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Antimicrobial resistance (AMR) poses a major threat to global health, limiting the effectiveness of antibiotics and threatening successful treatment of infection. Whilst there is growing recognition of the potential role that vaccines can play in slowing the emergence and spread of AMR, empirical evidence has been somewhat limited.  

Vaccines can combat AMR through both direct effects (preventing infections caused by drug-resistant pathogens) and indirect effects (reducing overall antimicrobial use and thus selection pressure). By preventing infections and reducing antimicrobial use, this not only lowers the likelihood of the emergence of resistance in target pathogens, but also on non-target organisms through reducing the “bystander effect,” as commensal organisms will then also not be exposed to antibiotics. The potential impact of vaccines on AMR is enormous. estimated that optimal use of currently licensed vaccines could prevent over 106,000 AMR-associated deaths, avert 142 billion defined daily doses of antimicrobials, and save $861 million annually in hospital costs.  

summarises new primary evidence on the impact of vaccines AMR generated by 11 Wellcome-funded research projects spanning multiple vaccines and settings. A study in Guatemala showed that rotavirus and PCV vaccination was associated with reduced prevalence of gut carriage of extended-spectrum cephalosporin-resistant Enterobacterales; this appears to have been mediated primarily by a reduction in associated clinical syndrome rather than reduced antimicrobial use. An ongoing cluster-randomised study in Malawi found that both a modified PCV13 schedule (2 +1) and the RTS,S/AS01 malaria vaccine were associated with reduced antimicrobial use and lower prevalence of resistant bacterial isolates in young children; however, use of malaria rapid diagnostic tests was associated with increased likelihood of antimicrobial prescription, presumably after a negative result.  

The in Malawi, Ghana, and Zambia added AMR endpoints to a novel rotavirus vaccine trial and demonstrated that improved rotavirus vaccine efficacy could lead to measurable reductions in antibiotic prescribing and AMR gene carriage in infants. A modelling study utilising a large US healthcare dataset found that influenza accounted for 1–3% of antibiotic prescriptions across age groups, but given the large overall scale of prescribing, even small reductions via vaccination could yield a substantial population-level impact. These studies demonstrated that the “pathway to impact” may differ by local epidemiology, vaccine, local prescribing practises, and other factors.  

Results of these studies were discussed in a two-day workshop in November, along with the policy implications and remaining evidence gaps. Key research priorities identified by the group included strengthening and standardising AMR surveillance, conducting multidisciplinary studies measuring vaccination impact on AMR, capturing AMR outcomes in vaccine trials and observational studies, and understanding the impact of vaccination on AMR in combination with additional control measures. In addition, the need for standardisation of methodologies, better integration of AMR into cost-effectiveness assessments, and alignment of vaccination strategies with national AMR action plans were highlighted.  

Set against an increasingly uncertain research funding landscape, there is an urgent need to better capture the potential value of vaccination programmes in preventing the emergence and spread of drug resistance, and to do this in a standardised and consistent manner. This can lead to greater investment in and higher uptake of life-saving vaccines, which will prevent increasingly difficult to treat infections and extend the clinically useful lifespan of existing antimicrobials.