Understanding how socioeconomic inequalities drive inequalities in COVID-19 infections.

Across the world, the COVID-19 pandemic has disproportionately affected economically disadvantaged groups. This differential impact has numerous possible explanations, each with significantly different policy implications. We examine, for the first time in a low- or middle-income country, which mechanisms best explain the disproportionate impact of the virus on the poor. Combining an epidemiological model with rich data from Bogotá, Colombia, we show that total infections and inequalities in infections are largely driven by inequalities in the ability to work remotely and in within-home secondary attack rates. Inequalities in isolation behavior are less important but non-negligible, while access to testing and contract-tracing plays practically no role because it is too slow to contain the virus. Interventions that mitigate transmission are often more effective when targeted on socioeconomically disadvantaged groups.

COVID-19 spread, detection, and dynamics in Bogota, Colombia.

Latin America has been severely affected by the COVID-19 pandemic but estimations of rates of infections are very limited and lack the level of detail required to guide policy decisions. We implemented a COVID-19 sentinel surveillance study with 59,770 RT-PCR tests on mostly asymptomatic individuals and combine this data with administrative records on all detected cases to capture the spread and dynamics of the COVID-19 pandemic in Bogota from June 2020 to early March 2021. We describe various features of the pandemic that appear to be specific to a middle income countries. We find that, by March 2021, slightly more than half of the population in Bogota has been infected, despite only a small fraction of this population being detected. The initial buildup of immunity contributed to the containment of the pandemic in the first and second waves. We also show that the share of the population infected by March 2021 varies widely by occupation, socio-economic stratum, and location. This, in turn, has affected the dynamics of the spread with different groups being infected in the two waves.

Antimicrobial central venous catheters do not reduce infections in pre-term babies.

The studyGilbert R, Brown M, Rainford N et al. Antimicrobial-impregnated central venous catheters for prevention of neonatal bloodstream infection (PREVAIL): an open-label, parallel-group, pragmatic, randomised controlled trial. Lancet Child Adolesc Health 2019;3:381-90.The study was funded by the NIHR Health Technology Assessment programme (project number 12/167/02).To read the full NIHR Signal, go to https://discover.dc.nihr.ac.uk/content/signal-000782/antimicrobial-central-venous-catheters-for-pre-term-babies-do-not-reduce-infections.

Repeat thyroid function tests for healthy older people are not needed.

The studyRoberts L, McCahon D, Johnson O, Haque MS, Parle J, Hobbs FR. Stability of thyroid function in older adults: the Birmingham Elderly Thyroid Study. Published on 28 August 2018 Br J Gen Pract 2018;68:e718-26.This study was funded by the National Institute for Health Research School for Primary Care Research (SPCR).To read the full NIHR Signal, go to: https://discover.dc.nihr.ac.uk/content/signal-000703/repeat-thyroid-function-tests-for-healthy-older-people-are-not-needed.

The effect of different spray liquids on the foliar retention of agricultural sprays by wheat plants in a canopy.

The aim of this work was to examine the effect of liquid properties on spray retention in a range of situations representative of practical pesticide application. Liquids with different physical properties were sprayed with conventional flat-fan and air-induction nozzles onto outdoor-grown wheat plants (Triticum aestivum L cv Axona) at growth stages between GS 22 and GS 35. Since total retention is affected by leaf surface as well as plant growth stage and canopy density, the experiments included spraying both single leaves and groups of plants with different canopy densities. Retention on whole plants was strongly influenced by plant growth and canopy properties. Individual leaf surfaces were not as water-repellent as was found previously for younger indoor-grown plants, reducing the effect of dynamic surface tension on retention. This, combined with the increased probability of droplets hitting foliage in a denser canopy, gave reduced differences in retention between liquids when compared with similar measurements made previously on younger plants. With a leaf area index greater than 7, retention on whole plants was almost independent of liquid. Air-induction nozzles gave lower levels of retention than flat-fan nozzles, with this difference greatest when spraying high dynamic surface tension liquids and at low crop densities.