Future waves of drug-resistant bloodstream infections are expected to rise significantly across Europe, driven largely by the continent’s shifting demographics, a new study reveals. Researchers project that the growing elderly population will disproportionately bear the burden of antimicrobial resistance (AMR), a finding that reframes the public health challenge as one linked not only to evolving pathogens but also to fundamental changes in population structure.
The landmark analysis, published in PLOS Medicine, moves beyond traditional surveillance to forecast the trajectory of AMR through the middle of the century. By integrating over a decade of clinical data with population projections, the study provides a detailed map of a future where age and sex are critical determinants of risk. The findings suggest that without accounting for the profound impact of an aging populace, public health strategies may fail to protect the most vulnerable and miscalculate the resources needed to combat this escalating threat.
A New Model for Forecasting Resistance
The research team, led by scientists at the London School of Hygiene and Tropical Medicine, developed a sophisticated computational model to predict future AMR trends. This work distinguishes itself from previous efforts by combining microbiological data with detailed, country-specific demographic forecasts, offering a more nuanced view of the challenge ahead.
Massive Dataset Informs Projections
The foundation of the study was an enormous dataset encompassing more than 12 million blood infection susceptibility tests. The data was collected from routine clinical diagnostics in 29 European countries between 2010 and 2019. This vast repository of real-world evidence provided a granular picture of which bacteria were causing bloodstream infections and which antibiotics they were resistant to, forming a robust baseline for projecting future trends.
Integrating Age and Sex Data
The model’s key innovation was its analysis of resistance patterns stratified by patient age and sex. By applying these observed patterns to United Nations population projections through 2050, the researchers could estimate how changes in the number of older adults and the balance of men and women would alter the total burden of resistant infections. This approach revealed that demographic factors are not merely incidental but are powerful drivers of the future AMR landscape.
The Disproportionate Impact on Older Adults
One of the most unambiguous conclusions from the modeling is that older Europeans will face the steepest rise in resistant infections. The study projects the most dramatic increases in bloodstream infections for adults aged 74 and older, a stark contrast to trends in younger populations.
For younger cohorts, the incidence rates of these serious infections are expected to either stabilize or, in some cases, decline. The escalating risk for the elderly is likely compounded by factors such as weakened immune systems, a higher prevalence of underlying health conditions, and increased contact with healthcare settings, all of which create more opportunities for difficult-to-treat pathogens to take hold. The findings underscore that as Europe’s population ages, its collective vulnerability to AMR will inherently increase, placing greater strain on healthcare systems.
A Growing Gender Gap in Infection Rates
The analysis also uncovered significant differences in AMR burden between the sexes, with men projected to be more affected than women. According to the projections, men will experience a greater increase in drug-resistant bloodstream infections for six of the eight major bacteria-antibiotic combinations that the researchers analyzed. This sex-based disparity highlights a crucial variable in AMR risk that has often been overlooked in broader public health discussions and projections.
The study did not investigate the underlying causes for this gender gap, but it suggests that any comprehensive strategy to monitor and combat AMR must consider sex as a key biological variable. Failure to do so could result in public health interventions that are not effectively targeted to the individuals most at risk.
Substantial Disparities Across Nations
The forecast shows that the future AMR burden will not be distributed evenly across the continent. The researchers found what they termed “huge country-level variation” in the projections to 2050. For some bacteria-antibiotic combinations, the model predicted opposing trends in different countries, with the burden expected to rise in one nation while falling in another.
This finding complicates efforts to establish a single, overarching AMR strategy for Europe. It suggests that national and even regional public health agencies must develop tailored interventions based on their specific demographic trajectories and existing patterns of resistance. A one-size-fits-all approach is unlikely to succeed when the nature of the threat varies so significantly from one country to the next.
Implications for Global Health Targets
The study’s projections carry sobering implications for achieving global health goals, such as the United Nations target of a 10% reduction in resistant infections by 2030. The analysis concluded that even with highly effective public health interventions, this goal would only be achievable for approximately two-thirds of the studied bacteria-antibiotic combinations. The powerful underlying momentum from demographic changes makes reducing the overall burden a formidable challenge.
Lead author Gwenan Knight stated that the study shows the future burden of drug-resistant infections will not be uniform, with substantial differences across countries, age groups, and sexes. The researchers emphasized that for AMR projections to be accurate and useful, they must formally account for these demographic realities. Without this deeper understanding, policymakers risk being unprepared for the true scale and nature of the evolving AMR crisis.