Could human challenge studies for COVID-19 vaccines be justified in South Africa?

Although human challenge studies (HCSs) have been widely employed in vaccine development for malaria, dengue, typhoid and cholera, the role of this research design in COVID-19 remains controversial. While the potential social value of HCSs in the context of a pandemic is clear, bioethicists are divided on the ethics, given that effective treatment for COVID-19 has eluded us to date. While compelling ethics arguments have been offered on both sides of the debate, scientific and regulatory complexities may not have been fully appreciated. Furthermore, accelerated development of efficacious vaccine candidates in traditional clinical trials has diluted some of the arguments in favour of HCSs. In low- and middle-income country settings, including South Africa, the need for robust patient care conditions for the conduct of HCSs, coupled with considerations such as perceptions of risk, consent processes, remuneration, vaccine hesitancy, fear of exploitation and access to vaccines, makes HCSs challenging to justify

Neutrophil degranulation, NETosis and platelet degranulation pathway genes are co-induced in whole blood up to six months before tuberculosis diagnosis

Mycobacterium tuberculosis (M.tb) causes tuberculosis (TB) and remains one of the leading causes of mortality due to an infectious pathogen. Host immune responses have been implicated in driving the progression from infection to severe lung disease. We analyzed longitudinal RNA sequencing (RNAseq) data from the whole blood of 74 TB progressors whose samples were grouped into four six-month intervals preceding diagnosis (the GC6-74 study). We additionally analyzed RNAseq data from an independent cohort of 90 TB patients with positron emission tomography-computed tomography (PET-CT) scan results which were used to categorize them into groups with high and low levels of lung damage (the Catalysis TB Biomarker study). These groups were compared to non-TB controls to obtain a complete whole blood transcriptional profile for individuals spanning from early stages of M.tb infection to TB diagnosis. The results revealed a steady increase in the number of genes that were differentially expressed in progressors at time points closer to diagnosis with 278 genes at 13-18 months, 742 at 7-12 months and 5,131 detected 1-6 months before diagnosis and 9,205 detected in TB patients. A total of 2,144 differentially expressed genes were detected when comparing TB patients with high and low levels of lung damage. There was a large overlap in the genes upregulated in progressors 1-6 months before diagnosis (86%) with those in TB patients. A comprehensive pathway analysis revealed a potent activation of neutrophil and platelet mediated defenses including neutrophil and platelet degranulation, and NET formation at both time points. These pathways were also enriched in TB patients with high levels of lung damage compared to those with low. These findings suggest that neutrophils and platelets play a critical role in TB pathogenesis, and provide details of the timing of specific effector mechanisms that may contribute to TB lung pathology

Core competencies in critical care for general medical practitioners in South Africa : a Delphi study

BACKGROUND : Despite a high burden of disease that requires critical care services, there are a limited number of intensivists in South Africa (SA). Medical practitioners at district and regional public sector hospitals frequently manage critically ill patients in the absence of intensivists, despite these medical practitioners having had minimal exposure to critical care during their undergraduate training. OBJECTIVES : To identify core competencies in critical care for medical practitioners who provide critical care services at public sector hospitals in SA where intensivists are not available to direct patient management. METHODS : A preliminary list of core competencies in critical care was compiled. Thereafter, 13 national and international experts were requested to achieve consensus on a final list of core competencies that are required for critical care by medical practitioners, using a modified Delphi process. RESULTS : A final list of 153 core competencies in critical care was identified. CONCLUSION: The core competencies identified by this study could assist in developing training programmes for medical practitioners to improve the quality of critical care services provided at district and regional hospitals in SA.http://www.sajcc.org.za/index.php/SAJCCam2024Critical CareSDG-04:Quality Educatio

Could human challenge studies for COVID-19 vaccines be justified in South Africa?

CITATION: Moodley, K., Maasdorp, E. & Rennie, S. 2021. Could human challenge studies for COVID-19 vaccines be justified in South Africa? South African Medical Journal, 111(6):559-562, doi:10.7196/SAMJ.2021.v111i6.15574.The original publication is available at http://www.samj.org.zaAlthough human challenge studies (HCSs) have been widely employed in vaccine development for malaria, dengue, typhoid and cholera, the role of this research design in COVID-19 remains controversial. While the potential social value of HCSs in the context of a pandemic is clear, bioethicists are divided on the ethics, given that effective treatment for COVID-19 has eluded us to date. While compelling ethics arguments have been offered on both sides of the debate, scientific and regulatory complexities may not have been fully appreciated. Furthermore, accelerated development of efficacious vaccine candidates in traditional clinical trials has diluted some of the arguments in favour of HCSs. In low- and middle-income country settings, including South Africa, the need for robust patient care conditions for the conduct of HCSs, coupled with considerations such as perceptions of risk, consent processes, remuneration, vaccine hesitancy, fear of exploitation and access to vaccines, makes HCSs challenging to justify.http://www.samj.org.za/index.php/samj/article/view/13241Publisher's versio

The differential effects of supplementation with fodder from different tree legumes on feed intake and digestibility of nutrients in sheep fed on maize stover

International audienc

Storage quality and marketability potential of bagged silage for smallholder dairy farmers in Zimbabwe

Bagged sole maize and maize–cowpea silages in three bag sizes were assessed at 42 and 282 d post-ensiling for sensory and chemical quality. A survey of dairy farmers on silage use and preferences was conducted in the Chikwaka communal area and Marirangwe small-scale commercial farming area. Only silage dryness changed with time. Percentage neutral detergent fibre significantly changed in 20 kg bags from 58.1 ± 0.75% at 42 d to 52.3 ± 0.86% at 282 d and in 10 kg maize–cowpea bags from 48.6 ± 0.75% to 56.0 ± 0.86%. Percentage crude protein significantly decreased (P < 0.05) for 15 kg (11.8 ± 0.30% to 9.4 ± 0.35%) and 20 kg bags (11.4 ± 0.30% to 8.9 ± 0.35%) for maize– cowpea. All 45 farmers surveyed knew about silage and 90% were feeding it to cows, 53% were making their own and 37% purchased silage. Challenges in making silage included unavailability of forage choppers, lack of requisite resources and inadequate knowledge. Silage unavailability and difficulties in transportation and storage resulted in a low frequency of silage purchases. There was no association (χ2 = 0.18; P > 0.05) between farming system and farmers’ willingness to buy or sell silage, and larger bags were preferred (χ2 = 78.96; P < 0.05). Computed silage costs per tonne were farm-produced sole maize US$57.54, maize–cowpea US$58.59 and bought-in sole maize US$89.80.Keywords: bag silage, dairy, marketing, nutrition, qualit