvaccinated and (B) Vaccinated Children [24–34,36–

41,43,45–47,49]. A black square represents the HBV prevalence in the forest plot. The square posi-

tion represents the prevalence in each study in the meta-analysis.

4. Discussion

A systematic review of HBV prevalence in children in West Africa aged 0–16 years

yielded 27 studies meeting inclusion criteria for a meta-analysis. The studies, however,

only included data from seven of West Africa’s fourteen countries. Most studies were

cross-sectional; three-quarters used the Enzyme-Linked Immunosorbent Assay (ELISA)

as the HBV diagnostic tool, and most were conducted in a hospital setting (18/27) in an

urban area. Indeed, most healthcare facilities in West Africa are in urban areas.

Overall, HBV prevalence was 5%, based on the random analysis, given the heteroge-

neity of the studies. This meta-analysis revealed that HBV prevalence in children in West

Africa is moderate, according to the WHO’s criteria for HBV endemicity [51]. HBV prev-

alence by country ranged from 1% in Togo to 10% in Benin. The prevalence was also var-

iable inside the same country, such as in Nigeria or Ghana, for which there are a high

number of published data available. Differences in health system resources across West

African countries, although already generally limited in all of West Africa, may still ex-

plain some of the discrepancies. In fact, some countries such as Mali and Benin lack re-

sources to screen pregnant women or provide vaccine doses at birth for newborns. Find-

ings from a study with timely dose of hepatitis B Birth dose (HepB-BD) in Africa demon-

strated the variability of birth dose implementation and the challenges countries face in

immunizing babies [52]. In the absence of efforts for preventing mother-to-child transmis-

sion, it is anticipated that HBV prevalence in children in these countries would stay higher

and fall short of the WHO targets.

Due to the significant burden of HBV-related diseases in SSA, where >8% of the gen-

eral population is chronically infected, HBV infection is still ubiquitous across West Af-

rica. This can impact HBV prevalence in these countries [53] and the prevalence is around

5% among pregnant HBV/HIV co-infected women [54]. There has been a significant

Figure 9. (A) HBV Prevalence Among Unvaccinated and (B) Vaccinated Children [24–34,36–41,43,45–
47,49]. A black square represents the HBV prevalence in the forest plot. The square position represents
the prevalence in each study in the meta-analysis.

4. Discussion

A syste atic review of BV prevalence in children in est Africa aged 0–16 years
yielded 27 studies eeting inclusion criteria for a eta-analysis. The studies, however,
only included data fro seven of est frica’s fourteen countries. ost studies ere
cross-sectio al; t ree-q arters se the Enzyme-Linked Immunosorbent Assay (ELISA) as
the HBV diagnostic tool, and most were conducted in a hospital setting (18/27) in an urban
are . Indeed, most healthcare facilities in West Africa are in urba are s.

verall, HBV prevalence was 5%, based on the random nalysis, given t hetero-
geneity of the studies. This met -analysis revealed that HBV prevalence in children in
West Africa is moderate, according to the WHO’s criteria for HBV endemicity [51]. HBV
prevalence by country ranged from 1% in T go to 10% in Benin. The prevalence was also
variable insid the same country, such as in Nigeria or Ghana, for which there are a high
nu ber of published data available. Di ferences in health system resources acro s est

fric lt h already generally limited in all of West Africa, may still explain
some f the discrepancies. In fact, some c untries such as Mali and Be in lack resourc s
t screen pregnant women or provide vaccin doses at birth for newb ns. Findings from
a study with timely dose of hepatitis B Birth dose (HepB-BD) in Africa demonstrated the
variability of birth dose implementation and the challenges countries face in immunizing
babies [52]. In the absence of efforts for preventing mother-to-child transmission, it is
anticipated that HBV prevalence in children in these countries would stay higher and fall
short of the WHO targets.

Due to the significant burden of HBV-related diseases in SS , here >8% of the gen-
eral population is chronically infected, HBV infection is still ubiquitous across West Africa.
This can impact HBV prevalence in these countries [53] and the prevalence is around 5%
among pregnant HBV/HIV co-infected women [54]. There has been a significant decrease

Int. J. Environ. Res. Public Health 2023, 20, 4142 14 of 20

in the prevalence of HBsAg among children in West Africa since the year 2000. This is
clearly demonstrated by comparing the 12% HBsAg prevalence in children and adoles-
cents < 19 years old in West African SSA in 1990 [51], and the prevalence of HBV infection in
children at 2.53% in 2019, amounting to 360,000 infected children each year [55]. We believe
that the decrease may be related to the introduction of infant HBV vaccination programs in
most African countries and including the HepB-BD in a few countries.

Studies conducted in hospital settings showed higher prevalence of HBV infection
(7%) and this is likely related to the studies being conducted on sick children, who are also
tested at higher rates than non-hospitalized children. By contrast, healthy children in the
community setting had an HBV prevalence of only 3% and may represent early success
of the newborn HepB vaccination programs. Prevalence varied from 3% to 9% among
infants with HBV/HIV co-infection, those born to mothers who tested positive for HBsAg,
and those who had other risk factors, such as having undergone surgery, scarification,
or not receiving vaccinations. Other risk factors were not available in many studies. In
one Nigerian study, risk factors such as previous history of jaundice (p = 0.26), blood
transfusion (p = 0.24), past history of surgery (p = 0.47), or scarification marks (p = 0.17)
were not associated with HBV prevalence [26].

HIV and HBV infections have many similarities, such as common routes of trans-
mission, high prevalence in certain geographical regions, same at-risk groups, and the
risk of mother-to-child transmission. All these factors contribute to a significant associ-
ation between HBV and HIV co-infection in the pediatric population [56,57]. We found
an overall HIV/HBV co-infected prevalence of 9%. However, in a sensitivity analysis, we
removed one study from Burkina Faso (2001) that reported a co-infection rate of 40%, and
yielded a prevalence of 6%, ranging from 1.15% in Nigeria (2021) to 10% in Benin (2015)
(Figure 3). The finding from this study is consistent with prior studies. In studies from
South Africa, HIV/HBV co-infection prevalence in children ranged from 5–17%, with the
higher prevalence occurring in the industrialized towns where mining activity is associated
with increased sexual activity. In Nigerian studies, HBV/HIV co-infection prevalence
varied by geopolitical region, ranging from 5.8 to 19% [13,29,38,40,58]. Finally, a Tanzanian
study of HBV/HIV co-infected children reported 1.2% prevalence [59]. Reported HBV/HIV
co-infection prevalence in children has been somewhat higher in Nigeria (7.8%) [29], 10.4%
in Zambia [60], and 12.1% in Ivory Coast [61]. The generational effect benefits of HepB
vaccination may be a factor in the relatively lower HBV-HIV co-infection in later stud-
ies compared to earlier studies. It is also important to note that HIV/HBV co-infection
considerably increases the risk of mother-to-child transmission, if the mother is infected
and untreated.

Perinatal and childhood acquisition of HBV not only leads to increased risk of chronic-
ity but also strongly predict worse long-term outcomes for liver cirrhosis and hepatocellular
carcinoma [16]. HIV/HBV co-infection in childhood further places children at high risk for
associated morbidity and mortality, similar to adults, hence the urgent need to implement
HepB vaccination at birth, routine screening, and follow-up. In fact, despite more than two
decades since the introduction of HepB vaccination programs, the overall prevalence of
HBV infection still remains high in many settings in SSA [53,62,63].

The difference in HBV prevalence infection between vaccinated and unvaccinated
children is still substantial (2% versus 6%). While there is a residual possibility of HBV
infection despite newborn HepB vaccination, often, it is unclear if infection occurred before
or after completion of the HepB vaccine series [41]. In SSA, horizontal transmission in
children, aged 6 months to 5 years, is common due to close interactions with infected
household contacts and playmates. We examined the impact of HepB newborn vaccination
compared to the evolution of the epidemic in each country. In Nigeria, overall HBV
prevalence was 7% and a case-control study found that HBsAg prevalence was significantly
lower among vaccinated (1.4%) compared with unvaccinated (4.8%) children [49]. In
Senegal and Ghana, where all the studies were conducted after newborn HepB vaccination
had been introduced, overall HBV prevalence was only 2%. In Togo, one in ten women of

Int. J. Environ. Res. Public Health 2023, 20, 4142 15 of 20

childbearing age was infected with HBV, but less than 2% of infants under five years of age
who received the HepB vaccine at birth were infected with HBV. These results are similar to
other studies that found significant reductions in HBsAg positivity post-vaccination with a
protective efficacy of between 67–94% [64,65]. Such a high level of vaccine efficacy is likely
to positively impact and prevent community transmission of HBV.

In 1992, the World Health Assembly adopted a resolution recommending the introduc-
tion of HepB into national immunization programs [66]. In 2016, the WHO and the World
Health Assembly established the target of controlling and eliminating HBV worldwide by
2030. The WHO recommends that all infants receive their first dose of HepB as soon as pos-
sible after birth, ideally within 24 h, followed by two or three doses of HepB at least 4 weeks
apart to complete the vaccination series [67]. Despite this recommendation, HepB vaccina-
tion at birth has not been widely implemented in most national vaccination programs in
SSA, particularly in West Africa, despite the Expanded Program of Immunization (EPI) [68].
Indeed, in most West African countries, parents must still pay for the first HepB dose, which,
at ~$US 8 per dose, is prohibitive, given that 85% of the population in SSA live on less than
$5.50/day [69]. In 2021, coverage with timely HepB-BD was 42% globally and only 17% for
infants in the WHO African region [70]. A total of 114 countries worldwide had introduced
HepB-BD in their routine immunization schedule [71]. Yet, this number includes only 14
(30%) of 47 countries in the WHO African region [72]. Limited countries have data on Stud-
ies of the Effectiveness of HepB-BD Vaccination in Africa with only two studies published
to date. In 2001–2002, Ekra and colleagues conducted a nonrandomized controlled trial
in four health centers in Abidjan, Cote d’Ivoire [73] and a second effectiveness study was
conducted from 2009–2016 in a single center in Tokombéré district, Cameroon [74]. Based
on the results of those published studies, the authors assumed a high-level transmission
rate in the absence of vaccination and highlighted the benefit of the addition of HepB-BD to
the three-dose HepB vaccination schedule for infants. In addition, a residual risk of mother-
to-child transmission of hepatitis B virus infection despite timely birth-dose vaccination in
Cameroon has been reported. In addition, studies from Hawaii, Taiwan, and China provide
assurance that routine infant HepB immunization beginning with HepB-BD vaccination is a
highly effective public health strategy that will progressively protect generations to come
from HBV-related liver disease, HCC, and premature mortality [75,76].

The universal vaccination strategy implemented in Thailand provides evidence of the
effect of newborn HepB vaccination (HepB-BD) in eliminating HBV infection [77]. As more
African countries seek to implement HepB-BD, attention to disparities in implementation
need to be addressed particularly in rural and underprivileged settings [63]. Maternal edu-
cation and community engagement are essential to scale up HepB-BD in SSA through the
Global Alliance for Vaccines and Immunisation (GAVI). A study in Nigeria demonstrated
that missed doses were largely avoided when staff completed a vaccine checklist before
releasing mother–child pairs [78]. There must also be a focus on offsetting the costs of
distributing the HepB-BD throughout SSA.

In endemic regions of Africa and Asia, in-utero infection of the fetus, vertical transmis-
sion, constitutes the main mode of HBV transmission [79]. A meta-analysis indicated that
maternal viral load was an important risk factor for mother-to-child transmission (MTCT)
in HBeAg-positive mothers, and maternal viral load was dose-dependent with HBV MTCT
incidence [80]. Other studies have shown that a high viral load in HBsAg-positive mothers
can lead to vaccination failure in the newborn, even if combined immunoglobin treatment
and vaccination at birth are delivered [81].

HBsAg screening for all pregnant women is critical. Focusing on HBsAg positive
women and providing prophylactic treatment to women with high viral loads can be
an effective approach to reduce transmission to the infant [82]. A Senegalese study of
HBV in children born to HIV-positive mothers showed a low rate of HBsAg (2.6%) if the
mother was treated with lamivudine (3TC) or tenofovir (TDF), compared to 7.9% if the
mother was untreated [46]. Another Senegalese study showed low HBV prevalence, but
only 56% of children had a sero-protective level >10 UI/L [34]. It is, therefore, strongly

Int. J. Environ. Res. Public Health 2023, 20, 4142 16 of 20

recommended to vaccinate children and to adhere to the necessary doses to protect them
against HBV infection.

Limitations

This meta-analysis has several limitations, particularly the substantial heterogeneity of
eligible studies. Prior HBV prevalence meta-analyses in Africa have also had high levels of
heterogeneity [83,84]. Data about children, aged 0–16 years, from four general population
studies were used and were the only data available from several countries. However, it
was challenging to analyze risk factors for children separately from adults in these studies.
The quality of the studies varied between countries, as well as within the same country.
Studies showed that protective levels of HbsAb antibodies decrease with age after vaccine
introduction [30,43]; however, most of the studies included in this review did not report
prevalence by age group.

5. Conclusions

In conclusion, this study using the most recent data available estimated HBV preva-
lence in children aged 0–16 years in West Africa, revealing a decrease in prevalence over
the past two decades; yet, a persistently high prevalence in high-risk child populations
still exists. The studies are robust and cover periods before and after the introduction
of HepB vaccination in different West African countries. The meta-analysis identified
wide variation in HBV prevalence, depending on the country, as well as in subgroups of
HBV/HIV co-infected children, children born to HBsAg-positive mothers, and vaccinated
or unvaccinated children. Overall, pooled prevalence and pooled subgroup prevalence
remain moderate in West Africa and reaffirm the likely impact of newborn HepB vaccina-
tion. The study reinforces the need to implement HepB-BD and screening and prophylaxis
of HBV in pregnant women. These interventions are essential to prevent mother-to-child
transmission in order to achieve the WHO goal of targeted HBV elimination.

Supplementary Materials: The following supporting information can be downloaded at: https:
//www.mdpi.com/article/10.3390/ijerph20054142/s1. Supplementary Data S1 HBV Prevalence in
Children, 0–16 Years Old, in West Africa; Supplementary Data S2 Nine studies included persons
living with HIV (PLWH); Supplementary Data S3 Before and after sensititve analysis.

Author Contributions: Conceptualization, D.B.F.; methodology, D.B.F., M.I.K. and A.M.S.; software,
D.B.F., M.I.K. and Y.C.; validation, D.B.F., A.M.S. and J.L.H.; formal analysis, D.B.F.; investigation,
D.B.F., A.M.S. and B.D.; data curation, D.B.F., A.M.S. and M.I.K.; writing—original draft preparation,
D.B.F., A.M.S., M.I.K., J.L.H., R.L.M. and C.A.H.; writing—review and editing, D.B.F., A.M.S., M.M.,
M.I.K., B.D., Y.C., S.M.M., C.A.H., A.I.M., M.S., J.G., M.H.E.-S., L.M.-J., R.L.M., M.D. and J.L.H.;
visualization, D.B.F., A.M.S., M.M., M.I.K., B.D., Y.C., S.M.M., C.A.H., A.I.M., M.S., J.G., M.H.E.-S.,
L.M.-J., R.L.M., M.D. and J.L.H.; supervision, J.L.H., S.M.M., M.M., A.I.M., M.S., J.G., L.M.-J., M.H.E.-S.
and M.D.; project administration, D.B.F.; funding acquisition, D.B.F. All authors have read and agreed
to the published version of the manuscript.

Funding: This research was funded by Fogarty International Center, grant number: K43TW011957.
Fogarty International Center (D43CA260658, D43TW010350, D43TW010543), and ANRS-MIE22295,
The content is solely the responsibility of the authors.

Institutional Review Board Statement: Not applicable.

Informed Consent Statement: Not applicable.

Data Availability Statement: The data presented in this study are available on request from the
corresponding author.

Acknowledgments: The authors are grateful to Northwestern University’s Institute for Global Health
program, the National Institutes of Health and the HBNU Consortium, the Agence Nationale de la
Recherche sur le SIDA et les Maladies Infectieuses Emergentes (ANRS MIE) for her support through
the Laboratory of virology Saint-Antoine Hospital in Paris, France and the University of Sciences,
Techniques and Technologies of Bamako (USTTB), Mali.

Int. J. Environ. Res. Public Health 2023, 20, 4142 17 of 20

Conflicts of Interest: The authors declare no conflict of interest.

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