Professor Judith Breuer is a leading British virologist renowned for her groundbreaking work in pathogen genomics and infectious disease diagnostics. She serves as Professor of Virology at University College London (UCL) and Honorary Consultant Virologist at Great Ormond Street Hospital (GOSH), where she established the UK's first accredited clinical metagenomics service for diagnosing complex infections .

Breuer's research focuses on applying next-generation sequencing and phylogenetics to improve virus diagnostics and understand pathogen evolution. Her team has pioneered methods to sequence whole pathogen genomes directly from clinical samples, bypassing the need for traditional culture or PCR amplification . This work has been instrumental in identifying rare and novel pathogens, particularly in cases where standard diagnostic tests have failed.