9 June 2021 Since its launch, GLASS has expanded in scope and coverage and as of May 2021, 109 countries and territories worldwide have enrolled in GLASS. A key new component in GLASS is the inclusion of antimicrobial consumption (AMC) surveillance at the national level highlighted in this fourth GLASS report. The fourth GLASS report summarizes the 2019 data reported to WHO in 2020. It includes data on AMC surveillance from 15 countries and AMR data on 3 106 602 laboratory-confirmed infections reported by 24 803 surveillance sites in 70 countries, compared to the 507 923 infections and 729 surveillance sites reporting to the first data call in 2017. The report also describes developments over the past years of GLASS and other AMR surveillance programmes led by WHO, including resistance to anti-human immunodeficiency virus and anti-tuberculosis medicines, antimalarial drug efficacy.