Vaccination, antimicrobial drugs and improved hygiene mean that infectious disease has been overtaken by non-communicable disease (cancer, cardiovascular disease and diabetes) as the main cause of death globally and in the UK. However infections are still a significant health and economic burden to the UK. This POSTnote describes recent trends in infections of particular concern in the UK. It outlines the trends that largely result from the capacity of infectious pathogens (disease causing agents) to develop resistance to existing drugs, the emergence of new infections and the re-emergence of infections linked to health inequalities or other factors. Infections are caused by viruses, bacteria, fungi, protozoa, parasites or prions. The epidemiology (causes, patterns and effects) of infectious disease are determined by the interplay of numerous factors: the individual (sex, age, health status, immunity and behaviour), the pathogen (its pathogenicity and ability to mutate) and the environment (climate, air quality and socio-economic factors such as income, quality of nutrition and housing). Overview of Key Points Infectious diseases are a significant health and economic burden in the UK, accounting for 7% of deaths and annual costs of £30bn. The national immunisation programme is widely considered to be the most effective public health intervention in the UK. There are a number of infections of particular public health concern for the UK for which there are vaccines in the early phases of development. Another area of policy interest is antimicrobial resistance. Few of the most needed new drugs are currently in development. POST is grateful to Public Health England and the Department of Health for supplying the data used in this paper and for reviewing the content.