Genetic diversity and occult hepatitis B infection in Africa: A comprehensive review

Table 1 Distribution of occult hepatitis B infection prevalence in the southern region of Africa

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	DNA limit of detection	Effective	HBV genotype
Peliganga et al[47]	2021	Angola	Blood donors	2.9	Cross-sectional	Real-time PCR	ND	500
Mbangiwa et al[67]	2018	Botswana	Pregnant women with/without HIV	6.6	Prospective study	COBAS AmpliPrep	ND	622	D3, A1, E
Ryan et al[72]	2017	Botswana	HIV patient	26.5	ND	COBAS AmpliPrep	ND	272
Mabunda et al[51]	2020	Mozambique	Blood donors	0.98	Cross-sectional	PCR	20 UI/mL	1435
Carimo et al[69]	2018	Mozambique	ART naïve HIV patient	8.3	Cross-sectional	Real-time PCR	ND	206
Sondlane et al[30]	2016	South Africa	Healthcare workers	6.7	Descriptive study	Real-time PCR	ND	314
Amponsah-Dacosta et al[119]	2015	South Africa	Post-vaccination	66 and 70.4	ND	Real-time PCR	ND	62 and 139
Powell et al[81]	2015	South Africa	HIV patient	13.5	ND	Real-time PCR	250 copies/mL	394
Hoffmann et al[65]	2014	South Africa	Pregnant women with HIV	1.71	Case-control study	Real-time PCR	20 IU/ mL	175
Ayuk et al[82]	2013	South Africa	HIV/HBV Co-infection	33.7	Unmatched study	Nested PCR	ND	181
Bell et al[68]	2012	South Africa	ART naive HIV	3.79	Cohort	Real-time PCR	20 IU/ mL	79
Mayaphi et al[83]	2012	South Africa	HIV/HBV Co-infection HIV patient	3.5 in AIDS 1 in no AIDS	Cross-sectional	Nested PCR	ND	200/200
Firnhaber et al[66]	2009	South Africa	HIV patient	88.4	ND	Real-time PCR	ND	53

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; HIV: Human immunodeficiency virus; ND: Not defined; HCV: Hepatitis C virus; ART: Antiretroviral therapy.

Table 2 Distribution of occult hepatitis B infection prevalence in the northern region of Africa

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	DNA limit of detection	Effective	HBV genotype
Amer et al[106]	2020	Egypt	Haemodialysis patients with HCV	33.8	ND	Real-time PCR	ND	325
Abdel-Maksoud et al[104]	2019	Egypt	Haemodialysis	7.3	Cohort	Nested PCR	30 copies/mL	150
Elmaghloub et al[29]	2017	Egypt	Healthcare workers	5.3	Cross-sectional	Nested PCR	ND	132
Omar et al[93]	2017	Egypt	HCV patients with/without schistosomiasis	With schistosomias 12.8% without schistosomias 8.5%	ND	Real-time PCR	ND	200
Esmail et al[40]	2016	Egypt	Haemodialysis without HCV	8.3	ND	Real-time PCR	ND	144	B, C, D
Mahmoud et al[87]	2016	Egypt	HCV patients	18	Cross-sectional	Real-time PCR	ND	100
Elbedewy et al[114]	2015	Egypt	Patient with malignant tumors of the lymphatic system	13.89	Cross-sectional	Real-time PCR	12 IU/mL	72
Elsawaf et al[21]	2015	Egypt	ART in chronic hepatitis C patients	90.9	ND	Nested PCR	ND	11
Helaly et al[108]	2015	Egypt	Haemodialysis	32	Cross-sectional	Real-time PCR	ND	100
Kishk et al[58]	2015	Egypt	Blood donors	22.7	ND	Real-time PCR	100 copies/mL	343	D
Mandour et al[109]	2015	Egypt	HCV and Haemodialysis	8.5% in CHC and 1.8% in HD	ND	Nested PCR	ND	210 et 165
Raouf et al[92]	2015	Egypt	HCV positive cancer children	32	case–control study	Nested PCR	ND	50
Elrashidy et al[20]	2014	Egypt	Diabetic children and adolescents following hepatitis B vaccination	0	ND	Nested PCR	100 copies/mL	170
Kishk et al[88]	2014	Egypt	CHC patient	7.5	ND	Real-time PCR	ND	162	D
El-Ghitany et al[86]	2013	Egypt	Blood donors with hepatitis C	4.16 (3.2 HVC+ et 5.1 HCV-)	case–control study	Real Time PCR	45 copies/mL	504
Elkady et al[113]	2013	Egypt	Hematological malignant patients	5.66	ND	Real-time PCR	20 IU/mL	18	D1
Said et al[48]	2013	Egypt	Blood donors	1.64	Cross-sectional	Real-time PCR	3.8 IU/mL	3167
Taha et al[42]	2013	Egypt	HCV patients with/without hepatocellular carcinoma	22.5 (17.5 with CHC 5 without CHC)	Cross-sectional	Nested PCR	ND	40	D, B, C, A
Youssef et al[36]	2013	Egypt	Children with acute HBV	29.16	ND	Real-time PCR	ND	24	D (D1, D2)
Abu El Makarem et al[105]	2012	Egypt	Haemodialysis with/without HCV	4.1	ND	Real-time PCR	6 IU/mL	145
Elgohry et al[107]	2012	Egypt	Haemodialysis	26.8	ND	PCR	ND	93
Shaker et al[116]	2012	Egypt	Thalassemic children	32.5	Prospective study	Real Time PCR	ND	80
Hassan et al[41]	2011	Egypt	Hepatocellular carcinoma patient	22.5	ND	Nested PCR	ND	40	D, B, A, C
Selim et al[89]	2011	Egypt	HCV patients	38.3	ND	Real-time PCR	45 copies/mL	60
Antar et al[59]	2010	Egypt	Blood donors	0.48	ND	Real-time PCR	ND	1021
Emara et al[90]	2010	Egypt	HCV patients	3.9	Cross-sectional	Real-Time PCR	12 IU/mL	155
El-Sherif et al[91]	2009	Egypt	HCV patients	16	ND	Real-Time PCR	30 copies/mL	100
Said et al [118]	2009	Egypt	Children with malignant hematological disorders	21	case–control study	Nested PCR	ND	100
Youssef et al[43]	2009	Egypt	Patient with elevated transaminases	64.8	ND	Nested PCR	ND	119	C (C2), D (D1)
El-Zayadi et al[49]	2008	Egypt	Blood donors	1.26	ND	PCR	ND	712
El-Sherif et al[50]	2007	Egypt	Blood donors	1.3	ND	PCR	ND	150

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; ND: Not defined; HCV: Hepatitis C virus; ART: Antiretroviral therapy; CHC: Chronic hepatitis C; HD: Haemodialysis.

Table 3 Distribution of occult hepatitis B infection prevalence in the central region of Africa

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	DNA limit of detection	Effective	HBV genotype
Kengne et al[6]	2021	Cameroun	Blood donors	9.83	Cross-sectional et prospective	PCR	ND	193
Fopa et al[57]	2019	Cameroun	Blood donors	2.3	ND	Nested PCR	ND	1162
Gachara et al[73]	2017	Cameroun	HIV patient	5.9	Cross-sectional	Nested PCR	ND	337
Bivigou-Mboumba et al[75]	2018	Gabon	HIV patient	17.5	Cross-sectional	Real-time PCR	50 IU/mL	137
Bivigou-Mboumba et al[76]	2016	Gabon	HIV patient	8	Cross-sectional	Real-time PCR	100 IU/mL	762	A E

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; HIV: Human immunodeficiency virus; ND: Not defined.

Table 4 Distribution of occult hepatitis B infection prevalence in the eastern region of Africa

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	DNA limit of detection	Effective	HBV genotype
Gissa et al[99]	2022	Ethiopia	Patients with chronic liver disease of unidentified cause	5.56	Prospective	Real-Time PCR	15 IU/mL	36
Ayana et al[74]	2020	Ethiopia	HIV negative/positive isolated antiHBc	5.6	ND	Real-Time PCR	ND	306
Meier-Stephenson et al[38]	2020	Ethiopia	Pregnant women	20.3	Prospective	Nested PCR	ND	182	D, C
Patel et al[44]	2020	Ethiopia	HIV patient	19.1	Cross-sectional	Nested PCR	ND	291	D, E, A, C
Salyani et al[70]	2021	Kenya	HIV patient ART naïve	5.3	Cross-sectional	COBAS AmpliPrep	20 UI/mL	208
Aluora et al[37]	2020	Kenya	Blood donors	2.3	Cross-sectional	Nested PCR	ND	300	A
Jepkemei et al[28]	2020	Kenya	Populations with high risk of HBV infection	18.7	Cohort	Real-time PCR	ND	99
Rusine et al[80]	2013	Rwanda	HIV patient	42.9	Prospective study	PCR	ND	218
Ahmed et al[112]	2022	Sudan	Patients with chronic renal failure	22	Cross-sectional	Nested PCR	ND	188
Mustafa et al[101]	2020	Sudan	Renal Transplant Patients	51.4	ND	Real-time PCR	ND	100	A, D, E
Bashir and Hassan[33]	2019	Sudan	Febrile malaria Patients	18.2	ND	Real-time PCR	ND	88
Sahr Hagmohamed et al[111]	2019	Sudan	Haemodialysis	15.9	Cross-sectional	PCR	ND	88
Majed et al[100]	2018	Sudan	Haemodialysis	0	Cross-sectional	PCR	ND	88
Hassan et al[55]	2017	Sudan	Blood donors	7.9	ND	Nested PCR	ND	177
Mohammed et al[110]	2015	Sudan	Haemodialysis	3.3	ND	PCR	ND	91
Mudawi et al[84]	2014	Sudan	HIV patient	11,07	Cross-sectional	Real-time PCR	ND	316
Yousif et al[39]	2014	Sudan	HIV patient	55.5	ND	Real-time PCR	ND	18	D, E, A, D/E
Abd El Kader Mahmoud et al[46]	2013	Sudan	Blood donors	38	ND	Real-time PCR	ND	100
Mahgoub et al[56]	2011	Sudan	Blood donors	4.6	ND	Nested PCR	ND	129
Meschi et al[34]	2010	Tanzania	Febrile patient	7.7	Cross-sectional	Real-time PCR	ND	13

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; HIV: Human immunodeficiency virus; ND: Not defined; ART: Antiretroviral therapy.

Table 5 Distribution of occult hepatitis B infection prevalence in the western region of Africa

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	DNA limit of detection	Effective	HBV genotype
Ky/Ba et al[25]	2021	Burkina Faso	Blood donors	4	Cross-sectional	Real-time PCR	ND	300
Diarra et al[26]	2018	Burkina Faso	General population	7.3	ND	Real-time PCR	ND	219	E and A3
Somda et al[24]	2016	Burkina Faso	Blood donors	32.8	Prospective study	Real-time PCR	ND	160
Ndow et al[27]	2022	Gambia	General population	18.3	Case-control study	Nested PCR	5 IU/mL	82
Gouas et al[97]	2012	Gambia	Patient with Cirrhosis and HCC	15% cirrhosis et 24% with HCC	Case–control study	PCR	ND	34 et 88	E, D, A
Attiku et al[77]	2021	Ghana	HIV/HBV co-infected patients	30.8	Longitudinal purposive study	Real-time PCR	2 copies/mL	13
Attia et al[78]	2012	Ivory Coast	HIV patient	21.3	Cross-sectional	COBAS Amplicor HBV	6 UI/mL	188
Fasola et al[60]	2021	Nigeria	Blood donors	1	Cross-sectional	Nested PCR	1 IU/mL	100
Akintule et al[52]	2018	Nigeria	Blood donors	8.7	ND	Nested PCR	ND	206	83.3% A 11.1% no A
Olotu et al[53]	2016	Nigeria	Blood donors	5.4	Cross-sectional	Real-time PCR	20 IU/mL	354
Oluyinka et al[61]	2015	Nigeria	Blood donors	17	ND	Real-time PCR	ND	492
Nna et al[54]	2014	Nigeria	Blood donors	8	ND	Nested PCR	ND	100
Opaleye et al[79]	2014	Nigeria	HIV patient	11.8	ND	PCR	ND	188

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; HIV: Human immunodeficiency virus; ND: Not defined; HCC: Hepatocellular carcinoma.

Table 6 Distribution of hepatitis B virus genotypes involved in occult hepatitis B infection

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	Effective	HBV genotype
Mbangiwa et al[67]	2018	Botswana	Pregnant women with/without HIV	6.6	Prospective study	COBAS AmpliPrep	622	D3, A1, E
Diarra et al[26]	2018	Burkina Faso	General population	7.3	ND	Real-time PCR	219	E and A3
Esmail et al[40]	2016	Egypt	Haemodialysis without HCV	8.3	ND	Real-time PCR	144	B, C, D
Kishk et al[58]	2015	Egypt	Blood donors	22.7	ND	Real-time PCR	343	D
Kishk et al[88]	2014	Egypt	CHC patient	7.5	ND	Real-time PCR	162	D
Elkady et al[113]	2013	Egypt	Hematological malignant patients	5.66	ND	Real-time PCR	18	D1
Taha et al[42]	2013	Egypt	HCV patients with/without hepatocellular carcinoma	22.5 (17.5 with CHC 5 without CHC)	Cross-sectional	Nested PCR	40	D, B, C, A
Youssef et al[36]	2013	Egypt	Children with acute HBV	29,16	ND	Real-time PCR	24	D (D1, D2)
Hassan et al[41]	2011	Egypt	Hepatocellular carcinoma patient	22.5	ND	Nested PCR	40	D, B, A, C
Youssef et al[43]	2009	Egypt	Patient with elevated transaminases	64.8	ND	Nested PCR	119	C (C2), D (D1)
Meier-Stephenson et al[38]	2020	Ethiopia	Pregnant women	20.3	Prospective	Nested PCR	182	D, C
Patel et al[44]	2020	Ethiopia	HIV patient	19.1	Cross-sectional	Nested PCR	291	D, E, A, C
Bivigou-Mboumba et al[76]	2016	Gabon	HIV patient	8	Cross-sectional	Real-time PCR	762	A, E
Gouas et al[97]	2012	Gambia	Patient with Cirrhosis and HCC	15% cirrhosis et 24% with HCC	case–control study	PCR	34 et 88	E, D, A
Aluora et al[37]	2020	Kenya	Blood donors	2.3	Cross-sectional	Nested PCR	300	A
Akintule et al[52]	2018	Nigeria	Blood donors	8.7	ND	Nested PCR	206	83.3% A 11.1% no A
Ibrahim et al[102]	2020	Sudan	Renal transplant patients	18	Cross-sectional	Nested PCR	100	D, A, E
Mustafa et al[101]	2020	Sudan	Renal Transplant Patients	51,4	ND	Real-time PCR	100	A, D, E
Yousif et al[39]	2014	Sudan	HIV patient	55.5	ND	Real-time PCR	18	D, E, A, D/E

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; HIV: Human immunodeficiency virus; ND: Not defined; HCV: Hepatitis C virus; CHC: Chronic hepatitis C; HCC: Hepatocellular carcinoma.

Table 7 DNA limit of detection in included studies

Ref.	Year	Countries	Patients	OBI prevalence, n (%)	Types of studies	Methods	DNA low limit of detection	Effective	HBV genotype
Abdel-Maksoud et al[104]	2019	Egypt	Haemodialysis	7.3	Cohort	Nested PCR	30 copies/mL	150
Elbedewy et al[114]	2015	Egypt	Patient with malignant tumors of the lymphatic system	13.89	Cross-sectional	Real-time PCR	12 IU/mL	72
Kishk et al[58]	2015	Egypt	Blood donors	22.7	ND	Real-time PCR	100 copies/mL	343	D
Elrashidy et al[20]	2014	Egypt	Diabetic children and adolescents following hepatitis B vaccination	0	ND	Nested PCR	100 copies/mL	170
El-Ghitany et al[86]	2013	Egypt	Blood donors with hepatitis C	4,16 (3,2 HVC+ et 5,1 HCV-)	Case–control study	Real time PCR	45 copies/mL	504
Elkady et al[113]	2013	Egypt	Hematological malignant patients	5.66	ND	Real-time PCR	20 IU/mL	18	D1
Said et al[48]	2013	Egypt	Blood donors	1.64	Cross-sectional	Real-time PCR	3.8 IU/mL	3167
Abu El Makarem et al[105]	2012	Egypt	Haemodialysis with/without HCV	4.1	ND	Real-time PCR	6 IU/mL	145
Selim et al[89]	2011	Egypt	HCV patients	38.3	ND	Real-time PCR	45 copies/mL	60
Emara et al[90]	2010	Egypt	HCV patients	3.9	Cross-sectional	Real-Time PCR	12 IU/mL	155
El-Sherif et al[91]	2009	Egypt	HCV patients	16	ND	Real-Time PCR	30 copies/mL	100
Gissa et al[99]	2022	Ethiopia	Patients with chronic liver disease of unidentified cause	5.56	Prospective	Real-Time PCR	15 IU/mL	36
Bivigou-Mboumba et al[75]	2018	Gabon	HIV patient	17.5	Cross-sectional	Real-time PCR	50 IU/mL	137
Bivigou-Mboumba et al[76]	2016	Gabon	HIV patient	8	Cross-sectional	Real-time PCR	100 IU/mL	762	A E
Ndow et al[27]	2022	Gambia	General population	18.3	Case-control study	Nested PCR	5 IU/mL	82
Attiku et al[77]	2021	Ghana	HIV/HBV co-infected patients	30.8	Longitudinal purposive study	Real-time PCR	2 copies/mL	13
Attia et al[78]	2012	Ivory Coast	HIV patient	21.3	Cross-sectional	COBAS Amplicor HBV	6 UI/mL	188
Salyani et al[70]	2021	Kenya	HIV patient ART naïve	5.3	Cross-sectional	COBAS AmpliPrep	20 UI/mL	208
Mabunda et al[51]	2020	Mozambique	Blood donors	0.98	Cross-sectional	PCR	20 UI/mL	1435
Fasola et al[60]	2021	Nigeria	Blood donors	1	Cross-sectional	Nested PCR	1 IU/mL	100
Olotu et al[53]	2016	Nigeria	Blood donors	5.4	Cross-sectional	Real-time PCR	20 IU/mL	354
Powell et al[81]	2015	South Africa	HIV patient	13.5	ND	Real-time PCR	250 copies/mL	394
Hoffmann et al[65]	2014	South Africa	Pregnant women with HIV	1.71	Case-control study	Real-time PCR	20 IU/ mL	175
Bell et al[68]	2012	South Africa	ART naive HIV	3.79	Cohort	Real-time PCR	20 IU/ mL	79

OBI: Occult hepatitis B infection; HBV: Hepatitis B virus; PCR: Polymerase chain reaction; HIV: Human immunodeficiency virus; ND: Not defined; HCV: Hepatitis C virus; ART: Antiretroviral therapy.