Bayesian approaches to distribution regression

Distribution regression has recently attracted much interest as a generic solution to the problem of supervised learning where labels are available at the group level, rather than at the individual level. Current approaches, however, do not propagate the uncertainty in observations due to sampling variability in the groups. This effectively assumes that small and large groups are estimated equally well, and should have equal weight in the final regression. We account for this uncertainty with a Bayesian distribution regression formalism, improving the robustness and performance of the model when group sizes vary. We frame our models in a neural network style, allowing for simple MAP inference using backpropagation to learn the parameters, as well as MCMC-based inference which can fully propagate uncertainty. We demonstrate our approach on illustrative toy datasets, as well as on a challenging problem of predicting age from images

Improved prediction accuracy for disease risk mapping using Gaussian process stacked generalization.

Maps of infectious disease-charting spatial variations in the force of infection, degree of endemicity and the burden on human health-provide an essential evidence base to support planning towards global health targets. Contemporary disease mapping efforts have embraced statistical modelling approaches to properly acknowledge uncertainties in both the available measurements and their spatial interpolation. The most common such approach is Gaussian process regression, a mathematical framework composed of two components: a mean function harnessing the predictive power of multiple independent variables, and a covariance function yielding spatio-temporal shrinkage against residual variation from the mean. Though many techniques have been developed to improve the flexibility and fitting of the covariance function, models for the mean function have typically been restricted to simple linear terms. For infectious diseases, known to be driven by complex interactions between environmental and socio-economic factors, improved modelling of the mean function can greatly boost predictive power. Here, we present an ensemble approach based on stacked generalization that allows for multiple nonlinear algorithmic mean functions to be jointly embedded within the Gaussian process framework. We apply this method to mapping Plasmodium falciparum prevalence data in sub-Saharan Africa and show that the generalized ensemble approach markedly outperforms any individual method

National, regional, and global estimates of anaemia by severity in women and children for 2000-19: a pooled analysis of population-representative data

BACKGROUND: Anaemia causes health and economic harms. The prevalence of anaemia in women aged 15-49 years, by pregnancy status, is indicator 2.2.3 of the UN Sustainable Development Goals, and the aim of halving the anaemia prevalence in women of reproductive age by 2030 is an extension of the 2025 global nutrition targets endorsed by the World Health Assembly (WHA). We aimed to estimate the prevalence of anaemia by severity for children aged 6-59 months, non-pregnant women aged 15-49 years, and pregnant women aged 15-49 years in 197 countries and territories and globally for the period 2000-19. METHODS: For this pooled analysis of population-representative data, we collated 489 data sources on haemoglobin distribution in children and women from 133 countries, including 4·5 million haemoglobin measurements. Our data sources comprised health examination, nutrition, and household surveys, accessed as anonymised individual records or as summary statistics such as mean haemoglobin and anaemia prevalence. We used a Bayesian hierarchical mixture model to estimate haemoglobin distributions in each population and country-year. This model allowed for coherent estimation of mean haemoglobin and prevalence of anaemia by severity. FINDINGS: Globally, in 2019, 40% (95% uncertainty interval [UI] 36-44) of children aged 6-59 months were anaemic, compared to 48% (45-51) in 2000. Globally, the prevalence of anaemia in non-pregnant women aged 15-49 years changed little between 2000 and 2019, from 31% (95% UI 28-34) to 30% (27-33), while in pregnant women aged 15-49 years it decreased from 41% (39-43) to 36% (34-39). In 2019, the prevalence of anaemia in children aged 6-59 months exceeded 70% in 11 countries and exceeded 50% in all women aged 15-49 years in ten countries. Globally in all populations and in most countries and regions, the prevalence of mild anaemia changed little, while moderate and severe anaemia declined in most populations and geographical locations, indicating a shift towards mild anaemia. INTERPRETATION: Globally, regionally, and in nearly all countries, progress on anaemia in women aged 15-49 years is insufficient to meet the WHA global nutrition target to halve anaemia prevalence by 2030, and the prevalence of anaemia in children also remains high. A better understanding of the context-specific causes of anaemia and quality implementation of effective multisectoral actions to address these causes are needed. FUNDING: USAID, US Centers for Disease Control and Prevention, and Bill & Melinda Gates Foundation

Prevalence and causes of vision loss in sub-Saharan Africa in 2015: magnitude, temporal trends and projections

Background This study aimed to assess the prevalence and causes of vision loss in sub-Saharan Africa (SSA) in 2015, compared with prior years, and to estimate expected values for 2020. Methods A systematic review and meta-analysis assessed the prevalence of blindness (presenting distance visual acuity <3/60 in the better eye), moderate and severe vision impairment (MSVI; presenting distance visual acuity <6/18 but ≥3/60) and mild vision impairment (MVI; presenting distance visual acuity <6/12 and ≥6/18), and also near vision impairment (<N6 or N8 in the presence of ≥6/12 best-corrected distance visual acuity) in SSA for 1990, 2010, 2015 and 2020. In SSA, age-standardised prevalence of blindness, MSVI and MVI in 2015 were 1.03% (80% uncertainty interval (UI) 0.39–1.81), 3.64% (80% UI 1.71–5.94) and 2.94% (80% UI 1.05–5.34), respectively, for male and 1.08% (80% UI 0.40–1.93), 3.84% (80% UI 1.72–6.37) and 3.06% (80% UI 1.07–5.61) for females, constituting a significant decrease since 2010 for both genders. There were an estimated 4.28 million blind individuals and 17.36 million individuals with MSVI; 101.08 million individuals were estimated to have near vision loss due to presbyopia. Cataract was the most common cause of blindness (40.1%), whereas undercorrected refractive error (URE) (48.5%) was the most common cause of MSVI. Sub-Saharan West Africa had the highest proportion of blindness compared with the other SSA subregions. Conclusions Cataract and URE, two of the major causes of blindness and vision impairment, are reversible with treatment and thus promising targets to alleviate vision impairment in SSA

Prevalence and causes of vision loss in East Asia in 2015: magnitude, temporal trends and projections

BACKGROUND: To determine the prevalence and causes of blindness and vision impairment (VI) in East Asia in 2015 and to forecast the trend to 2020. METHODS: Through a systematic literature review and meta-analysis, we estimated prevalence of blindness (presenting visual acuity <3/60 in the better eye), moderate-to-severe vision impairment (MSVI; 3/60≤presenting visual acuity <6/18), mild vision impairment (mild VI: 6/18≤presenting visual acuity <6/12) and uncorrected presbyopia for 1990, 2010, 2015 and 2020. A total of 44 population-based studies were included. RESULTS: In 2015, age-standardised prevalence of blindness, MSVI, mild VI and uncorrected presbyopia was 0.37% (80% uncertainty interval (UI) 0.12%-0.68%), 3.06% (80% UI 1.35%-5.16%) and 2.65% (80% UI 0.92%-4.91%), 32.91% (80% UI 18.72%-48.47%), respectively, in East Asia. Cataract was the leading cause of blindness (43.6%), followed by uncorrected refractive error (12.9%), glaucoma, age-related macular degeneration, corneal diseases, trachoma and diabetic retinopathy (DR). The leading cause for MSVI was uncorrected refractive error, followed by cataract, age-related macular degeneration, glaucoma, corneal disease, trachoma and DR. The burden of VI due to uncorrected refractive error, cataracts, glaucoma and DR has continued to rise over the decades reported. CONCLUSIONS: Addressing the public healthcare barriers for cataract and uncorrected refractive error can help eliminate almost 57% of all blindness cases in this region. Therefore, public healthcare efforts should be focused on effective screening and effective patient education, with access to high-quality healthcare

Assessment of the proliferative, apoptotic and cellular renovation indices of the human mammary epithelium during the follicular and luteal phases of the menstrual cycle

Introduction During the menstrual cycle, the mammary gland goes through sequential waves of proliferation and apoptosis. in mammary epithelial cells, hormonal and non-hormonal factors regulate apoptosis. To determine the cyclical effects of gonadal steroids on breast homeostasis, we evaluated the apoptotic index ( AI) determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling ( TUNEL) staining in human mammary epithelial cells during the spontaneous menstrual cycle and correlated it with cellular proliferation as determined by the expression of Ki-67 during the same period.Methods Normal breast tissue samples were obtained from 42 randomly selected patients in the proliferative ( n = 21) and luteal ( n = 21) phases. Menstrual cycle phase characterization was based on the date of the last and subsequent menses, and on progesterone serum levels obtained at the time of biopsy.Results the proliferation index ( PI), defined as the number of Ki-67-positive nuclei per 1,000 epithelial cells, was significantly larger in the luteal phase (30.46) than in the follicular phase (13.45; P = 0.0033). the AI was defined as the number of TUNEL-positive cells per 1,000 epithelial cells. the average AI values in both phases of the menstrual cycle were not statistically significant ( P = 0.21). However, the cell renewal index ( CRI = PI/AI) was significantly higher in the luteal phase ( P = 0.033). A significant cyclical variation of PI, AI and CRI was observed. PI and AI peaks occurred on about the 24th day of the menstrual cycle, whereas the CRI reached higher values on the 28th day.Conclusions We conclude that proliferative activity is dependent mainly on hormonal fluctuations, whereas apoptotic activity is probably regulated by hormonal and non-hormonal factors.Universidade Federal de São Paulo, Dept Gyneol, Mastol Div, São Paulo, BrazilStanford Univ, Sch Med, Dept Neurosurg, Stanford, CA 94305 USAAPC Pathol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Gyneol, Mastol Div, São Paulo, BrazilWeb of Scienc

Prevalence and causes of vision loss in Latin America and the Caribbean in 2015: magnitude, temporal trends and projections

Objective To estimate the prevalence and causes of blindness and vision impairment for distance and near in Latin America and the Caribbean (LAC) in 2015 and to forecast trends to 2020. Methods A meta-analysis from a global systematic review of 283 cross-sectional, population-representative studies from published and unpublished sources from 1980 to 2014 in the Global Vision Database included 17 published and 6 unpublished studies from LAC. Results In 2015, across LAC, age-standardised prevalence was 0.38% in all ages and 1.56% in those over age 50 for blindness; 2.06% in all ages and 7.86% in those over age 50 for moderate and severe vision impairment (MSVI); 1.89% in all ages and 6.93% in those over age 50 for mild vision impairment and 39.59% in all ages and 45.27% in those over 50 for near vision impairment (NVI). In 2015, 117.86 million persons were vision impaired; of those 2.34 million blind, 12.46 million with MSVI, 11.34 million mildly impaired and 91.72 million had NVI. Cataract is the most common cause of blindness. Undercorrected refractive-error is the most common cause of vision impairment. Conclusions These prevalence estimates indicate that one in five persons across LAC had some degree of vision loss in 2015. We predict that from 2015 to 2020, the absolute numbers of persons with vision loss will increase by 12% to 132.33 million, while the all-age age-standardised prevalence will decrease for blindness by 15% and for other distance vision impairment by 8%. All countries need epidemiologic research to establish accurate national estimates and trends. Universal eye health services must be included in universal health coverage reforms to address disparities, fragmentation and segmentation of healthcar

SARS-CoV-2 Omicron-B.1.1.529 leads to widespread escape from neutralizing antibody responses

On 24th November 2021, the sequence of a new SARS-CoV-2 viral isolate Omicron-B.1.1.529 was announced, containing far more mutations in Spike (S) than previously reported variants. Neutralization titers of Omicron by sera from vaccinees and convalescent subjects infected with early pandemic Alpha, Beta, Gamma, or Delta are substantially reduced, or the sera failed to neutralize. Titers against Omicron are boosted by third vaccine doses and are high in both vaccinated individuals and those infected by Delta. Mutations in Omicron knock out or substantially reduce neutralization by most of the large panel of potent monoclonal antibodies and antibodies under commercial development. Omicron S has structural changes from earlier viruses and uses mutations that confer tight binding to ACE2 to unleash evolution driven by immune escape. This leads to a large number of mutations in the ACE2 binding site and rebalances receptor affinity to that of earlier pandemic viruses