Study selection
Initially, a total of 2729 studies were identified from the databases and manual searching. From this, 1310 of the studies were removed due to duplication. The remaining 1419 articles were screened by their title and abstract and 1312 of the studies were excluded. Further, 107 full-text articles were refined and 47 of them were excluded due to being unrelated to the current study, studies on immigrants, review articles, studies conducted before 2010, and studies on immunization. Finally, a total of 60 [20, 29-87] studies were fulfilled the inclusion criteria and enrolled in the study [Fig. 1].
Characteristics of included studies
A total of 60 articles were included in this systematic review and meta-analysis, with an overall sample size of 106125 that conducted on the prevalence of HBV in Ethiopia. All the included studies were cross-sectional study designs and the most recent was conducted in 2019. Regarding regional coverage of HBV prevalence studies, more than half of the studies were obtained from Amhara region 22 (36.7%) [20, 29, 31, 36-38, 44, 46, 49, 50, 53, 58, 62, 63, 67-69, 71, 75, 78, 79, 82], Oromia region 12(20%) [32, 34, 41, 47, 48, 56, 60, 61, 64, 83, 85, 87], and Southern Nations, Nationalities and Peoples Region (SNNPR) 9(15%) [30, 43, 52, 65, 66, 70, 74, 76, 86]. The sample size across the studies was ranged from 108 [53] to 35435 [44] obtained from the Amhara region. In addition, the qualities of each of the included studies was evaluated using the nine items risk of bias assessment tool (Table 1).
Table 1 Characteristics of the included studies in the systematic review and meta-analysis for the prevalence of hepatitis B virus in Ethiopia, 2019.
First author, year
|
P. year
|
Region
|
Study group
|
Sampling technique
|
Sample
|
HBsAg +
|
D. method
|
Quality
|
Abate M., et al [80]
|
2016
|
Somali
|
Blood donor
|
Entire sampling
|
2752
|
166
|
ELISA
|
Good
|
Abera B., et al [79]
|
2017
|
Amhara
|
HIV positive children
|
Random sampling
|
253
|
5
|
ELISA
|
Good
|
Abera B., et al [78]
|
2014
|
Amhara
|
Apparently healthy
|
Random sampling
|
481
|
15
|
RDT
|
Good
|
Akalu GT., et al [77]
|
2016
|
SAC
|
Healthcare workers
|
Convenient sampling
|
313
|
55
|
IA
|
Poor
|
Amsalu A., et al [76]
|
2018
|
SNNPR
|
Pregnant women
|
Consecutive sampling
|
475
|
34
|
ELISA
|
Good
|
Anagaw B., et al [75]
|
2012
|
Amhara
|
Waste handlers
|
Unknown
|
200
|
6
|
RDT
|
Good
|
Asfaw MA., et al [74]
|
2018
|
SNNPR
|
VCT
|
Random sampling
|
331
|
29
|
RDT
|
Good
|
Ataro Z., et al [73]
|
2018
|
SAC
|
Blood donors
|
Entire sampling
|
6376
|
298
|
ELISA
|
Good
|
Ayele AG., et al [72]
|
2013
|
SAC
|
Chronic liver diseases
|
Convenient sampling
|
120
|
43
|
RDT
|
Poor
|
Balew M., et al [71]
|
2014
|
Amhara
|
HIV positive
|
Random sampling
|
395
|
24
|
RDT
|
Poor
|
Belayneh F., [70]
|
2015
|
SNNPR
|
HIV positive adult
|
Consecutive sampling
|
348
|
24
|
RDT
|
Good
|
Betela B., et al [87]
|
2018
|
Oromia
|
General population
|
Random sampling
|
1343
|
146
|
RDT
|
Poor
|
Biadgo B., et al [69]
|
2017
|
Amhara
|
Blood donors
|
Entire sampling
|
2294
|
121
|
ELISA
|
Good
|
Bialfew Y., et al [68]
|
2018
|
Amhara
|
Blood donors
|
Consecutive sampling
|
403
|
19
|
ELISA
|
Good
|
Birku T., et al [67]
|
2015
|
Amhara
|
Military personnel
|
Random sampling
|
403
|
17
|
RDT
|
Good
|
Bisetegen FS., et al [66]
|
2016
|
SNNPR
|
Blood donors
|
Consecutive sampling
|
390
|
11
|
ELISA
|
Good
|
Chernet A., et al [65]
|
2017
|
SNNPR
|
Pregnant women
|
Entire sampling
|
289
|
10
|
RDT
|
Good
|
Dabsu R., et al [64]
|
2014
|
Oromia
|
Pregnant women
|
Convenient sampling
|
421
|
10
|
RDT
|
Good
|
Demsiss W., et al [63]
|
2018
|
Amhara
|
Students
|
Random sampling
|
422
|
17
|
ELISA
|
Good
|
Deressa T., et al [20]
|
2017
|
Amhara
|
HIV positive
|
Random sampling
|
308
|
17
|
PCR
|
Good
|
Deressa T., et al [62]
|
2018
|
Amhara
|
Blood donors
|
Entire sampling
|
8460
|
102
|
ELISA
|
Poor
|
Desalegn Z., et al [84]
|
2013
|
SAC
|
Healthcare workers
|
Convenient sampling
|
254
|
6
|
IA
|
Good
|
Desalegn Z., et al [83]
|
2016
|
Oromia
|
Pregnant women
|
Entire sampling
|
202
|
11
|
ELISA
|
Good
|
Erena AN., et al [61]
|
2014
|
Oromia
|
General population
|
Random sampling
|
353
|
26
|
IA
|
Good
|
G/micheal A., et al [60]
|
2013
|
Oromia
|
Healthcare workers
|
Random sampling
|
220
|
9
|
RDT
|
Poor
|
G/egziabher D., et al [59]
|
2016
|
SAC
|
General population
|
Entire sampling
|
482
|
102
|
RDT
|
Poor
|
G/mariam AA., et al [58]
|
2019
|
Amhara
|
Healthcare professional
|
Entire sampling
|
332
|
15
|
RDT
|
Good
|
Habte Y., et al [57]
|
2016
|
SAC
|
Blood donors
|
Entire sampling
|
4157
|
155
|
ELISA
|
Good
|
Hebo HJ., et al [56]
|
2019
|
Oromia
|
Healthcare workers
|
Random sampling
|
240
|
6
|
ELISA
|
Good
|
Heyredin I., et al [55]
|
2019
|
Mixed
|
Blood donors
|
Consecutive sampling
|
500
|
33
|
ELISA
|
Good
|
Kabato AA., et al [86]
|
2016
|
SNNPR
|
Blood donors
|
Entire sampling
|
359
|
17
|
ELISA
|
Good
|
Kebede W., et al [85]
|
2017
|
Oromia
|
Prisoners
|
Random sampling
|
156
|
9
|
ELISA
|
Good
|
Mekonnen A., et al [54]
|
2015
|
SAC
|
Waste handlers
|
Random sampling
|
252
|
9
|
ELISA
|
Good
|
Mekonnen D., et al [53]
|
2014
|
Amhara
|
Diabetes mellitus
|
*
|
108
|
4
|
RDT
|
Poor
|
Metaferia Y., et al [52]
|
2016
|
SNNPR
|
Pregnant women
|
Convenient sampling
|
269
|
21
|
ELISA
|
Good
|
Mezgebo TA., et al [81]
|
2018
|
Tigray
|
Pregnant women
|
*
|
328
|
18
|
IA
|
Good
|
Mohammed Y., et al [51]
|
2016
|
Somali
|
Blood donors
|
Entire sampling
|
4224
|
460
|
ELISA
|
Good
|
Molla S., et al [50]
|
2015
|
Amhara
|
Pregnant women
|
Random sampling
|
384
|
17
|
RDT
|
Good
|
Negash M., et al [49]
|
2019
|
Amhara
|
Blood donors
|
Entire sampling
|
310
|
18
|
ELISA
|
Good
|
Negero A., et al [48]
|
2011
|
Oromia
|
VCT
|
Entire sampling
|
384
|
22
|
RDT
|
Good
|
Schonfeld A., et al [47]
|
2018
|
Oromia
|
Pregnant women
|
Consecutive sampling
|
580
|
31
|
RDT
|
Good
|
Seid M., et al [46]
|
2014
|
Amhara
|
Pregnant women
|
Random sampling
|
385
|
19
|
ELISA
|
Good
|
Shiferaw E., et al [44]
|
2019
|
Amhara
|
Blood donors
|
Entire sampling
|
35435
|
230
|
ELISA
|
Good
|
Shiferaw Y., et al [45]
|
2011
|
SAC
|
Waste Handlers
|
Random sampling
|
252
|
9
|
ELISA
|
Good
|
Shimelis T., et al [43]
|
2017
|
SNNPR
|
HIV positive
|
*
|
477
|
30
|
RDT
|
Good
|
Shure W., et al [42]
|
2018
|
SAC
|
Barbers
|
Convenient sampling
|
400
|
15
|
ELISA
|
Good
|
Taye S., et al [41]
|
2014
|
Oromia
|
Chronic hepatitis
|
Entire sampling
|
358
|
80
|
RDT
|
Poor
|
Tegegne D., et al [40]
|
2014
|
SAC
|
Pregnant women
|
*
|
265
|
8
|
ELISA
|
Good
|
Teklemariam Z., et al [40]
|
2018
|
Harari
|
Blood donors
|
Entire sampling
|
4107
|
167
|
ELISA
|
Good
|
Tesfa H., et al [38]
|
2013
|
Amhara
|
Clinically suspected
|
Entire sampling
|
2684
|
382
|
RDT
|
Good
|
Tessema B., et al [37]
|
2010
|
Amhara
|
Blood donors
|
Entire sampling
|
6361
|
299
|
ELISA
|
Good
|
Tigabu A., et al [36]
|
2019
|
Amhara
|
Blood donors
|
Entire sampling
|
5983
|
244
|
ELISA
|
Good
|
Tiruye G., et al [35]
|
2018
|
Harari
|
Pregnant women
|
Random sampling
|
320
|
20
|
ELISA
|
Good
|
Umare A., et al [34]
|
2016
|
Oromia
|
Pregnant women
|
Consecutive sampling
|
318
|
22
|
ELISA
|
Poor
|
Weldemhret L., et al [33]
|
2016
|
Tigray
|
HIV positive
|
*
|
508
|
30
|
ELISA
|
Good
|
Wondimeneh Y., et al [82]
|
2013
|
Amhara
|
HIV positive
|
Consecutive sampling
|
400
|
20
|
RDT
|
Good
|
Yami A., et al [32]
|
2011
|
Oromia
|
Blood donors
|
Entire sampling
|
6063
|
126
|
ELISA
|
Good
|
Yizengaw E., et al [31]
|
2018
|
Amhara
|
Healthcare workers
|
Random sampling
|
388
|
10
|
ELISA
|
Good
|
Yohanes T., et al [30]
|
2016
|
SNNPR
|
Pregnant women
|
Random sampling
|
232
|
10
|
ELISA
|
Good
|
Zenebe Y., et al [29]
|
2014
|
Amhara
|
Pregnant women
|
Random sampling
|
318
|
12
|
ELISA
|
Good
|
Key: SAC: Self-Administrative City; SNNPR: Southern Nations, Nationalities and Peoples’ Region; ELISA: Enzyme-Linked Immunosorbent Assay; RDT: Rapid Diagnostic Test; IA: Immunoassay; *: not stated; VCT: volunteer for counseling and testing
Prevalence of HBV in Ethiopia
There was a wide HBV prevalence variation among included studies which is ranged from 1% in Amhara region to 36% in Addis Ababa city. Based on the random-effects model, the overall pooled prevalence among 106125 was 6% (95% CI: 5% to 6%) with heterogeneity index (I2) of 97.77% (p<0.001) (Fig. 2).
Subgroup analysis
Since this meta-analysis exhibited a considerable heterogeneity, subgroup analysis was done using study group, study quality, region/ city where the studies were conducted, year of publication, data collection year, sampling technique, screening method, and the setting was considered to identify the possible sources of heterogeneity among the studies. The subgroup analysis indicated that the heterogeneity level was slightly reduced among pregnant women (I2=52.2%), HIV positive study participants (I2=64.59%), studies conducted in SNNPR (I2=67.13%), studies conducted using probability sampling technique (I2=80.13%), and among studies those did not clearly indicated their sampling techniques (I2=% 41.91%). Geographically, the highest and the lowest prevalence of HBV were obtained from the Addis Ababa city 10% (95% CI: 6%, 15%) and Amhara region 4% (95% CI: 3%, 5%), respectively. Studies conducted on nonprobability sampling accounted for the highest 7% (95% CI: 5%, 9%) followed by studies conducted through a survey. Concerning screening techniques, studies conducted using ELISA accounted for the least prevalence estimate of 4% (95% CI: 4%, 5%) (Table 2).
Table 2 Subgroup analysis of the HBV pooled prevalence estimation in Ethiopia, 2019.
Moderator variables
|
Variable category
|
Included studies
|
Prevalence % (95% CI)
|
I2 %
|
I2 % P-value
|
|
Blood donor
|
16
|
4 (0.03, 0.06)
|
98.99
|
0.00
|
|
Pregnant women
|
14
|
5 (0.04, 0.06
|
52.20
|
0.01
|
Study group
|
Healthcare worker
|
6
|
5 (0.05, 0.08)
|
89.47
|
0.00
|
|
HIV positive
|
7
|
5 (0.04, 0.07)
|
64.59
|
0.01
|
|
Others
|
17
|
9 (0.06, 0.11)
|
95.69
|
0.00
|
Study quality
|
Good quality
|
50
|
5 (0.04, 0.06)
|
97.74
|
0.00
|
Poor quality
|
10
|
12 (0.07, 017)
|
98.12
|
0.00
|
|
Amhara
|
22
|
4 (0.03, 0.05)
|
97.95
|
0.00
|
|
Oromia
|
12
|
6 (0.04, 0.09)
|
95.08
|
0.00
|
Region/ city
|
SNNPR
|
9
|
6 (0.04, 0.07)
|
67.13
|
0.00
|
|
Addis Ababa city
|
8
|
10 (0.06, 0.15)
|
96
|
0.00
|
|
Others
|
9
|
6 (0.04, 0.07)
|
95.77
|
0.00
|
|
2010-2012
|
5
|
4 (0.02, 0.05)
|
94.44
|
0.00
|
Year of publication
|
2013-2015
|
18
|
7 (0.05, 0.09)
|
94.85
|
0.00
|
|
2016-2019
|
37
|
6 (0.05, 0.07)
|
98.02
|
0.00
|
|
2010-2012
|
12
|
5 (0.03, 0.06)
|
92.28
|
0.00
|
Year of study
|
2013-2015
|
26
|
5 (0.05, 0.06)
|
85.59
|
0.00
|
|
2016-2019
|
12
|
6 (0.04, 0.07)
|
89.54
|
0.00
|
|
Probability
|
20
|
5 (0.04, 0.06)
|
80.13
|
0.00
|
Sampling techniques
|
Non-probability
|
14
|
7 (0.05, 0.09)
|
89.56
|
0.00
|
Survey
|
20
|
6 (0.05, 0.07)
|
99.07
|
0.00
|
|
Not stated
|
6
|
5 (0.03, 0.06)
|
41.91
|
0.105
|
|
ELISA
|
34
|
4 (0.04, 0.05)
|
97.98
|
0.00
|
Diagnosis method
|
RDT
|
21
|
8 (0.06, 0.10)
|
95.07
|
0.00
|
|
IA
|
4
|
8 (0.03, 0.13)
|
93.20
|
0.00
|
Setting
|
Urban
|
39
|
6 (0.05, 0.07)
|
98.41
|
0.00
|
Mixed
|
21
|
5 (0.05, 0.06)
|
90.93
|
0.00
|
Key: ELISA: Enzyme-Linked Immunosorbent Assay; IA: Immunoassay; RDT: Rapid Diagnostic Test; SNNPR; Southern Nations, Nationalities and Peoples Region
Meta-regression and sensitivity analysis
A meta-regression analysis was done on the categorical variables including year of study, year of publication, study group, region, sample size, sampling technique, quality score, and screening methods. Among these variables, year of data collection was borderline significant. The remaining covariates including region/ city (p=0.04), study group (p=0.005), screening method (p=0.017) and quality of papers (p=0.001) were significantly associated with HBV pooled prevalence (Table 3). Sensitivity analysis was performed by removing a single study from the analysis in order to ensure the stability of the overall effect estimate. The result indicated that removing a single study from the analysis did not significantly influence the pooled estimate (Additional file 2).
Table 3 Meta-regression analysis of factors for the heterogeneity of HBV prevalence in Ethiopia, 2019.
Moderator
|
Coefficient
|
Std. Error
|
P-value
|
Adjusted R2 (%)
|
Data collection year
|
.1547288
|
.0859943
|
0.077
|
4.07%
|
Region/ city
|
.1328385
|
.0631128
|
0.040
|
5.98%
|
Study group
|
.1623181
|
.0559312
|
0.005
|
13.81%
|
Screening method
|
.3274201
|
.132906
|
0.017
|
9.54%
|
Quality of papers
|
.8060166
|
.2361892
|
0.001
|
16.66%
|
Publication bias and small study effects
The presence of publication bias was evaluated using funnel plots and Egger’s test. Each point in funnel plots represents a separate study and asymmetrical distribution indicates the presence of publication bias [5]. First, studies’ effect sizes were plotted against their standard errors and the visual evaluation of the funnel plot indicated no publication bias as the graph appear symmetrical (Fig. 3). The subjective evidence from the funnel plot was objectively confirmed using the Egger’s weighted regression statistics. According to the symmetry assumption, the p-value of 0.747 declares the absence of small study effects among the included studies.