Seroprevalence of HIV, HBV, HCV, and HTLV among Pregnant Women in Southwestern Nigeria

Systematic review and meta-analysis of seroprevalence of human immunodeficiency virus serological markers among pregnant women in Africa, 1984-2020

BACKGROUND

Human immunodeficiency virus (HIV) is a major public health concern, particularly in Africa where HIV rates remain substantial. Pregnant women are at an increased risk of acquiring HIV, which has a significant impact on both maternal and child health.

AIM

To review summarizes HIV seroprevalence among pregnant women in Africa. It also identifies regional and clinical characteristics that contribute to study-specific estimates variation.

METHODS

The study included pregnant women from any African country or region, irrespective of their symptoms, and any study design conducted in any setting. Using electronic literature searches, articles published until February 2023 were reviewed. The quality of the included studies was evaluated. The DerSimonian and Laird random-effects model was applied to determine HIV pooled seroprevalence among pregnant women in Africa. Subgroup and sensitivity analyses were conducted to identify potential sources of heterogeneity. Heterogeneity was assessed with Cochran's Q test and I2 statistics, and publication bias was assessed with Egger's test.

RESULTS

A total of 248 studies conducted between 1984 and 2020 were included in the quantitative synthesis (meta-analysis). Out of the total studies, 146 (58.9%) had a low risk of bias and 102 (41.1%) had a moderate risk of bias. No HIV-positive pregnant women died in the included studies. The overall HIV seroprevalence in pregnant women was estimated to be 9.3% [95% confidence interval (CI): 8.3-10.3]. The subgroup analysis showed statistically significant heterogeneity across subgroups (P < 0.001), with the highest seroprevalence observed in Southern Africa (29.4%, 95%CI: 26.5-32.4) and the lowest seroprevalence observed in Northern Africa (0.7%, 95%CI: 0.3-1.3).

CONCLUSION

The review found that HIV seroprevalence among pregnant women in African countries remains significant, particularly in Southern African countries. This review can inform the development of targeted public health interventions to address high HIV seroprevalence in pregnant women in African countries.

Seroprevalence and Associated Factors of HBV and HCV among Pregnant Women Attending Antenatal Care at Debre Tabor Comprehensive Specialized Hospital, Northwest Ethiopia: A Cross-Sectional Study

Background

Infections with the hepatitis B virus (HBV) and the hepatitis C virus (HCV) are worldwide problems that particularly place a heavy burden on developing nations. HBV and HCV infections during pregnancy have a high rate of vertical transmission and harmful consequences for both the mother and the child. Therefore, this study was carried out to assess the seroprevalence and associated factors of HBV and HCV infections among pregnant women attending antenatal care at Debre Tabor Comprehensive Specialized Hospital in Ethiopia.

Methods

A cross-sectional study was conducted from March 15th to September 16th, 2022, at the Debre Tabor Comprehensive Specialized Hospital antenatal care clinic. Five milliliters of venous blood were collected from 422 pregnant women selected using a simple random sampling method. Data on sociodemographic characteristics and risk factors were collected using a prestructured questionnaire. A chi-square test, bivariate, and multivariate analyses were used to evaluate the association between dependent and independent variables. p values less than 0.05 were considered statistically significant.

Results

The seroprevalence of HBV and HCV infections was found to be 13% and 0.5%, respectively. Undertaking blood transfusion (AOR = 14.2, CI = 5.81-34.526, p = 0.001), tattooing (AOR = 3.99, CI = 1.1-14.36, p = 0.034), and dental therapy (AOR = 4.9, CI = 1.41-17.025, p = 0.012) were significantly associated with HBV infection.

Conclusion

HBV infection in pregnant women was shown to have a high endemicity (13%) in this investigation, whereas the seroprevalence of HCV infection was low (0.5%). HBV infection was significantly associated with a history of blood transfusions, tattooing, and dental therapy. Screening pregnant women for HBV and HCV infections and providing effective therapy would ensure better outcomes for the newborn. In addition, health education must be used to increase knowledge of screening and modes of transmission.

A Systematic Review and Meta-Analysis of the Prevalence of Triplex Infections (Combined Human Immunodeficiency Virus, Hepatitis B Virus, and Hepatitis C Virus) among Pregnant Women in Nigeria

Objective

We systematically identified the prevalence of triplex infections (combined human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV)) in pregnancy.

Methods

To gather information on the frequency of triplex infections, we searched the databases of PubMed, CINAHL, and Google Scholar. Without regard to language, we utilized search terms that covered HIV, HBV, HCV, and pregnancy. Pregnant women with triplex infections of HIV, HBV, and HCV were included in studies that also examined the prevalence of triplex infections. Review Manager 5.4.1 was employed to conduct the meta-analysis. Critical appraisal and bias tool risk data were provided as percentages with 95% confidence intervals (95% CIs), and I² was used as the statistical measure of heterogeneity. The checklist was created by Hoy and colleagues. The study protocol was registered on PROSPERO, under the registration number CRD42020202583.

Results

Eight studies involving 5314 women were included. We identified one ongoing study. Pooled prevalence of triplex infections was 0.03% (95% CI: 0.02-0.04%) according to meta-analysis. Subgroup analysis demonstrated a significantly high prevalence of 0.08% (95% CI: 0.06-0.10%; 3863 women) in HIV-positive population than 0.00% (95% CI:-0.00-0.00; 1451 women; P < 0.001) in general obstetric population. Moreover, there was a significant difference in the pooled prevalence between studies published between 2001 and 2010 and between 2011 and 2021 (0.14% (95% CI: 0.12 to 0.16 versus 0.03% (95% CI: 0.02 to 0.04%; P < 0.001))) and participants recruited in the period between 2001 and 2011 and between 2012 and 2021 (0.13% (95% CI: 0.05 to 0.21; p=0.002 versus 0.00% (95% CI: -0.00 to 0.00%; p=1.00))), respectively.

Conclusion

The combined prevalence of prenatal triplex infections was 0.03%, with rates notably higher among the group of pregnant women who were HIV-positive and during the recruitment period that took place before 2012. This prevalence still necessitates screening for these infections as necessary.

Seroepidemiology of HBV, HCV, HIV, HTLV, and CMV in Pregnant Women Referring to Sari Birth Cohort

Background

Congenital infections are among the most important conditions threatening human fetal health, the majority of which are caused by viral agents. Screening pregnant women for viral infections is essential because such infections can cause serious consequences for both the mother and the infant. So, this study aimed to serologically investigate sexually transmitted viral infections in pregnant women and also find the association between the prevalence of viral infections and epidemiological parameters in pregnant women of Sari, Iran.

Materials and Methods

This descriptive, observational study was performed in pregnant women referring to Sari Birth Cohort Center between 2018 and 2020. A total of 1092 blood samples were investigated for hepatitis B (HBV), hepatitis C (HCV), human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV), and cytomegalovirus (CMV) serological markers by enzyme-linked immunosorbent assay (ELISA).

Results

The prevalence of HBsAg positivity, HCV, HIV, and HTLV was 0.2%, 0.09%, 0.09%, and 0.2%, respectively. The percentage of participants with CMV-IgM and -IgG antibody titers above normal was 0.2% and 91.8%, respectively. Pregnant women whose educational level was bachelor's degree or lower, those who did not use a male condom before pregnancy, or those with a family history of infectious disease were found to be more likely to have HBV, HCV, HIV, HTLV, and CMV infections.

Conclusion

Family history, maternal age, pregnancy stage, and not using a male condom are among the risk factors for sexually transmitted viral infections in pregnant women in Sari.

A systematic review and meta-analysis of the prevalence of hepatitis B virus infection among pregnant women in Nigeria

Background

Nigeria has a high burden of hepatitis B virus (HBV) infection, commonly acquired through vertical transmission. However, there is a lack of an efficient surveillance system for monitoring and understanding the epidemiology of HBV among pregnant women. Building on a previous review on the prevalence of HBV in Nigeria (2000–2013), we conducted a systematic review and meta-analysis of HBV prevalence among pregnant women in Nigeria.

Methods

Four electronic databases PubMed, Embase, Global Health, and Scopus were systematically searched from January 2014 to February 2021. We also searched the African Journal Online and manually scanned the reference lists of the identified studies for potentially eligible articles. Observational studies that reported the prevalence of HBsAg and/or HBeAg among pregnant women in peer-reviewed journals were included in the study. We performed a meta-analysis using a random-effects model. We defined HBV infection as a positive test to HBsAg.

Results

From the 158 studies identified, 20 studies with a total sample size of 26, 548 were included in the meta-analysis. The pooled prevalence of HBV infection among pregnant women across the studies was 6.49% (95% confidence interval [CI] = 4.75–8.46%; I² = 96.7%, p = 0.001; n = 20). The prevalence of HBV was significantly lower among pregnant women with at least secondary education compared with those with no education or primary education (prevalence ratio = 0.7, 95% CI = 0.58–0.87; n = 10). However, the prevalence of HBV was not significantly different by age, religion, marital status, or tribe. The prevalence of HBV was not significantly different among pregnant women with previous surgery, blood transfusion, multiple lifetime sex partners, tribal marks, tattoos, scarification, or sexually transmitted infections, compared with those without these risk factors. From a total sample size of 128 (n = 7), the pooled prevalence of HBeAg among HBV-infected pregnant women was 14.59% (95% CI = 4.58–27.99%; I² = 65.5%, p = 0.01). Subgroup analyses of HBV infection by study region and screening method, and meta-regression analysis of the study year, sample size, and quality rating were not statistically significant.

Conclusions

There is an intermediate endemicity of HBV infection among pregnant women in Nigeria. Interventions, such as routine antenatal HBV screening, antiviral prophylaxis for eligible pregnant women, and infant HBV vaccination should be scaled up for the prevention of perinatal transmission of HBV infection in Nigeria.

Hepatitis C Virus in Pregnancy: A Systematic Review of the Literature

OBJECTIVE

The aim of this study was to systematically review the literature to summarize recent demographic characteristics of hepatitis C virus (HCV) infection during pregnancy and the efficacy of risk-based versus universal screening.

STUDY DESIGN

PubMed, EMBASE, and Cochrane Library were searched to identify relevant studies. Studies that recognized hepatitis C as a primary or secondary outcome, with pregnant women as the population and written in English, were included. Studies were excluded if they were abstracts only, written in foreign language, or published prior to 1992. Two researchers independently screened all the studies by titles, abstracts, and full text. Conflicts were settled by a third researcher.

RESULTS

A total of 698 studies were identified with 78 fitting inclusion criteria. In total, 69 epidemiologic and 9 comparison studies were found. Identified risk factors for HCV infection include intravenous or illicit drug use, sexually transmitted coinfection, high-risk behaviors in the partners, high parity, and history of miscarriages or abortions. Demographic characteristics associated with HCV include non-Hispanic white race, American Indian or Alaskan Native ethnicity, and increasing age. Providers may fail to adequately screen for each risk factor, and up to two-thirds of women with a known risk factor are not screened under current guidelines. Finally, up to 27% of HCV+ women have no identifiable risk factors for infection.

CONCLUSION

There is evidence that risk-based screening fails to identify a large proportion of HCV positive women in pregnancy and that pregnant women with HCV risk factors and consistent with current screening guidelines fail to be tested. We urge for the adoption of universal screening to identify these women and offer treatment.

Awareness and prevalence of hepatitis C virus infection among pregnant women in Nigeria: A national pilot cross-sectional study

BACKGROUND

There are no national data on hepatitis C virus awareness and burden among pregnant women to justify its routine screening.

OBJECTIVES

To investigate awareness, seroprevalence and risk factors for hepatitis C virus infection among pregnant women in Nigeria.

METHODS

A total of 159 pregnant women from antenatal clinics across six geopolitical zones in Nigeria consented to anti-hepatitis C virus testing which was confirmed using polymerase chain reaction technique. Confirmed hepatitis C virus positive women were further tested for hepatitis B and HIV. Participants were evaluated for risk factors for hepatitis C virus. Odds ratios, adjusted odds ratios, and their 95% confidence intervals (CIs) were determined, and p-values of <0.05 were considered significant.

RESULTS

Of 159 participants, 77 (48.4%; 95% confidence interval = 38.2%-60.5%) were aware of hepatitis C virus infection and awareness of hepatitis C virus was associated with young age (odds ratio = 2.21; 95% confidence interval = 1.16-4.21), high educational level (odds ratio = 3.29; 95% confidence interval = 1.63-6.64), and participants' occupation (odds ratio = 0.51; 95% confidence interval = 0.26-0.99). In multivariable logistic regression, adjusted for confounders, the association between awareness of hepatitis C virus and participants' young age (adjusted odds ratio = 1.60; 95% confidence interval = 1.09-2.35; p = 0.018) and high educational level (adjusted odds ratio = 1.48; 95% confidence interval = 1.17-1.86; p = 0.001) remained significant. Hepatitis C virus seroprevalence was found to be 1.3% (95% confidence interval = 0.2%-4.5%). All (100.0%, 95% confidence interval = 12.1%-100.0%) the hepatitis C virus-positive participants and 99 (63.1%, 95% confidence interval = 51.3%-76.8%) hepatitis C virus-negative participants had identifiable hepatitis C virus risk factors. Dual seropositivity of anti-hepatitis C virus/anti-HIV and anti-hepatitis C virus/hepatitis B surface antigen each accounted for 0.6%. The most identified risk factors were multiple sexual partners (15.7%), shared needles (13.8%), and blood transfusion (11.3%). There was no significant association between the risk factors and hepatitis C virus positive status.

CONCLUSION

Awareness of hepatitis C virus infection among pregnant women in Nigeria is low and those aware are positively influenced by young age and high educational level. The prevalence of hepatitis C virus infection is high and provides preliminary evidence to justify antenatal routine screening.

Sero-epidemiology of human T-cell lymphotropic viruses-1 and -2 infection among pregnant women attending Abuja Teaching Hospital, Nigeria

BACKGROUND

There is the paucity of HTLV-1/-2 studies on Nigerian pregnant women despite the medical and public health significance of maternal-to-child transmission of HTLV-1/-2.

OBJECTIVE

This study aims to determine the seroprevalence and risk factors of HTLV-1/-2 infections among pregnant women attending the University of Abuja Teaching Hospital (UATH), Abuja, Nigeria.

MATERIALS AND METHODS

Blood samples were collected from consented pregnant women and analysed for ant-HTLV-1/-2 total antibodies using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Pretested structured questionnaires were used to collate participants' socio-demographic variables and risk factors of HTLV infection.

RESULTS

Out of the 156 pregnant women tested for HTLV-1/-2 antibodies, 16 (10.3%) were seropositive. There was no significant association between the socio-demographic variables collated and seroprevalence of HTLV-1/-2 infection among pregnant women (p> 0.05). Pregnant women with HIV infection had a lower prevalence of HLTV-1/-2 infection than those without HIV infections (7.5% versus 11.7%). Pregnant women with multiple sexual partners had a higher risk of HTLV-1/-2 infection than those who had single (OR = 2.08, 95% CI: 0.53-8.18). Women with a history of needles injury had a higher risk of HTLV-1/-2 infection than those who do not (OR = 1.24, 95% CI: 0.38-4.08). The history of blood transfusion was significantly associated with HTLV-1/-2 infection (p= 0.027). However, no significant association existed between other risk factors of HTLV-1/-2 infection among pregnant women (p> 0.05).

CONCLUSION

Considering the 3% pooled national prevalence of HTLV-1/-2 infection in Nigeria, the seroprevalence reported in this study is relatively high. Thus, there is a need for more large cohort studies and routine screening of population at increased risk of infection.

HIV, hepatitis B virus, hepatitis C virus, and syphilis among pregnant women attending antenatal care in Luanda, Angola: Seroprevalence and risk factors

Infectious diseases during pregnancy remain a public health concern, especially in a resource-limited setting. The study aimed to determine the seroprevalence and determinants of HIV and co-infection with hepatitis B virus (HBV), hepatitis C virus (HCV), and syphilis among pregnant women attending antenatal care in Luanda, the capital city of Angola. A cross-sectional study was conducted with 1612 pregnant women screened for HIV during antenatal care. HIV-reactive were also screened for the HBV, HCV, and syphilis using immunoassay kits. A logistic regression model, adjusted odds ratios (AOR) and their 95% confidence interval (CI) were calculated with a level of significance set at 5%. The overall seroprevalence of HIV was 2.6%. About 13% of HIV-positive pregnant women were coinfected. From which, 7.5% were reactive to HBV and 5% to syphilis. There was no reactivity to HCV. Pregnant women younger aged than 25 years were significantly protected from HIV-infection (AOR, 0.43 [95% CI, 0.20-0.91], P = .026). The co-infection was 1.3 times (AOR, 0.04-41.0) in younger aged than 25 years, 7.0 times (AOR, 0.50-99.2) to residents in urbanized areas, and 1.4 times (AOR, 0.10-20.9) in pregnant women with a high educational level. In conclusion, infectious diseases are a public health burden among pregnant women in Luanda. However, include an integrated antenatal screening mainly in urbanized areas is crucial to reduce the spread of infectious diseases in different communities of Angola.

Prevalence, seroconversion and mother-to-child transmission of dual and triplex infections of HIV, hepatitis B and C viruses among pregnant women in Nigeria: study protocol

Background

Nigeria contributes significantly to the global burden of HIV, Hepatitis B and C infections, either singly or in combinations, despite progress in HIV care regionally and globally. Although some limited data on mono infection of HIV, Hepatitis B and C virus infections do exists, that of dual and triplex infections, including seroconversion and mother-to-child transmission (MTCT) rates necessary for planning to address the scourge of infections in pregnancy are not available.

Objectives

To determine the seroprevalence, rate of new infections, MTCT of dual and triple infections of HIV, Hepatitis B and C viruses and associated factors, among pregnant women in Nigeria.

Method

A multicenter prospective cohort study will be conducted in six tertiary health facilities randomly selected from the six geopolitical zones of Nigeria. All eligible pregnant women are to be tested at enrollment after informed consent for HIV, Hepatitis B and C virus infections. While those positive for at least two of the infections in any combination will be enrolled into the study and followed up to 6 weeks post-delivery, those negative for the three infections or positive for only one of the infections at enrolment will be retested at delivery using a rapid diagnostic test. On enrolment into the study relevant information, will be obtained, and laboratory test of CD4 count, liver function test and full blood counts, and prenatal ultrasonography will also be obtained/performed. Management of mother-newborns pairs will be according to appropriate national guidelines. All exposed newborns will be tested for HIV, HBV or HCV infection at birth and 6 weeks using PCR technique. The study data will be documented on the study case record forms. Data will be managed with SPSS for windows version 23. Ethical approval was obtained from National Health Research Ethics Committee (NHREC) (NHREC/01/01/2007–23/01/2020).

Conclusion

Pregnant women with multiple of HIV, HBV and HCV infections are at increased risk of hepatotoxicity, maternal and perinatal morbidity and mortality. Additionally, infected pregnant women transmit the virus to their unborn baby even when asymptomatic. Children born with any of the infection have significantly poorer quality of life and lower five-year survival rate. Unfortunately, the seroconversion and MTCT rates of dual or triplex infections among pregnant women in Nigeria have not been studied making planning for prevention and subsequent elimination of the viruses difficult. The study is expected to fill this knowledge gaps. Nigeria joining the rest of the world to eliminate the triple infection among children rest on the availability of adequate and reliable data generated from appropriately designed, and powered study using representative population sample. The establishment of the three-in-one study of prevalence, rate of new infection, rate and risk factor for MTCT of dual and triple infection of HIV, Hepatitis B and C viruses among pregnant women in Nigeria is urgently needed for policy development and planning for the improvement of the quality of life of mothers and the elimination of childhood triplex infection.

Prevalence of human T-cell lymphotropic virus and the socio-demographic and risk factors associated with the infection among post-natal clinics women in Zaria, Nigeria

Introduction: Human T-cell lymphotropic virus has long been associated with Adult T-cell leukemia/lymphoma, HTLV-associated myelopathy/tropical spastic paraparesis, and hairy cell leukemia. Aim: The aim was to determine the prevalence of HTLV antibodies as well as the socio-demographic and risk factors associated with HTLV among women attending postnatal clinics in Zaria. Methodology: A total of 190 samples were collected within the months of January and June 2017 and qualitative determination of antibodies for HTLV in serum was performed by an antigen sandwich enzyme immunoassay method. Results: The study established an HTLV infection prevalence of 3.2% (6/190). Higher prevalence was observed among women from polygamous families [6.2% (4/64)], the self-employed [6.5% (4/62)], those in age group of 15-25 years [6.2% (5/72)] and women with only primary education [5.9% (2/32)] although the associations were not statistically significant. Similarly, there was no significant association between HTLV infection and history of family cancer (P = .629), intravenous drug use (P = .682), sharing of sharp objects (P = .596,) and history of X-ray exposure (P = .366), except for history of previous blood transfusion which shows significant association (P = .010). Conclusion: The study established a prevalence an HTLV of 3.2% that HTLV in Zaria therefore routinely screened is necessary.

Seroprevalence of HBV, HCV, and HIV and Associated Risk Factors Among Apparently Healthy Pregnant Women in Anyigba, Nigeria

Globally, infection of pregnant women by human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) pose a significant health challenge for not just the mothers but also the newborn infant. This study was undertaken to assess the prevalence of HIV, HCV, and HBV among pregnant women attending antenatal clinic in Kogi State University Teaching Hospital (KSUTH), Anyigba, Nigeria. Sera samples obtained from 200 consented pregnant women were screened for hepatitis B surface antigen (HBsAg), anti-HCV, and anti-HIV antibodies using commercially available immunoassay test kit. Demographic variables and obstetric characteristic were obtained using structured questionnaire. Of the 200 sera tested, the seroprevalence rates were 1.0%, 0.5%, and 8.5% for HBsAg, anti-HCV, and anti-HIV antibodies, respectively. Although 0.5% were coinfected with HIV/HCV, none was simultaneously infected by the three viruses. Age, marital status, trimester, and educational and occupational status did not significantly affect the prevalence of HIV, HCV, and HBV infections. However, factors such as history of abortion/miscarriage (p = 0.04), intravenous drug use (p = 0.001), and history of other sexually transmitted infection (p = 0.01) were significantly higher in relation to HIV seropositivity. In conclusion, findings from this study revealed high HIV seroprevalence and a clear decline of hepatitis C and B infection prevalence compared with previous epidemiological data. Reason for the latter could be attributed to the current efforts to reduce mother-to-child transmission and possible HBV vaccination programs. High burden of HIV infection in our study suggests the needs to strengthen the national prevention programs including education of the people on the risk factors of HIV transmission.

Re-emergence of human T-lymphotropic viruses in West Africa

Human T-lymphotropic viruses (HTLV) are Deltaretroviruses that infect millions of individuals worldwide via the same transmission routes as HIV. With the aim of exposing the possible re-emergence of HTLV in West Africa since discovery, a systematic review was carried out, focusing on the distribution of the virus types and significance of frequent indeterminate reports, while highlighting the need for mandatory routine blood screening. Capturing relevant data from discovery till date, sources searched were Google Scholar, CrossRef, NCBI (PubMed), MEDLINE, Research Gate, Mendeley, abstracts of Conferences and Proceedings, organization websites and reference lists of selected papers. A total of 2626 references were initially retrieved using search terms: Worldwide prevalence of HTLV, HTLV in Africa, HTLV in West Africa, HTLV subtypes, HTLV 3 and 4 in Africa, HTLV of African origin, HTLV seroindeterminate results, Spread of HTLV. These references were rigorously trimmed down to 76. Although evidence shows that HTLV is still endemic in the region, West Africa lacks recent epidemiological prevalence data. Thorough investigations are needed to ascertain the true cause of indeterminate Western Blot results. It is imperative that routine screening for HTLVs be mandated in West African health care facilities.

HTLV-1, the Other Pathogenic Yet Neglected Human Retrovirus: From Transmission to Therapeutic Treatment

Going back to their discovery in the early 1980s, both the Human T-cell Leukemia virus type-1 (HTLV-1) and the Human Immunodeficiency Virus type-1 (HIV-1) greatly fascinated the virology scene, not only because they were the first human retroviruses discovered, but also because they were associated with fatal diseases in the human population. In almost four decades of scientific research, both viruses have had different fates, HTLV-1 being often upstaged by HIV-1. However, although being very close in terms of genome organization, cellular tropism, and viral replication, HIV-1 and HTLV-1 are not completely commutable in terms of treatment, especially because of the opposite fate of the cells they infect: death versus immortalization, respectively. Nowadays, the antiretroviral therapies developed to treat HIV-1 infected individuals and to limit HIV-1 spread among the human population have a poor or no effect on HTLV-1 infected individuals, and thus, do not prevent the development of HTLV-1-associated diseases, which still lack highly efficient treatments. The present review mainly focuses on the course of HTLV-1 infection, from the initial infection of the host to diseases development and associated treatments, but also investigates HIV-1/HTLV-1 co-infection events and their impact on diseases development.

The status of hepatitis B control in the African region

The World Health Organization (WHO) African Region has approximately 100 million people with chronic hepatitis B virus (HBV) infection. This review describes the status of hepatitis B control in the Region. We present hepatitis B vaccine (HepB) coverage data and from available data in the published literature, the impact of HepB vaccination on hepatitis B surface antigen (HBsAg) prevalence, a marker of chronic infection, among children, HBsAg prevalence in pregnant women, and risk of perinatal transmission. Lastly, we describe challenges with HepB birth dose (HepB-BD) introduction reported in the Region, and propose strategies to increase coverage. In 2015, regional three dose HepB coverage was 76%, and 16(34%) of 47 countries reported ≥ 90% coverage. Overall, 11 countries introduced HepB-BD; only nine provide universal HepB-BD, and of these, five reported ≥ 80% coverage. From non-nationally representative serosurveys among children, HBsAg prevalence was lower among children born after HepB introduction compared to those born before HepB introduction. However, some studies still found HBsAg prevalence to be above 2%. From limited surveys among pregnant women, the median HBsAg prevalence varied by country, ranging from 1.9% (Madagascar) to 16.1% (Niger); hepatitis B e antigen (HBeAg) prevalence among HBsAg-positive women ranged from 3.3% (Zimbabwe) to 28.5% (Nigeria). Studies in three countries indicated that the risk of perinatal HBV transmission was associated with HBeAg expression or high HBV DNA viral load. Major challenges for timely HepB-BD administration were poor knowledge of or lack of national HepB-BD vaccination guidelines, high prevalence of home births, and unreliable vaccine supply. Overall, substantial progress has been made in the region. However, countries need to improve HepB3 coverage and some countries might need to consider introducing the HepB-BD to help achieve the regional hepatitis B control goal of < 2% HBsAg prevalence among children < 5 years old by 2020. To facilitate HepB-BD introduction and improve timely coverage, strategies are needed to reach both facility-based and home births. Strong political commitment, clear policy recommendations and staff training on HepB-BD administration are also required. Furthermore, high quality nationally representative serosurveys among children are needed to inform decision makers about progress towards the regional control goal.