After having worked for non-governmental medical organizations in Afghanistan and Lebanon, and a PhD on the effectiveness of malaria control interventions in Madagascar, Thomas turned his focus back to antimicrobial resistance in low- and middle-income countries and medical microbiology in resources-limited settings.

His other research interests also encompass the aetiology of respiratory infections, epidemiology and genomic surveillance of SARS-CoV-2, social inequities in health access and behaviours, and vector-borne diseases. These all have one thing in common: they aim at tackling global inequities in infectious diseases. Thomas’s research programme on the impact of clinical microbiology on antimicrobial resistance control in rural hospitals aims at evaluating whether different laboratory solutions are feasible and acceptable and their impact on AMR perception by healthcare workers, in the clinical management of infectious diseases, in the effectiveness of AMS programs, in antibiotic use, and in AMR surveillance at the district hospital level. It involves quantitative, qualitative, and mixed methods, as well as implementation research design.