Barriers and facilitators to community acceptability of integrating point-of-care testing to screen for sickle cell disease in children in primary healthcare settings in rural Upper East Region of Northern Ghana.

INTRODUCTION: Sickle cell disease (SCD) remains a public health problem especially in sub-Saharan Africa including Ghana. While pilot initiatives in Africa have demonstrated that neonatal screening coupled with early intervention reduces SCD-related morbidity and mortality, only 50-70% of screen-positive babies have been successfully retrieved to benefit from these interventions. Point-of-care testing (POCT) with high specificity and sensitivity for SCD screening can be integrated into existing immunization programs in Africa to improve retrieval rates. This study explored community acceptability of integrating POCT to screen for SCD in children under 5 years of age in primary healthcare facilities in Northern Ghana. METHOD: This was an exploratory study using qualitative research approach where 10 focus group discussions and 20 in-depth interviews were conducted with community members and health workers between April and June 2022. The recorded interviews were transcribed verbatim after repeatedly listening to the recordings. Data was coded into themes using QSR Nvivo 12 software before thematic analysis. RESULTS: Most participants (70.9%) described SCD as serious and potentially life-threatening condition affecting children in the area. Of 148 community members and health workers, 141 (95.2%) said the screening exercise could facilitate diagnosis of SCD in children for early management. However, discrimination, fear of being tested positive, stigmatization, negative health worker attitude linked with issues of maintaining confidentiality were reported by participants as key factors that could affect uptake of the SCD screening exercise. Most participants suggested that intensive health education (78.3%), positive attitude of health workers (69.5%), and screening health workers not being biased (58.8%) could promote community acceptability. CONCLUSION: A large majority of participants viewed screening of SCD in children as very important. However, opinions expressed by most participants suggest that health education and professionalism of health workers in keeping patients' information confidential could improve the uptake of the exercise.

A retrospective data analysis on prevalence and risk factors for hypothermia among sick neonates at presentation to the neonatal intensive care unit of the Tamale Teaching Hospital.

Neonatal hypothermia, defined as an axillary temperature of <36.5C in a neonate, is common in neonatal intensive care units and is almost universal across all geographic and climatic regions of the world. This is even though environmental temperature is a known risk factor for its occurrence. We conducted a retrospective study in the Neonatal Intensive Care Unit of the Tamale Teaching Hospital (TTH) to document the prevalence and risk factors associated with hypothermia at presentation to the hospital. The study spanned the period from January 2019 to December 2019 and involved all neonates with axillary temperature documented at the time of admission. The prevalence of neonatal hypothermia in this study was 54.76%. Hypothermia was most common in neonates diagnosed with meconium aspiration syndrome (87/105, 82.86%), prematurity and low birth weight (575/702, 81.91%), and birth asphyxia (347/445, 77.98%). Neonates who were delivered vaginally were less likely to develop hypothermia compared to those delivered via Cesarean section. Inborn neonates (delivered in TTH) were 3.2 times more likely to be hypothermic when compared to those who were delivered at home. Neonates with low birth weight and APGAR scores < 7 at 1 and 5 minutes were more likely to be hypothermic. The dry season was found to be protective against hypothermia when compared to the rainy season. The overall mortality rate was 13.68% and the mortality in the subgroup with hypothermia at presentation was 18.87%. Our study documented a high prevalence of hypothermia with higher rates in neonates requiring intervention at birth. It is therefore crucial for perinatal care providers to adhere to the warm chain precautions around the time of birth.

Early life ambient air pollution, household fuel use, and under-5 mortality in Ghana.

INTRODUCTION: Environmental exposures, such as ambient air pollution and household fuel use affect health and under-5 mortality (U5M) but there is a paucity of data in the Global South. This study examined early-life exposure to ambient particulate matter with a diameter of 2.5 µm or less (PM2.5), alongside household characteristics (including self-reported household fuel use), and their relationship with U5M in the Navrongo Health and Demographic Surveillance Site (HDSS) in northern Ghana. METHODS: We employed Satellite-based spatiotemporal models to estimate the annual average PM2.5 concentrations with the Navrongo HDSS area (1998 to 2016). Early-life exposure levels were determined by pollution estimates at birth year. Socio-demographic and household data, including cooking fuel, were gathered during routine surveillance. Cox proportional hazards models were applied to assess the link between early-life PM2.5 exposure and U5M, accounting for child, maternal, and household factors. FINDINGS: We retrospectively studied 48,352 children born between 2007 and 2017, with 1872 recorded deaths, primarily due to malaria, sepsis, and acute respiratory infection. Mean early-life PM2.5 was 39.3 µg/m3, and no significant association with U5M was observed. However, Children from households using "unclean" cooking fuels (wood, charcoal, dung, and agricultural waste) faced a 73 % higher risk of death compared to those using clean fuels (adjusted HR = 1.73; 95 % CI: 1.29, 2.33). Being born female or to mothers aged 20-34 years were linked to increased survival probabilities. INTERPRETATION: The use of "unclean" cooking fuel in the Navrongo HDSS was associated with under-5 mortality, highlighting the need to improve indoor air quality by introducing cleaner fuels.

Ultrasound-assisted extraction (UAE) of Jerusalem artichoke tuber bio-active ingredient using optimized conditions of Box-Behnken response surface methodology.

The method of ultrasound-assisted extraction (UAE) was utilized to extract polyphenols from Jerusalem artichokes tuber (JAT). To determine the ideal values for ultrasound power (UP), extraction time (ET), and temperature (TP), a response surface methodology was utilized. JAT extracts were prepared using UAE and their content of total flavonoids (TFC), total polyphenols (TPC), ferric reducing-antioxidant activity (FRAP), and 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) were determined. Accordingly, optimal settings were obtained where TP = 80.0 °C, ET = 14.99 min, and UP = 99.2 °C. These conditions caused TPC, TFC, FRAP, and % DPPH values to reach 4163.6 mg GAE/kg, 2731.6 mg RE/kg, 2.16 mmol/L, and 85.2% respectively, with general-desirability values of 1.00. In addition, DPPH (R = 0.950) and FRAP (R = 0.962) correlated with TPC, indicating that TPC contributed significantly to antioxidant activity. It was found that UAE extraction yields were higher than conventional extraction yields.

Effect of national immunisation campaigns with oral polio vaccine on all-cause mortality in children in rural northern Ghana: 20 years of demographic surveillance cohort data.

Background: Studies from Guinea-Bissau and Bangladesh have shown that campaigns with oral polio vaccine (C-OPV) may be associated with 25-31% lower child mortality. Between 1996 and 2015, Ghana had 50 national C-OPVs and numerous campaigns with vitamin A supplementation (VAS), and measles vaccine (MV). We investigated whether C-OPVs had beneficial non-specific effects (NSEs) on child survival in northern Ghana. Methods: We used data from a health and demographic surveillance system in the Navrongo Health Research Centre in rural northern Ghana to examine mortality from day 1-5 years of age. We used Cox models with age as underlying time scale to calculate hazard ratios (HR) for the time-varying covariate "after-campaign" mortality versus "before-campaign" mortality, adjusted for temporal change in mortality, other campaign interventions and stratified for season at risk. Findings: From 1996 to 2015, 75,610 children were followed for 280,156 person-years between day 1 and 5 years of age. In initial analysis, assuming a common effect across all ages, we did not find that OPV-only campaigns significantly reduced all-cause mortality, the HR being 0.96 (95% CI: 0.88-1.05). However, we subsequently found the HR differed strongly by age group, being 0.92 (0.75-1.13), 1.29 (1.10-1.51), 0.79 (0.66-0.94), 0.67 (0.53-0.86) and 1.03 (0.78-1.36) respectively for children aged 0-2, 3-5, 6-8, 9-11 and above 12 months of age (p < 0.001). Triangulation of the evidence from this and previous studies suggested that increased frequency of C-OPVs and a different historical period could explain these results. Interpretation: In Ghana, C-OPVs had limited effects on overall child survival. However, triangulating the evidence suggested that NSEs of C-OPVs depend on age of first exposure and routine vaccination programs. C-OPVs had beneficial effects for children that were not exposed before 6 months of age. These non-specific effects of OPV should be exploited to further reduce child mortality. Funding: DANIDA; Else og Mogens Wedell Wedellsborgs Fond.

Cardiovascular disease prevention: Community Based Asset Mapping within religious networks in a rural Sub-Saharan African neighbourhood.

Prevalence of conditions which raise cardiovascular risk, such as hypertension and type 2 diabetes are seeing a dramatic rise in Sub Saharan Africa. A large proportion of these cases remain undiagnosed and there is limited resource to provide patients with self-management support and education once diagnosed. This study aimed to identify and catalogue community-based assets for the purposes of developing and deploying a screening and education programme for cardiometabolic risk factors (diabetes and hypertension) within religious organisations in a local community in a rural Ghanaian context. We utilised a community-based form of participatory research made up of a number of different components including community-based asset mapping and stakeholder consultation, supplemented by 18 in-depth interviews and 10 focus groups with n = 115 service users, to map existing assets with relevance to cardiometabolic health in this setting and context. Thematic analysis of interview and focus group data was performed to identify themes related to successful implementation of health screening. Two stakeholder workshops with local healthcare professionals, faith leaders and health policy makers were delivered to co-produced a prioritised list of recommendations and 'asset map' to aid deployment of mass screening within faith organisations in this context. The findings of this research highlight a number of 'hidden' community assets and motivational mechanisms at an individual, community and institutional levels; these have informed a list of recommendations which have been co-developed with the stakeholder group and local community to support the development of effective screening strategies for cardiometabolic conditions within faith organisations in this context. We have identified key mechanisms and assets which would support a sustainable screening approach designed to engage an underserved community at high CVD risk to promote general community health and well-being.

Birth preparedness and complications readiness among women in disadvantaged rural districts of Ghana.

INTRODUCTION: Essentially all women and babies irrespective of their economic and social status should reach their full potential for health and well-being. The study assessed the readiness of mothers and their preparedness for birth across three disadvantaged rural districts in Ghana. METHODS: A multi-centre quantitative survey from January to December 2018 using a multistage sampling approach was employed. Using a structured questionnaire data from mothers attending antenatal and postnatal clinics in three main ecological zones of Ghana were collected. Women who provided informed consent were consecutively recruited until the sample size was achieved. For categorical data, summary tables, proportions and percentage are presented. Multivariate logistic regression analysis determined the effect of selected characteristics on birth preparedness. Ethics approval was obtained from the Navrongo Health Research Centre. RESULTS: A total of 1058 mothers were enrolled: 33.6%, 33.4% and 33.0% respectively from the Ada west, Upper Denkyira west and Builsa south districts. About 94% of the women had prior knowledge of birth preparedness. Approximately 22.6% (95%CI 20.1, 25. 2) of the mothers were assessed to have poor birth preparedness: 8.0% in Builsa south, 27.8% in Ada west and 31.7% in Upper Denkyira west. Prenatal and postnatal data showed no statistically significant difference in poor preparedness (21.9% vs 23.3%; p-value > 0.05). Maternal age, employment status, religious affiliation and parity were not associated with birth preparedness (p-value > 0.05). Area of study (P < 0.001), educational level (P < 0.016), marital status (p < 0.001) and antenatal contacts (< 0.001) were significantly associated with birth preparedness. CONCLUSIONS: As an important safe motherhood strategy woman should plan their pregnancy and birth well to reduce maternal and neonatal mortality. Policy initiatives should take into consideration area of residence, education, marital status and antenatal contacts of women.

Genetic diversity of rotavirus infection among young children with diarrhoea in the Kassena-Nankana Districts of Northern Ghana: a seasonal cross-sectional survey.

Introduction: diarrhoea disease is a global health concern, persisting as one of the top five causes of morbidity and mortality in children. Viral aetiology of childhood diarrhoea is often associated with rotavirus infection of which preventable vaccines exist. Here we document circulating strains of rotavirus in the Kassena-Nankana Districts of Northern Ghana nearly a decade after the introduction of the rotavirus vaccine. Methods: a cross-sectional survey of children aged 0-60 months was conducted in six health facilities within the Kassena-Nankana Districts. Faecal samples obtained from the children were analysed and characterized for rotavirus detection and genotyping using Semi-Nested Polymerase Chain Reaction. Results: a total of 263 stool samples were analyzed. Out of which 14.8% and 18.6% of the diarrhoea cases were of rotavirus and parasitic etiologies respectively, with 17.4% being co-infections. Almost 27.5% of rotavirus diarrhoeal cases resulted in hospitalization. Household size (p=0.035), location (p=0.018), treatment outcome (p=0.007), vomiting (p=0.039), season (p=0.017) and month of sampling (p=0.000) were significantly associated with rotavirus infection. The rotavirus genotypes identified were G1P8, G3P6, G4P9, G10P6 and G12P8. Rotavirus vaccine-type, G1P8 was absent in Kassena-Nankana West District. Conclusion: the prevalence of rotavirus was low compared to the pre-vaccination era. Also, a new rotavirus strain, G4P9 was identified to be circulating in the study area which calls for surveillance measures and more studies to better understand the situation for appropriate public health intervention.

Pf7: an open dataset of Plasmodium falciparum genome variation in 20,000 worldwide samples.

We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.  We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent.  We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines.  Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website.

Assessing the safety, impact and effectiveness of RTS,S/AS01E malaria vaccine following its introduction in three sub-Saharan African countries: methodological approaches and study set-up.

BACKGROUND: Following a 30-year development process, RTS,S/AS01E (GSK, Belgium) is the first malaria vaccine to reach Phase IV assessments. The World Health Organization-commissioned Malaria Vaccine Implementation Programme (MVIP) is coordinating the delivery of RTS,S/AS01E through routine national immunization programmes in areas of 3 countries in sub-Saharan Africa. The first doses were given in the participating MVIP areas in Malawi on 23 April, Ghana on 30 April, and Kenya on 13 September 2019. The countries participating in the MVIP have little or no baseline incidence data on rare diseases, some of which may be associated with immunization, a deficit that could compromise the interpretation of possible adverse events reported following the introduction of a new vaccine in the paediatric population. Further, effects of vaccination on malaria transmission, existing malaria control strategies, and possible vaccine-mediated selective pressure on Plasmodium falciparum variants, could also impact long-term malaria control. To address this data gap and as part of its post-approval commitments, GSK has developed a post-approval plan comprising of 4 complementary Phase IV studies that will evaluate safety, effectiveness and impact of RTS,S/AS01E through active participant follow-up in the context of its real-life implementation. METHODS: EPI-MAL-002 (NCT02374450) is a pre-implementation safety surveillance study that is establishing the background incidence rates of protocol-defined adverse events of special interest. EPI-MAL-003 (NCT03855995) is an identically designed post-implementation safety and vaccine impact study. EPI-MAL-005 (NCT02251704) is a cross-sectional pre- and post-implementation study to measure malaria transmission intensity and monitor the use of other malaria control interventions in the study areas, and EPI-MAL-010 (EUPAS42948) will evaluate the P. falciparum genetic diversity in the periods before and after vaccine implementation. CONCLUSION: GSK's post-approval plan has been designed to address important knowledge gaps in RTS,S/AS01E vaccine safety, effectiveness and impact. The studies are currently being conducted in the MVIP areas. Their implementation has provided opportunities and posed challenges linked to conducting large studies in regions where healthcare infrastructure is limited. The results from these studies will support ongoing evaluation of RTS,S/AS01E's benefit-risk and inform decision-making for its potential wider implementation across sub-Saharan Africa.

Social and demographic correlates of cardiovascular mortality in the Kassena-Nankana districts of Ghana: a verbal post-mortem analysis.

BACKGROUND: The burden of cardiovascular disease (CVD) in Ghana is rising, but details on its epidemiology are scarce. We sought to quantify mortality due to CVD in two districts in rural Ghana using verbal post-mortem (VPM) data. METHODS: We conducted a proportional sub-hazards analysis of 10 232 deaths in the Kassena-Nankana East and West districts from 2005 to 2012, to determine adult mortality attributed to CVD over time. We stratified results by age, gender and socio-economic status (SES), and compared CVD mortality among SES and gender strata over time. A competing risk model estimated the cumulative effect of eliminating CVD from the area. RESULTS: From 2005 to 2012, CVD mortality more than doubled overall, from 0.51 deaths for every 1000 person-years in 2005 to 1.08 per 1000 person-years in 2012. Mortality peaked in 2008 at 1.23 deaths per 1000 person-years. Increases were comparable in men (2.0) and women (2.3), but greater among the poorest residents (3.3) than the richest (1.3), and among persons aged 55-69 years (2.1) than those aged ≥70 years (1.8). By 2012, male and female CVD mortality was highest in middle-SES persons. We project that eliminating CVD would increase the number of individuals reaching age 73 years from 35% to 40%, adding 1.6 years of life expectancy. CONCLUSIONS: The burden of CVD on overall mortality in the Upper East Region is substantial and markedly increasing. CVD mortality has especially increased in lower-income persons and persons in middle age. Further initiatives for the surveillance and control of CVD in these vulnerable populations are needed.

Effects of low frequency multi-mode ultrasound and it's washing solution's interface properties on freshly cut cauliflower.

This study investigated the effect of single and dual frequency ultrasound washing on freshly cut cauliflower, by pulsed and sweep frequency modes, with or without the addition of zinc acetate (ZA), tea saponin (TS) and ethanol (ET). Results showed that the surface microorganisms were efficiently decreased by sweep dual frequency ultrasound washing. Moreover, the use of 0.5% ZA, or 0.06% TS or 5% ET as washing solution improved the bacterial reduction efficiency. Reducing the interfacial tension, viscosity and contact angle of washing solution may strengthen ultrasound cavitation. Nearly 2.0 log CFU/g natural microorganisms were decreased, and shelf life was extended from 2 to 4-8 days under 4 °C. Physicochemical parameters of bioactive compounds content, enzyme activity, antioxidant ability, freshness were analyzed. Results showed that 0.5% ZA as washing solution of ultrasound washing was beneficial to the quality maintenance during storage period.

Evaluation of pilot implementation of seasonal malaria chemoprevention on morbidity in young children in Northern Sahelian Ghana.

BACKGROUND: In Sahelian Africa, the risk of malaria increases with the arrival of the rains, particularly in young children. Following successful trials, the World Health Organization (WHO) recommended the use of seasonal malaria chemoprevention (SMC) in areas with seasonal peak in malaria cases. This study evaluated the pilot implementation of SMC in Northern Ghana. METHODS: Fourteen communities each serving as clusters were selected randomly from Lawra District of Upper West Region as intervention area and West Mamprusi District in the Northern Region as the non-intervention area. The intervention was undertaken by the National Malaria Control Programme in collaboration with regional health directorates using sulfadoxine-pyrimethamine plus amodiaquine and standard WHO protocols. Before and after surveys for malaria parasitaemia and haemoglobin levels as well as monitoring for malaria morbidity and mortality were undertaken. RESULTS: At the end of the intervention, participant retention was 92.9% (697/731) and 89.5% (634/708) in the intervention and the non-intervention areas, respectively. The proportion of children with asexual parasites reduced by 19% (p = 0.000) in the intervention and increased by 12% (p = 0.000) in the non-intervention area. Incidence rates of severe malaria were 10 and 20 per 1000 person-years follow up in the intervention and comparison areas, respectively with P.E of 45% (p = 0.62). For mild malaria, it was 220 and 170 per 1000 person-years in intervention and comparison area, respectively with PE of - 25% (p = 0.31). The proportion of children with anaemia defined as Hb< 11.0 g/dl reduced from 14.2% (52.8-38.6%) in the intervention area as compared to an increase of 8.1% (54.5% to 62.6) the non-intervention arm, Mean Hb reduced by 0. 24 g/dl (p = 0.000) in the non-intervention area and increased of 0.39 g/dl (p = 000) in the intervention area. CONCLUSIONS: The feasibility and effectiveness of SMC introduction in Northern Ghana was demonstrated as evidenced by high study retention, reduction in malaria parasitaemia and anaemia during the wet season.

Nasopharyngeal carriage of Streptococcus pneumoniae among healthy children in Kassena-Nankana districts of Northern Ghana.

BACKGROUND: Pneumococcal vaccine immunizations may be responsible for alterations in serotype epidemiology within a region. This study investigated the pneumococcal carriage prevalence and the impact of the 13-valent pneumococcal conjugate vaccine (PCV-13) on circulating serotypes among healthy children in Northern Ghana. METHODS: This was a cross sectional study conducted in the Kassena-Nankana districts of Northern Ghana from November to December during the dry season of 2018. Nasopharyngeal swabs collected from 193 participants were cultured per standard microbiological protocols and pneumococcal isolates were serotyped using the latex agglutination technique and the capsular Quellung reaction test. We examined for any association between the demographic characteristics of study participants and pneumococcal carriage using chi-square test and logistic regression. RESULTS: Of the 193 participants that were enrolled the mean age was 8.6 years and 54.4% were females. The carriage rate among the participants was 32.6% (63/193), and twenty different serotypes were identified. These included both vaccine serotypes (VT), 35% (7/20) and non-vaccine serotypes (NVT), 65% (13/20). The predominant serotypes (34 and 11A), both of which were NVT, accounted for a prevalence of 12.8%. PCV-13 covered only 35% of serotypes identified whiles 40% of serotypes are covered by PPV 23. CONCLUSION: Post-vaccination carriage of S. pneumoniae is high and is dominated by non-vaccine serotypes. There is therefore a need for the conduct of invasive pneumococcal disease surveillance (IPD) to find out if the high non-vaccine serotype carriage translates to disease. And in addition, a review of the currently used PCV-13 vaccine in the country would be considered relevant.

Meningococcal vaccines and protein-energy undernutrition in children in the African meningitis belt.

BACKGROUND: Vaccines to prevent meningococcal meningitis in the African meningitis belt include PsACWY, a polysaccharide-only vaccine; and PsA-TT, a polysaccharide-protein conjugate vaccine. Protein-energy undernutrition, a condition where children do not receive enough macro- or micronutrients, is related to increased risk of infectious diseases and poor immune function. Reduced immune function could affect vaccine immunogenicity. We investigated connections between protein-energy undernutrition and vaccine immunogenicity and antibody waning to PsACWY and PsA-TT in children in the African meningitis belt. METHODS: This is a secondary analysis of data collected as part of four clinical trials testing the safety and efficacy of PsA-TT in children in Mali, Ghana, and Senegal. We identified whether anthropometric growth indices (low height-for-age, weight-for-height, or weight-for-age Z-score categories) were related to reduced vaccine-elicited antibody (measured with rabbit complement) from pre- to 1 month post-vaccination, in linear regression models. We also identified whether these growth indices were related to increased waning for vaccine-elicited antibody over time, in linear regression models. RESULTS: A total of 697 children were included in our analysis, of which 350 (50.2%) were female; the mean (SD) age was 1.0 (1.1) years, and 578 (83.0%) received PsA-TT. In linear regression models, no consistent statistical relationship was seen between pre-vaccination anthropometric Z-score categories and vaccine immunogenicity, or decline in antibody over time, for either vaccine, although children with low weight-for-height had a greater decline in antibody from 1 to 6 months post-vaccination. CONCLUSIONS: Our analysis did not find protein-energy undernutrition to be associated with immunogenicity or waning of PsACWY- or PsA-TT-elicited antibody in children living in the African meningitis belt. Future studies should consider measuring antibody titers at additional time points post-vaccination, and for longer periods of time, to determine if the rate of antibody waning over a period of several years is associated with protein-energy undernutrition.

Application of non-thermal pretreatment techniques on agricultural products prior to drying: a review.

BACKGROUND: Most agricultural crops contain high moisture content (80-95% wet basis (wb)) which makes them very susceptible to microbial damage leading to shorter shelf-life and high postharvest losses. The high perishability of these agricultural products requires preservation techniques to prolong their shelf-lives. Drying remains an important component of processing in this regard. Therefore, any pretreatment methods for drying agricultural product that decreases the moisture content and minimizes drying time by conserving the quality of the crop product is of prime significance. This article is a comprehensive review of recent developments of non-thermal pretreatment (NTP) methods. A summary of their significance, emerging and innovative methods of this technology together with its applications and limitations are discussed. This article further examines the environmental impact of NTP techniques. RESULTS: NTP techniques, such as high pressure, ultrasound, pulsed electric field and osmotic dehydration methods are essential operations for pre-dehydration of agricultural products prior to drying. These techniques can avoid the deleterious effects of heat on nutritive value, colour and flavour of agricultural products compared to thermal pretreatments. They also enhance the inactivation of the enzymes, improve energy efficiency and mass transfer, reduce processing time, preserve bioactive compounds, improve drying kinetics and drying rate, minimize enzymatic browning, and enhance product quality. CONCLUSION: These findings will provide a better understanding of different NTP methods and also make available more information for selecting pretreatment techniques for drying of agricultural products. © 2020 Society of Chemical Industry.

Long-term immunity against yellow fever in children vaccinated during infancy: a longitudinal cohort study.

BACKGROUND: A single dose of vaccine against yellow fever is routinely administered to infants aged 9-12 months under the Expanded Programme on Immunization, but the long-term outcome of vaccination in this age group is unknown. We aimed to evaluate the long-term persistence of neutralising antibodies to yellow fever virus following routine vaccination in infancy. METHODS: We did a longitudinal cohort study, using a microneutralisation assay to measure protective antibodies against yellow fever in Malian and Ghanaian children vaccinated around age 9 months and followed up for 4·5 years (Mali), or 2·3 and 6·0 years (Ghana). Healthy children with available day-0 sera, a complete follow-up history, and no record of yellow fever revaccination were included; children seropositive for yellow fever at baseline were excluded. We standardised antibody concentrations with reference to the yellow fever WHO International Standard. FINDINGS: We included 587 Malian and 436 Ghanaian children vaccinated between June 5, 2009, and Dec 26, 2012. In the Malian group, 296 (50·4%, 95% CI 46·4-54·5) were seropositive (antibody concentration ≥0·5 IU/mL) 4·5 years after vaccination. Among the Ghanaian children, 121 (27·8%, 23·5-32·0) were seropositive after 2·3 years. These results show a large decrease from the proportions of seropositive infants 28 days after vaccination, 96·7% in Mali and 72·7% in Ghana, reported by a previous study of both study populations. The number of seropositive children increased to 188 (43·1%, 95% CI 38·5-47·8) in the Ghanaian group 6·0 years after vaccination, but this result might be confounded by unrecorded revaccination or natural infection with wild yellow fever virus during a 2011-12 outbreak in northern Ghana. INTERPRETATION: Rapid waning of immunity during the early years after vaccination of 9-month-old infants argues for a revision of the single-dose recommendation for this target population in endemic countries. The short duration of immunity in many vaccinees suggests that booster vaccination is necessary to meet the 80% population immunity threshold for prevention of yellow fever outbreaks. FUNDING: Wellcome Trust.

Antibody responses to yellow fever vaccine in 9 to 11-month-old Malian and Ghanaian children.

Background: The World Health Organization recommends use of a single yellow fever (YF) vaccine dose for life and fractional doses in outbreaks when there are limited vaccine stocks. In endemic regions, this vaccine is given as part of routine infant immunization programs around 9 months of age. There is a need to better understand immune responses when vaccinating infants particularly in contexts where the child may be malnourished. Methods: Data from 393 Malian and Ghanaian infants who concomitantly received measles and YF vaccines at 9 to 11 months of age were retrospectively analyzed. Response to YF vaccine was examined for association with nutritional status at time of vaccination, sex, age, pre-vaccination titers and season of vaccination. Results: Neutralizing antibodies following vaccination were unaffected by season of vaccination, sex, pre-vaccination titers or nutritional status, though there was a trend to higher titers in males and children with higher height for age z-scores. Seroconversion rates differed significantly between countries (63.5 in Ghana vs. 91.0% in Mali). Conclusion: Longitudinal, prospective studies are needed to optimize the use of YF vaccine in infants in endemic settings. There may be a need for booster vaccinations and to compare various vaccine preparations to optimize the use of available vaccines.