Billy Quilty

@bquilty.bsky.social

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Infectious disease epidemiologist and modeller postdoc based at Charité Universitätsmedizin Berlin, honourary LSHTM | PhD LSHTM | MSc Imperial College London | Twitter: @BQuilty

Seven heatmaps displaying social contact matrices, stratified by age, setting, ethnicity, and socioeconomic status. Colour gradients indicate the mean number of contacts, with lighter yellows and greens representing higher values and dark purples representing lower values. Panel A shows total contacts by participant and contact age group, highlighting strong mixing between similar ages along the diagonal, and secondary parallel bands representing parent-child interactions. Panels B through E break down these age contacts by setting. Home displays distinct family and intergenerational patterns, Work shows mixing primarily among working-age adults, School shows highly intense mixing restricted to school-age children, and Other settings display general age assortativity. Panel F illustrates total contacts by ethnic group. It reveals strong assortative mixing, with the highest mean contact numbers occurring between individuals of the same ethnicity, specifically within White, Black, and Asian demographic groups. Panel G displays total contacts by NS-SEC socioeconomic classification and life stage. This matrix demonstrates assortative mixing within similar occupational classes, alongside a notably high concentration of contacts among participants and contacts classified as under 17.
4-panel line chart titled "The Student Loan Trap: Whether or not interest is capped at inflation, or thresholds are indexed to inflation, middle earners are squeezed the hardest." The charts map total lifetime repayment (Y-axis, £0 to £120k) against starting graduate salary (X-axis, £25k to £150k) for a £50k Plan 2 loan over 30 years. Top Left: "Current policy: Frozen threshold, Sliding interest up to RPI+3%." Total repayments peak steeply at nearly £120k for salaries around £70k before dropping for higher earners. Lower and middle earners pay significantly more than the original loan. Top Right: "Indexed threshold." The peak shifts right to £80k salaries, maxing near £90k. Bottom Left: "Frozen threshold, Flat interest (RPI only)." Peak drops to £80k for £55k earners. Bottom Right: "Indexed threshold, Flat interest." The flattest curve, peaking near £70k for £70k earners. All panels show a large orange area representing unpaid debt written off after 30 years, and a green area indicating fully repaid loans for higher earners. Middle-income earners consistently hit the highest peak of total lifetime repayments in all four scenarios.
Accidental aRt made in R and ggplot2 when trying to make a figure showing how different S. pneumoniae serotyping and genotyping methods agree with each other.