Hepatitis B virus: Prevalence, vaccination coverage and immune responses to immunization among healthcare workers at Muhimbili National Hospital

BACKGROUND

Healthcare workers (HCWs) are at an increased risk of contracting and transmitting the hepatitis B virus (HBV). Vaccination coverage against HBV a cost- effective prevention, remains low among HCWs in some settings.

OBJECTIVE

To determine the prevalence of HBV infection, vaccination coverage, and immune responses to HBV vaccine among HCWs at Muhimbili National Hospital (MNH) in Dar es Salaam.

METHODOLOGY

This cross-sectional study used a proportional probability systematic sampling to recruit HCWs from MNH in Dar es Salaam. A structured questionnaire was used to collect social demographic characteristics, infection prevention and control practices, HBV vaccination status and reasons for not vaccinating. Five mLs of a peripheral venous sample was obtained from each participant, the sample was used to test for HBV surface antigen, HBV surface antibody and HBV core antibody for assessing for infection, and vaccine immunity respectively. A Robust Poisson Regression analysis was used to assess factors associated with not vaccinating.

RESULTS

The prevalence of HBV infection was 5 (1.2%) among the 415 recruited HCWs. Only 192 (46.3%) HCWs were vaccinated and 169 (96%) had protective immunity against HBV infection among 176 participants who had received at least two vaccine doses. HCWs who were laboratory scientist aPR = 2.01, 95% CI (1.35-3.00) and had < 10 years of employment aPR = 1.62, 95% CI (1.04-2.50) were unlikely to vaccinate against HBV. Vaccine unavailability 114 (51.1%), hesitancy 42 (18.8%), time constraints 41 (18.4%) and financial constraints 26 (11.7%) were factors associated with not vaccinating.

CONCLUSION

Vaccine coverage against HBV among HCWs at MNH is alarmingly low. Vaccine access, subsidizing cost, protecting time for vaccination could improve vaccination uptake. Qualitative studies are needed to assess for reasons for vaccine hesitancy among HCWs.

Strengthening advanced therapy for sickle cell disease in Africa: experience from sickle cell disease centre in Dar es Salaam, Tanzania

Despite progress in healthcare services for individuals living with sickle cell disease (SCD) in Africa, substantial gaps remain in advanced treatments for SCD. To help address this burden, Tanzania has established one of the largest single-centre SCD programmes in the world and developed an advanced therapy programme for SCD focused on patient engagement and advocacy, clinical activities involving exchange blood transfusion (ExBT) and haematopoietic stem cell transplant (HSCT), gene therapy (GT) preparedness, and enabling partnerships. This report describes the programme's genesis, structure and progress achieved. Patient engagement camps and patient-focused workshops conducted since early 2021 have involved more than 150 patients, family caregivers and healthcare providers. A patient registry was established by screening 1500 patients eligible for advanced therapies with 157 identified to benefit from advanced treatments for SCD. Out of which 22 patients received ExBT, and human leucocyte antigen typing was conducted on 127 individuals to establish a registry of family members with potential to be HSCT donors. Target product profiles were devised for minimum and optimum criteria of GT products to guide drug discovery and development efforts, and qualitative research was conducted to investigate factors anticipated to influence successful adoption of GTs for SCD in Africa. The programme's multifaceted components have been enabled by institutional networks and collaborations established at national, regional and global levels. The programme presented opportunities to deliver cost-effective advanced treatment and curative options for SCD in Tanzania and lessons learnt may be applicable to inform similar efforts in other African regions where SCD is highly endemic.

Strengthening global partnerships for sustainable sickle cell disease care: insights from SickleInAfrica at the 77th United Nations General Assembly and the US-Africa Leaders' Summit

BACKGROUND

Addressing sickle cell disease (SCD) is crucial for achieving health-related Sustainable Development Goals, particularly in Africa. The region is significantly affected, with 78.7% of patients with SCD residing in sub-Saharan Africa and over 515 000 newborns diagnosed annually. Historically, African health systems have struggled to provide optimal care for patients with SCD, resulting in high under-5 mortality and severe childhood morbidity. Scientific innovations and stakeholder engagement offer hope for improving SCD outcomes.

OBJECTIVE

To explore the role of high-level partnerships and scientific innovation in advancing SCD care and research in Africa, focusing on the contributions and strategic engagements of the SickleInAfrica, as highlighted at the 77th United Nations General Assembly (UNGA) and the US-Africa Leaders' Summit.

APPROACH

SickleInAfrica, comprising eight countries, leverages a robust infrastructure for SCD research and care. The consortium has established a comprehensive SCD database and a patient registry in each of the consortium sites that includes demographic details, clinical diagnosis, management details and follow-ups/visits. Currently, over 34 000 patients with SCD are enrolled, making it the largest globally. It has also contextually adapted clinical guidelines for managing SCD for all levels of care. The high-level engagements at the 77th UNGA held in September 2022 in New York and the US-Africa Leaders' Summit held in December 2022 in Washington DC promoted SCD awareness and partnerships. The UNGA session emphasised biomedical science, implementation research and partnerships in therapeutic development, while the US-Africa Leaders' Summit session focused on Global Partnerships for SCD: Advancing Science and Technology for Health in Africa.

CONCLUSIONS

High-level engagements facilitate cross-border dialogues, underscoring the importance of partnerships from grassroots to global alliances. Key outcomes include increased awareness, policy advocacy and the establishment of SCD Centres of Excellence and genomics capacity-building initiatives. Sustainable efforts require robust partnerships, government involvement, community awareness and equitable access to advanced therapies.

Low vitamin B12 blood levels in sickle cell disease: Data from a large cohort study in Tanzania

Sickle cell disease (SCD) is associated with high rates of undernutrition and stunting. Undernutrition in combination with chronic haemolysis may lead to deficiencies in micronutrients necessary for erythropoiesis. Here we examined selected levels of ferritin, vitamins B2 , B6 , B9 and B12 , and vitamin C that were measured in blood samples from 820 SCD patients from Tanzania with no history of hospital admission, infections or painful episodes in the previous 30 days. We studied children (0-8 years), early adolescents (9-14 years), late adolescents (15-17 years) and adults (≥18 years). Severely low levels of vitamin B12 were observed across the four age groups. Despite the lowered vitamin B12 concentrations, total homocysteine concentrations were normal across both genders in all age groups. We found no significant gender-related differences between the other measured micronutrients. In this large SCD population, spanning the whole life cycle, a low level of vitamin B12 was consistently found across both genders and all age groups. Given the pivotal role of vitamin B12 in cellular metabolism, particularly in erythropoiesis, more studies are required to unravel how to better detect clinically relevant vitamin B12 deficiency among SCD patients, and thus to identify more precisely those who need supplementation of vitamin B12 .