COVID-19 and mental health services in Sub-Saharan Africa: A critical literature review.

BACKGROUND: The COVID-19 pandemic has wrought a profound impact on mental health in Sub- Saharan Africa, exacerbating existing disparities and rendering individuals undergoing treatment particularly susceptible. This comprehensive critical review delves into the scope, nature, and extent of COVID-19 impact on mental health services in Sub- Saharan Africa, while concurrently elucidating pivotal lessons and exemplary practices learnt from periods of lockdown. METHODS: The methodology was guided by Jesson & Laccy's guide on how to conduct critical literature reviews. Articles were comprehensively sought through two academic databases (PubMed and Google Scholar), complemented by targeted searches on the WHO website and official public health websites of relevant Sub-Saharan African countries. RESULTS: The investigation reveals a surge in mental health challenges, notably marked by a significant escalation in anxiety, depression, and post-traumatic stress disorder. Disruptions to care services, financial hardships, and the pervasive effects of social isolation further compound this escalation. The pre-existing inequalities in access to and quality of care were accentuated during this crisis, with marginalized groups encountering heightened impediments to essential services. In navigating this unprecedented challenge, communities emerged as integral agents in establishing supportive networks and implementing culturally sensitive interventions. Technology, such as telemedicine and online resources, played a pivotal role in bridging access gaps, particularly in remote areas. The synthesis of best practices for supporting mental health patients during lockdowns encompasses targeted interventions for vulnerable groups, including adolescents and pregnant women. Empowering communities through economic support and mental health literacy programs was identified as crucial. The integration of technology, such as the development of robust telemedicine frameworks, virtual training in curricula, and the utilization of digital platforms for interventions and public messaging, emerged as a cornerstone in addressing access disparities. Community engagement and resilience-building strategies gained prominence, emphasizing the necessity of collaboration between healthcare providers and communities. Promotion of peer support groups, home-based care, and the preservation of traditional healing practices were underscored as essential components. CONCLUSION: The study underscores the need to adapt and optimize mental health services during emergencies. This entails prioritizing mental health within emergency response frameworks, exploring alternative service delivery methods, and fortifying data collection and research efforts.

Postpartum Women's Experiences of Postnatal Care in Sub-Saharan Africa: A Qualitative Evidence Synthesis.

BACKGROUND: Postnatal care (PNC) is a critical service for the health and well-being of new mothers and newborns. However, in sub-Saharan Africa (SSA), most efforts to improve maternal and child health have been directed toward enhancing skilled birth attendance and urgent obstetric and neonatal care. This is despite the fact that more than half of maternal deaths globally occur in the postnatal period, with 65% of these occurring in the first week following birth. One of the health system factors influencing PNC utilization is the women's previous PNC experience at healthcare facilities. The aim of this review was to gain a better understanding of women's experiences of PNC in SSA. METHODS: This study followed a qualitative evidence synthesis design. The phenomenon of interest was postpartum women's experiences of PNC in SSA. PubMed, CINAHL, EMBASE, Science Direct, Africa Journals Online (AJOL), SCOPUS, and Google Scholar were searched for peer-reviewed articles published in English between 2013 and 2023. To assess the quality of the included studies, we used an appraisal tool developed by the Evidence for Policy and Practice Information and Co-ordinating Centre. Two authors independently extracted relevant data from the included studies. Thomas and Harden's thematic synthesis framework was used to synthesize the data. RESULTS: Eight articles were used in this review. Seven articles reported on qualitative studies, and one reported on a mixed-method study. All the included studies fully or partially met the 12 quality assessment criteria. Synthesis of the data resulted in the development of five analytical themes. The five themes were the adequacy of physical examination and communication of the findings, adequacy of PNC information, the quality of interactions with healthcare workers (HCWs), the availability of resources and adequacy of HCWs, and denial of care. The overall confidence in the review's findings was either moderate or high. CONCLUSION: Based on our findings, we recommend that countries in the region address staff shortages, implement task shifting, electronic medicine stock management systems, optimal supply chain policies, and train HCWs on PNC and interpersonal communication skills.

Implementation of Public Health Genomics in Africa: Lessons from the COVID-19 pandemic, challenges, and recommendations.

Public Health Genomics (PHG) is a relatively new field. The wide application of genomic technologies played a pivotal role in elucidating the full genomic sequence of the SARS-CoV-2 virus. This breakthrough proved to be the starting point in the manufacture of diagnostic kits and the subsequent making of vaccines. Beyond the COVID-19 pandemic, many African countries can take advantage of the various investments in genomic technologies to introduce and intensify the use of genomics for public health gain. Public Health Genomics effectively monitors, prevents, and manages non-communicable and infectious diseases. However, there are several challenges to implementing PHG in Africa. In this perspective article, we discuss the utilization of PHG during the COVID-19 pandemic, the lessons learned from using PHG to manage and contain the COVID-19 pandemic, as well as potential challenges Africa may face when putting PHG into practice compared to challenges of other regions. We also discuss our recommendations for overcoming these challenges.

Cervical cancer in sub-Saharan Africa: an urgent call for improving accessibility and use of preventive services.

Sub-Saharan Africa has the highest rates of cervical cancer in the world, largely attributed to low cervical cancer screening coverage. Cervical cancer is the most common cause of death among women in 21 of the 48 countries in sub-Saharan Africa. Close to 100% of all cases of cervical cancer are attributable to Human papillomavirus (HPV). HPV types 16 and 18 cause at least 70% of all cervical cancers globally, while types 31, 33, 45, 52, and 58 cause a further 20% of the cases. Women living with HIV are six times more likely to develop cervical cancer than those without HIV. Considering that sub-Saharan Africa carries the greatest burden of cervical cancer, ways to increase accessibility and use of preventive services are urgently required. With this review, we discuss the preventive measures required to reduce the burden of cervical cancer in sub-Saharan Africa, the challenges to improving accessibility and use of the preventive services, and the recommendations to address these challenges.

Accessibility and utilization of antenatal care services in sub-Saharan Africa during the COVID-19 pandemic: A rapid review.

Control measures for the COVID-19 pandemic brought unprecedented challenges to health care delivery. Some countries in sub-Saharan Africa (SSA) stopped the provision of essential health care except for those services that were deemed emergencies or life-threatening. A rapid review was conducted on March 18, 2022, on the accessibility and utilization of antenatal care services in sub-Saharan Africa during the COVID-19 pandemic. PubMed, Google Scholar, SCOPUS, and the World Health Organization library databases were searched for relevant studies. A modified Population, Intervention, Control, and Outcomes (PICO) framework informed the development of the search strategy. The review included studies conducted within Africa that described the availability, access, and utilization of antenatal services during the COVID-19 pandemic. Eighteen studies met the inclusion criteria. This review revealed a reduction in access to ANC services, an increase in the number of home deliveries, and a reduction in the number of women attending ANC visits during the COVID-19 pandemic. A decrease in ANC service utilization was reported in some studies in the review. Barriers to ANC access and utilization during the COVID-19 pandemic included movement restrictions, limited transport access, fear of contracting COVID-19 at the health facilities, and facility barriers. The use of telemedicine needs to be improved in African countries to allow for the continued provision of health services during pandemics. In addition, there should strengthening of community involvement in the provision of maternal health services post-COVID-19 so that services may be able to better withstand future public health emergencies.

Making every baby count - An urgent reproductive health priority as sub-Saharan Africa continues to witness a high incidence of stillbirths.

The expected culmination of a positive pregnancy experience is a healthy mother and a bouncing live baby. Unfortunately, globally an estimated 2 million babies are still born every year, with the largest incidence of stillbirths of about 50% of the global burden occurring in sub-Saharan Africa (SSA). Significant gaps in access to quality antenatal care (ANC) and labour and delivery remain in SSA. It is estimated that only 24% of women receive at least four ANC visits in SSA. Women are prepared for labour and delivery during this period, and risk factors are identified, and potential complications can be averted. Access to labour and delivery services is critical for picking up foetal compromise. Women must deliver in facilities that can offer assisted delivery and offer foetal and neonatal resuscitation, to prevent stillbirths and early neonatal deaths. In SSA, many primary healthcare facilities are unable to offer these services, whilst higher level facilities that can offer these may be difficult to access. The majority of stillbirths are preventable if women access quality ANC and can access modern facilities for labour and delivery. Therefore, stakeholders in reproductive health must ensure access to ANC for a positive pregnancy experience.

Le point culminant attendu d'une expérience de grossesse positive est une mère en bonne santé et un bébé vivant et rebondissant. Malheureusement, on estime que 2 millions de bébés naissent encore chaque année dans le monde, la plus grande incidence de mortinatalité, représentant environ 50 % du fardeau mondial, se produisant en Afrique subsaharienne (ASS). Des lacunes importantes subsistent en matière d'accès à des soins prénatals (CPN) de qualité, au travail et à l'accouchement en ASS. On estime que seulement 24 % des femmes reçoivent au moins quatre visites prénatales en ASS. Les femmes sont préparées au travail et à l'accouchement pendant cette période, les facteurs de risque sont identifiés et les complications potentielles peuvent être évitées. L'accès aux services de travail et d'accouchement est essentiel pour détecter une atteinte foetale. Les femmes doivent accoucher dans des établissements capables de proposer un accouchement assisté et de proposer une réanimation foetale et néonatale, afin de prévenir les mortinaissances et les décès néonatals précoces. En ASS, de nombreux établissements de soins de santé primaires ne sont pas en mesure d'offrir ces services, tandis que les établissements de niveau supérieur qui peuvent les offrir peuvent être difficiles d'accès. La majorité des mortinaissances sont évitables si les femmes accèdent à des soins prénatals de qualité et peuvent accéder à des installations modernes pour le travail et l'accouchement. Par conséquent, les acteurs de la santé reproductive doivent garantir l'accès aux soins prénatals pour une expérience de grossesse positive.

Expanding technical assistance: a call for a more nuanced approach for sustainable HIV programs in Sub-Saharan Africa.

An anticipated decline in external funding in sub-Saharan Africa (SSA) necessitates a re-evaluation of HIV response sustainability strategies. While institutional capacity building (ICB) has yielded positive outcomes, including strengthened technical expertise and institutional frameworks, it faces challenges. These include overemphasis on technical expertise neglecting resource mobilization, and a limited focus on policy advocacy. To achieve long-term sustainability, ICB efforts must equip local institutions with skills for tailored donor engagement, data-driven advocacy, and collaborative policy influence. This multi-pronged approach, coupled with efforts to diversify funding and integrate HIV responses, is crucial to empower local ownership and ensure the long-term viability of effective HIV responses in SSA.

Human papilloma virus vaccination in the resource-limited settings of sub-Saharan Africa: Challenges and recommendations.

Human papillomaviruses (HPV) cause 99% of all cervical cancer cases globally, with the high-risk genotypes 16 and 18 causing at least 70% of these cases. An estimated 90% of the global cervical cancer burden occurs in low-to-middle-income countries (LMICs), particularly in sub-Saharan Africa (SSA). Primary prevention through the administration of efficacious HPV vaccines is key to the World Health Organization's global strategy for accelerating the elimination of cervical cancer as a disease of public health concern. The rollout of HPV vaccination in SSA is faced with several challenges, such as the high cost of vaccine procurement, a lack of funding and political will from the central governments of countries, and inadequate infrastructure for vaccine cold chain storage and transport. Stigma, misinformation, lack of education and awareness, and vaccine hesitancy constitute the social factors that affect the successful rollout or implementation of vaccination programs in SSA. Based on the challenges SSA faces in rolling out HPV vaccination, we recommend using strategies that address both the demand-side and supply-side obstacles to HPV vaccination uptake. These include costs and availability, fighting vaccine hesitancy, and increasing vaccine confidence.

Men's involvement in maternal health in sub-Saharan Africa: A scoping review of enablers and barriers.

BACKGROUND: Globally, there are about 800 maternal deaths every day, with low-to-middle-income countries accounting for most of these deaths. A lack of access to maternal healthcare services is one of the main causes of these deaths. In sub-Saharan Africa (SSA), one of the barriers to accessing maternal healthcare services by women is a lack of their male partners' involvement. This scoping review aimed to assess the enablers and barriers to men's involvement in maternal healthcare services. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) checklist was used as a guide for this review. We searched for peer-reviewed articles published between 2013 and 2023 in the English language from SCOPUS, ScienceDirect, PubMed, Africa Journals Online (AJOL), and Google Scholar databases. Two reviewers independently conducted the data extraction and article selection. All of the authors discussed and decided on the codes and categories for enablers and barriers after using NVivo to generate them. RESULTS: Twenty-seven articles were used in this review. Of these, seventeen were qualitative studies, six were quantitative studies, and four were mixed-methods studies. The enablers of men's involvement in maternal healthcare were grouped into sociodemographic factors, health system factors, and policy factors, while barriers were grouped into sociodemographic, cultural, economic, and health system barriers. The lack of maternal health knowledge, insufficient economic resources, and unfriendly staff at healthcare facilities all contributed to a lack of involvement by men. CONCLUSION: To improve men's involvement in maternal healthcare in SSA, there should be economic empowerment of both men and women, health education, and the provision of adequate infrastructure in healthcare facilities to accommodate men.

Closing the equity gap: A call for policy and programmatic reforms to ensure inclusive and effective HIV prevention, treatment and care for persons with disabilities in Eastern and Southern Africa.

In this paper, we explore the critical barriers that persons with disabilities face in accessing HIV services in the Eastern and Southern Africa (ESA) region, despite significant advancements in overall accessibility. We highlight the intersectional challenges experienced by individuals with disabilities, particularly women, and outline a comprehensive approach to bridge the existing gaps in policy and programmatic efforts. Specifically, we aim to address the exclusion of persons with disabilities from essential HIV prevention, treatment, and care services, a situation that has profound implications for their health, social inclusion, and economic productivity. In this discussion, we examine the current landscape, identify specific policy and programmatic hurdles, and propose targeted reforms, in an effort to contribute to the ongoing discourse on health equity and inclusivity.

A critical review of mpox outbreaks, risk factors, and prevention efforts in Africa: lessons learned and evolving practices.

Objectives: In recent years, mpox, a zoonotic disease caused by the mpox virus, has transcended its primary association with Central and West Africa, emerging as a global public health concern. The virus poses a substantial threat, particularly, to vulnerable demographics such as young children and individuals with compromised immune systems. This critical literature review aimed to comprehensively evaluate the burden, risk factors, and current management strategies associated with mpox in Africa. Methods: This critical literature review was guided by Jesson & Laccy's guidelines on conducting critical literature reviews. We searched PubMed and Google Scholar databases and websites of the World Health Organization and health ministries in different African countries. We included articles written in English and published between 2010 and 2023. The synthesis of findings involved several steps, including summarizing themes, integrating themes, and linking themes to research questions. Results: A total of 25 articles were included in this review. The review revealed that mpox cases are concentrated in Central African countries. The risk factors for mpox identified include being in contact with bushmeat or rodents, not having been vaccinated against smallpox, being HIV-positive, and having close physical contact with someone with the disease. The clinical presentation of mpox revealed in this review includes a skin rash, fever, lymphadenopathy, headache, pruritus, sore throat, and body aches. Four themes arose on strategies to prevent and control mpox in Africa. Conclusions: The prevention and control of mpox in Africa require an improvement in community education, vaccination, disease surveillance, and infection control measures.

The impact of DNA tumor viruses in low-to-middle income countries (LMICS): A literature review.

DNA viruses are common in the human population and act as aetiological agents of cancer on a large scale globally. They include the human papillomaviruses (HPV), Epstein-Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV), hepatitis viruses, and human polyomaviruses. Oncogenic viruses employ different mechanisms to induce cancer. Notably, cancer only develops in a minority of individuals who are infected, usually following protracted years of chronic infection. The human papillomaviruses (HPVs) are associated with the highest number of cancer cases, including cervical cancer and other epithelial malignancies. Hepatitis B virus (HBV) and the RNA virus hepatitis C (HCV) are significant contributors to hepatocellular cancer (HCC). Other oncoviruses include Epstein-Barr virus (EBV), Kaposi sarcoma-associated herpes virus (KSHV), human T-cell leukemia virus (HTLV-I), and Merkel cell polyomavirus (MCPyV). The identification of these infectious agents as aetiological agents for cancer has led to reductions in cancer incidence through preventive interventions such as HBV and HPV vaccination, HPV-DNA based cervical cancer screening, antiviral treatments for chronic HBV and HCV infections, and screening of blood for transfusion for HBV and HCV. Successful efforts to identify additional oncogenic viruses in human cancer may provide further understanding of the aetiology and development of cancer, and novel approaches for prevention and treatment. Cervical cancer, caused by HPV, is the leading gynaecological malignancy in LMICs, with high age-standardised incidence and mortality rates, HCC due to HBV is an important cause of cancer deaths, and the burden of other cancer attributable to infections continues to rise globally. Hence, cancers attributable to DNA viruses have become a significant global health challenge. These viruses hence warrant continued attention and interrogation as efforts to understand them further and device further preventive interventions are critical.

Water, sanitation, and hygiene-specific risk factors of recent diarrheal episodes in children aged under 5 years: analysis of secondary data from the multiple indicator cluster survey (MICS 2019).

Objectives: Access to safe drinking water, sanitation, and hygiene, collectively called WASH, is a fundamental human right and a cornerstone of public health. However, inadequate WASH practices and environments significantly contribute to the global burden of diarrheal diseases, particularly, in children aged under 5 years. Inadequate WASH conditions are the primary drivers of various infectious diseases, including cholera, dysentery, hepatitis A, typhoid, and polio. Methods: We conducted secondary data analysis using the 2019 Zimbabwe Multiple Indicator Cluster Survey to investigate the specific WASH risk factors associated with recent diarrheal episodes in children aged under 5 years. Results: A total of 853 (14%) of 6092 children were reported to have experienced an episode of diarrhea in the last 2 weeks preceding the survey. Having insufficient water in the household was associated with 17.0% diarrhea episodes compared with 13.6% in those who did not face this problem. The availability of soap or detergents to wash hands was associated with a risk of diarrhea, with an odds ratio and 95% confidence interval of 1.19 (1.01-1.40), P = 0.033. The use of surface water, including rivers, dams, lakes, ponds, streams, canals, and irrigation channels, was associated with differences in diarrheal episodes, although this was of borderline significance, P = 0.082. Of the children who had a recent episode of diarrhea, 41.0% had their parents or caregivers seeking medical attention. Conclusions: There is need for an improvement in safe water supply to households and an improvement in health education on the importance of using soap after using the toilet to avoid contamination of food and water.

Empowering underprivileged students beyond financial aid: Insights from a scholarship program's monitoring and evaluation.

PURPOSE: This paper examines the impact of a scholarship program on underprivileged students, drawing on data from a two-year monitoring and evaluation (M&E) process. The report identifies both enablers and barriers to academic success among scholarship beneficiaries. METHODS: Data on program impact was collected through interviews with parents, teachers, and school records over two academic years. RESULTS: Financial aid emerged as a crucial enabler, with scholarships allowing students to focus on their studies by alleviating pressure around basic necessities. However, the research also revealed the importance of a holistic support system. Beyond tuition, the high cost of essential learning materials, including stationery, and subject-specific resources, can create a significant barrier. The study also highlighted the importance of student well-being. Health concerns, limited access to nutritious food, and even unaddressed mental health issues can all negatively impact attendance and focus. Furthermore, a gender gap emerged, with girls facing additional challenges related to social pressures to prioritize chores and the cost of menstrual hygiene products. CONCLUSION: This study highlights the importance of holistic scholarship programs that extend beyond tuition coverage. To maximize impact, policymakers and funders should prioritize initiatives that address the multifaceted needs of underprivileged students.

Predicting sexually transmitted infections among men who have sex with men in Zimbabwe using deep learning and ensemble machine learning models.

There is a substantial increase in sexually transmitted infections (STIs) among men who have sex with men (MSM) globally. Unprotected sexual practices, multiple sex partners, criminalization, stigmatisation, fear of discrimination, substance use, poor access to care, and lack of early STI screening tools are among the contributing factors. Therefore, this study applied multilayer perceptron (MLP), extremely randomized trees (ExtraTrees) and XGBoost machine learning models to predict STIs among MSM using bio-behavioural survey (BBS) data in Zimbabwe. Data were collected from 1538 MSM in Zimbabwe. The dataset was split into training and testing sets using the ratio of 80% and 20%, respectively. The synthetic minority oversampling technique (SMOTE) was applied to address class imbalance. Using a stepwise logistic regression model, the study revealed several predictors of STIs among MSM such as age, cohabitation with sex partners, education status and employment status. The results show that MLP performed better than STI predictive models (XGBoost and ExtraTrees) and achieved accuracy of 87.54%, recall of 97.29%, precision of 89.64%, F1-Score of 93.31% and AUC of 66.78%. XGBoost also achieved an accuracy of 86.51%, recall of 96.51%, precision of 89.25%, F1-Score of 92.74% and AUC of 54.83%. ExtraTrees recorded an accuracy of 85.47%, recall of 95.35%, precision of 89.13%, F1-Score of 92.13% and AUC of 60.21%. These models can be effectively used to identify highly at-risk MSM, for STI surveillance and to further develop STI infection screening tools to improve health outcomes of MSM.

The HIV/AIDS responses pre and during the COVID-19 pandemic in sub-Saharan Africa: A basis for sustainable health system strengthening post-COVID-19.

In May 2023, the World Health Organization announced that COVID-19 was no longer a global emergency. The impact of COVID-19 on the provision of HIV/AIDS services was not that severe due to the reprogramming of key resources. For health systems in sub-Saharan Africa to become resilient to future pandemics, lessons should be learned from the successful HIV/AIDS response in the region, and how the HIV/AIDS services were successfully adapted to the COVID-19 pandemic. In this article, we reviewed the 6 World Health Organization health system building blocks on how the best practices from the provision of HIV/AIDS services and the services' response to the COVID-19 pandemic can be used as a basis for restoring and strengthening health systems to offer universal access to quality essential health services. The success of the leadership and governance for universal access to anti-retroviral therapy can be a blueprint for the realization of universal health coverage. Significant efficiencies that resulted in the reduction in anti-retroviral therapy costs can be leveraged to ensure cheaper essential drugs while differentiated service delivery models can be used to improve health service accessibility. New technologies that have proven to be successful in HIV/AIDS care can also be used in the care of other diseases, including disease outbreaks. The strong health information systems developed for HIV programs can be used as a foundation for developing health information systems for the whole health sector while the healthcare professionals trained for the provision of HIV/AIDS services can be trained to provide services for a variety of other conditions.

Health effects of climate change in Africa: A call for an improved implementation of prevention measures.

The world's climate, particularly in Africa, has changed substantially during the past few decades, contributed by several human activities. Africa is one of the continents that is most vulnerable to climate change globally. Since the beginning of 2022, extreme weather events in Africa have affected about 19 million people and killed at least 4,000 individuals. Cyclones, floods, heatwaves, wildfires, droughts, and famine were among the severe weather occurrences. Natural disasters and extreme weather events brought on by climate change may compromise access to clean water, sanitation systems, and healthcare facilities, making people more vulnerable to a number of illnesses. Floods and drought can lead to both communicable and non-communicable diseases. The African population is more likely to experience more mental health disorders than before because of natural disasters, which result in the loss of property and sometimes loss of lives more frequently. We, therefore, call for an improved implementation of strategies to prevent the health effects of climate change so that the health of the people in Africa can be maintained.

The Use of Economic Evaluation Tools in Essential Health Benefits Package Selection for Universal Health Coverage.

OBJECTIVES: The sustainable development goals launched in 2015 are a follow-up commitment to the successful Millennium Development Goals. Goal number 3 of ensuring "good health and well-being" is a target to ensure universal health coverage. Universal health coverage means the provision of quality services that meet the needs of populations without risking financial impoverishment in the process. The guaranteed minimum health services in every health system constitute the health benefits package (HBP), which should be explicit and be composed of services that represent the best value for money and guarantee the best return on investment. The objective of this study was to review the application of cost-effectiveness analysis (CEA) and budget impact analysis in the development of HBP in low-to-middle income countries across the world. METHODOLOGY: A literature review using a systematic approach was used. A search of PubMed, Google Scholar, World Health Organization, and World Bank databases was made for articles outlining the development of HBP in low- and middle-income countries, and a narrative synthesis was used for analysis. RESULTS: Results from processes in Armenia, Ethiopia, Kyrgyz Republic, Lebanon, and Malawi showed CEA and budget impact analysis as 2 criteria used in HBP development in a limited number of countries with either no reference to the two or no reporting from the others. Local CEA estimates and cost data limitations were the biggest challenges to efforts to use robust methods. CONCLUSION: Sustained efforts are needed to understand and address the challenges to the use of economic evaluation in the development of HBPs.