Influence of schistosomiasis on host vaccine responses Nono, Justin Komguep; Kamdem, Severin Donald; Musaigwa, Fungai ...
Trends in parasitology,
January 2022, 2022-01-00, 20220101, Volume:
38, Issue:
1
Journal Article
Peer reviewed
Schistosomiasis is a debilitating helminthiasis which commonly establishes as a chronic infection in people from endemic areas. As a potent modulator of the host immune response, the Schistosoma ...parasite and its associated products can directly interfere with its host’s ability to mount adequate immune responses to unrelated antigens. As a result, increased attention is gathering on studies assessing the influence of helminths, particularly the causal agent of schistosomiasis, on host responsiveness to vaccines. However, to date, no consensus has been drawn regarding the influence of schistosomiasis on host vaccine responses. Here, we review available evidence on the influence of transgenerational and direct Schistosoma parasite exposure on host immune responses to unrelated vaccines. In addition, we evaluate the potential of praziquantel (PZQ) treatment in restoring schistosomiasis-impacted vaccine responses.
Vaccines are the greatest weapon nowadays against infectious diseases as they have contributed to eradicate or significantly lower their burden.In developing countries, vaccinated persons display lower vaccine responsiveness in comparison to those from the developed world.Direct and transgenerational exposure to Schistosoma spp. may alter the immunological, microbial, metabolic, and physiological wiring of hosts and impact their ability to respond to vaccines; treatment with praziquantel might potentially reverse this effect.Discrepancies in human studies blur our understanding of the real influence of Schistosoma spp. infection on vaccine responses.Furthering our understanding of the influence of Schistosoma spp. infection on human vaccine responses via controlled clinical studies and the use of animal models could inform strategies for vaccination in schistosomiasis-endemic areas.
Missed opportunities for vaccination in Africa Adetokunboh, Olatunji; Iwu-Jaja, Chinwe Juliana; Nnaji, Chukwudi A ...
Current opinion in immunology,
August 2021, 2021-08-00, 20210801, Volume:
71
Journal Article
Peer reviewed
•Missed opportunity for vaccination (MOV) needs to be addressed to improve vaccine coverage.•The associated factors for MOV can be grouped into caregiver, health service delivery/system, and ...healthcare worker factors.•The prevalence of MOV vary across the African continent.
The purpose of this review is to assess the extent of missed opportunities for vaccination (MOV) in Africa, determine the associated factors, and provide recommendations that countries could adopt in reducing MOV. Two databases were searched for multinational studies and systematic reviews reporting MOV and involving African countries. A total of 288 records were identified and 12 studies included for synthesis. The prevalence ranged from 47.0% to 62.1%, with a weighted mean of 27.3%. This review highlighted caregiver utilization, health service delivery, and healthcare worker' factors associated with MOV. Understanding the extent of MOV in Africa presents an opportunity for multiple approaches to resolve the differential factors that contribute to MOV, and to bridge the gap in vaccination coverage in the continent.
Following decades of extensive research and development, a second malaria vaccine, the R21/Matrix-M vaccine, has been recommended by WHO.1 The recommendation comes at a crucial time when progress has ...stalled over the past decade due to a host of factors, including parasite resistance and persisting suboptimal access to preventive interventions, diagnostics, and therapeutics, with service disruptions by the COVID-19 pandemic posing additional constraints.2 The addition of the new vaccine to the arsenal of malaria control and elimination tools offers a glimmer of hope and creates an impetus for expediting current efforts. Anticipated supply of the R21/Matrix-M vaccine from the Serum Institute of India and the recent agreement between UNICEF and Serum Life Sciences to secure additional supplies are both positive steps.4 However, expanding the number of manufacturers further can help to prevent the risks associated with having a limited pool of producers, such as inadequate or interrupted global supply, should there be unanticipated disruptions (as was evident with the COVID-19 pandemic). ...enabling vaccine manufacturing in the African continent could have the added advantage of lowering production costs in the medium to long term and could also boost global supply to reach populations in essential need of protection from the devasting burden of malaria. Reducing costs of vaccine production is particularly crucial, given the dire economic situations in many countries bearing the highest burden of malaria—which could ultimately mean less fiscal space for such countries to mobilise and allocate resources to meet broader vaccine financing and co-financing obligations.
The coronavirus disease 2019 (COVID-19) pandemic has immensely disrupted health care services globally. The pandemic has been particularly disruptive for cancer services and more so in low-resource ...settings. In this narrative review, we highlight the reported impact of the COVID-19 pandemic on cancer prevention, screening, diagnosis, treatment and research across the African continent. We also explore ways in which identified structural and contextual constraints can be navigated for the re-escalation of oncological activities, while discussing how the pandemic has necessitated the reimagination of how oncology services can be delivered now and in the future. We conducted a literature search of MEDLINE (via PubMed) and Scopus for relevant articles and synthesised the findings thematically. In spite of the dearth of data, available evidence suggests a substantial impact of the pandemic on the various aspects of cancer management in African countries. Aggravating factors include pre-existing health system and cancer management gaps in many countries within the region, which are typically faced with inadequate availability of oncology resources, oncologists and other vital resources; in addition to the acute and lingering consequences of social distancing, movement restrictions and other public health measures implemented to contain the spread of the virus. As the pandemic evolves and movement restrictions are eased, there is a need for the timely and safe return to normal oncological care. This will require a risk-adjusted and multidisciplinary approach, with the aim of mitigating the further impact of the disruption on cancer patients, their families and healthcare providers.
This study aimed to explore the contextual factors that may be associated with missed opportunities for vaccination (MOV) from the perspectives of healthcare providers and caregivers attending ...primary healthcare facilities in the Cape Town Metro Health District, South Africa. The ultimate goal of the assessment was to help inform the design and implementation of a contextually appropriate quality improvement programme targeted at reducing MOV in primary healthcare settings. We used a theory-informed exploratory qualitative research design involving focus group discussions with caregivers of children aged 0-23 months; and in-depth interviews of facility staff. A thematic template analysis approach, integrating the theoretical domains framework (TDF) and the capability, opportunity and motivation model of behavior (COM-B) was used to code and analyze the data. Three focus group sessions were conducted, each consisting of 5-8 caregivers and five in-depth interviews involving facility staff. Capability factors comprised caregivers' knowledge, attitude and behavior toward children's immunization. Opportunity factors included the organization of immunization services, long waiting time, vaccine stock out, staff shortage and health workers' attitude, knowledge and capability to assess children's immunization status and needs. Motivation factors included optimism and beliefs about immunization, fear of vaccine-preventable diseases and immunization safety concerns. This study identified important caregiver-, provider- and health system-related factors, which influence immunization outcomes; offering useful contextual insights for informing quality improvement strategies for reducing MOV at primary healthcare level.
Population-based surveys, such as those conducted by the Demographic and Health Surveys (DHS) Programme, can collect and disseminate the data needed to inform cancer control efforts in a standardised ...and comparable manner. This review examines the DHS questionnaires, with the aim of describing and analysing how cancer-specific questions have been asked from the inception of the surveys to date. A systematic search of the DHS database was conducted to identify cancer-specific questions asked in surveys. Descriptive statistics were used to summarise the cancer-specific questions across survey years and countries. In addition, the framing and scope of questions were appraised. A total of 341 DHS surveys (including standard, interim, continuous and special DHS surveys) have been conducted in 90 countries since 1985, 316 of which have been completed. A total of 39 (43.3%) of the countries have conducted at least one DHS survey with one or more cancer-specific questions. Of the 316 surveys with available final reports and questionnaires, 81 (25.6%) included at least one cancer-specific question; 54 (17.1%) included questions specific to cervical cancer, 41 (13.0%) asked questions about breast cancer, and 8 (2.5%) included questions related to prostate cancer. Questions related to other cancers (including colorectal, laryngeal, liver, lung, oral cavity, ovarian and non-site-specific cancers) were included in 40 (12.6%) of the surveys. Cancer screening-related questions were the most commonly asked. The majority of the surveys included questions on alcohol and tobacco use, which are known cancer risk factors. The frequency of cancer-specific questions has increased, though unsteadily, since inception of the DHS. Overall, the framing and scope of the cancer questions varied considerably across countries and survey years. To aid the collection of more useful population-level data to inform cancer-control priorities, it is imperative to improve the scope and content of cancer-specific questions in future DHS surveys.
ObjectivesTo systematically synthesise available evidence on the nature and effectiveness of interventions for improving timely diagnosis of breast and cervical cancers in low and middle-income ...countries (LMICs).DesignA systematic review of published evidence. The review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses.Data sourcesA comprehensive search of published literature was conducted. In addition, relevant grey literature sources and bibliographical references of included studies were searched for potentially eligible evidence.Study selectionStudies published between January 2010 and November 2020 were eligible for inclusion. To be eligible, studies had to report on interventions/strategies targeted at women, the general public or healthcare workers, aimed at improving the timely diagnosis of breast and/or cervical cancers in LMIC settings.Data extraction and synthesisLiterature search, screening, study selection, data extraction and quality appraisal were conducted by two independent reviewers. Evidence was synthesised and reported using a global taxonomy framework for early cancer diagnosis.ResultsFrom the total of 10 593 records identified, 21 studies conducted across 20 LMICs were included in this review. Most of the included studies (16/21) focused primarily on interventions addressing breast cancers; two focused on cervical cancer while the rest examined multiple cancer types. Reported interventions targeted healthcare workers (12); women and adolescent girls (7) and both women and healthcare workers (3). Eight studies reported on interventions addressing access delays; seven focused on interventions addressing diagnostic delays; two reported on interventions targeted at addressing both access and diagnostic delays, and four studies assessed interventions addressing access, diagnostic and treatment delays. While most interventions were demonstrated to be feasible and effective, many of the reported outcome measures are of limited clinical relevance to diagnostic timeliness.ConclusionsThough limited, evidence suggests that interventions aimed at addressing barriers to timely diagnosis of breast and cervical cancer are feasible in resource-limited contexts. Future interventions need to address clinically relevant measures to better assess efficacy of interventions.PROSPERO registration numberCRD42020177232.
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