Instruct: Identify the main category of the given medRxiv paper based on its title.
Query: Regional performance variation in external validation of four prediction models for severity of COVID-19 at hospital admission: An observational multi-centre cohort study
Risk factors associated with severe outcomes of COVID-19: An updated rapid review to inform national guidance on vaccine prioritization in Canada
Does 2x2 airplane passenger contact tracing for infectious respiratory pathogens work? A systematic review of the evidence.
Are probiotics and prebiotics safe for use during pregnancy and lactation? A systematic review and meta-analysis
Inherited basis of visceral, abdominal subcutaneous and gluteofemoral fat depots
The impact of the one child policy on China's infant mortality from 1970-1989: A quasi-experimental study
Non-replication of structural brain changes from Mindfulness-Based Stress Reduction: Two combined randomized controlled trials
The long-term impact of vaginal surgical mesh devices in UK primary care: a cohort study in the CPRD
Surgical activity in England and Wales during the COVID-19 pandemic: a nationwide observational cohort study
Ethnicity and outcomes in COVID-19 in the United Kingdom: a systematic review and meta-analysis
Simulation and predictions of a new COVID-19 pandemic wave in Ukraine with the use of generalized SIR model
The Gene Curation Coalition: A global effort to harmonize gene-disease evidence resources
Data analysis of COVID-19 wave peaks in relation to latitude and temperature for multiple nations
Trends in Racial and Ethnic Disparities in Barriers to Timely Medical Care Among US Adults, 1999 to 2018
Knowledge barriers in the symptomatic-COVID-19 testing programme in the UK: an observational study
Adaptive vaccination may be needed to eliminate COVID-19: Results from a runtime-alterable strain-drift and waning-immunity model
Data-driven Testing Program Improves Detection of COVID-19 Cases and Reduces Community Transmission
Serial interval and basic reproduction number of SARS-CoV-2 Omicron variant in South Korea
Enhancing Cognitive Restructuring with Concurrent Repetitive Transcranial Magnetic Stimulation for Transdiagnostic Psychopathology: A Proof of Concept Randomized Controlled Trial
A prospective study of the protective effect of SARS-CoV-2-specific antibodies and T cells in Moscow residents
Reasons underlying the intention to vaccinate children aged 5-11 against COVID-19: A cross-sectional study of parents in Israel, November 2021
Comparing human and AI performance in medical machine learning: An open-source Python library for the statistical analysis of reader study data
The statistical analysis of daily data associated with different parameters of the New Coronavirus COVID-19 pandemic in Georgia and their short-term interval prediction from September 2020 to February 2021
Progress, stasis, and regression through the hypertension care continuum: Longitudinal evidence from population-based cohort data in four populous middle-income countries
Aerosol Persistence in ICUs: Utilization of Low-cost Sensor Network
Use of machine learning for comparing disease risk scores and propensity scores under complex confounding and large sample size scenarios: a simulation study