Vaccination is an integral strategy to combat antimicrobial resistance

Publication summary

Vaccination is an integral part of population-wide strategies to prevent and control antimicrobial resistance (AMR). Through the prevention of disease, vaccines may reduce antibiotic use for suspected or confirmed bacterial infections and reduce the emergence and spread of resistance elements both in humans and animals. Existing bacterial vaccines have shown success in preventing disease attributable to Corynebacterium diphtheriae, Neisseria meningitidis, Haemophilus influenzae type b, Bordetella pertussis, and Streptococcus pneumoniae. This article on the implications of vaccines on AMR delves into who is most likely to benefit from bacterial vaccines, the challenges that AMR and antigen identification pose to vaccine development, and current and investigational vaccine development platforms. The authors say, “Using one of the most effective medical interventions of the last century (vaccines) to rescue another (antibiotics) is a worthwhile endeavor to allow future generations to benefit from both.”

Who this is for

• Immunization campaign managers
• Vaccine developers
• Health policymakers

Key findings

Who benefits from bacterial vaccines?

AMR is a pervasive global problem, and activities to prevent infections and reduce antibiotic use must be tailored and targeted to people who are most at risk of severe illness and death. Recent studies have clarified that the burden of AMR in Escherichia coli and Klebsiella pneumoniae is high around the world, and vaccines that target these bacteria should be prioritized. Vaccines, as a preventative strategy, may have a significant effect in low- and middle-income countries in which access and affordability to effective antimicrobials are limited and where a lack of regulation may not ensure that substandard medicines associated with unsuccessful treatment are removed from the market.

Other populations at increased risk for illness and death attributable to drug-resistant bacterial infections include immunocompromised people and people with comorbidities or chronic illnesses who may require frequent or lengthy hospitalizations or invasive procedures. Children are also high users of antibiotics for confirmed or suspected infections, yet questions around dosing and appropriate use, along with a relative dearth of focus on children’s needs in antibiotic development, mean that vaccines may represent an important way of preventing infections and the risks of unnecessary antimicrobial use for kids.

Challenges posed by AMR and antigen identification to vaccine development

Compared with viruses, bacteria represent a challenge to vaccine development because of their high genetic diversity and the range of infections that might be caused by a particular species. If preventing and reducing AMR is a key role of vaccination, then vaccine developers must consider host responses in a given population, which may pose difficulties when defining a protective immune response triggered by a vaccine in someone who is immunocompromised. 

Antigen identification also raises several questions about the feasibility of bacterial vaccine development. Capsular polysaccharides are a commonly targeted antigen, and the pneumococcal and Haemophilus influenzae type b vaccines are capsular polysaccharide vaccines. The authors use K pneumoniae as an example of how time-consuming and uncertain this process can be, noting that, globally, more than 70 capsular serotypes are associated with the diverse infections caused by K pneumoniae. Thus, a capsule-based multicomponent vaccine for K pneumoniae would likely offer limited strain coverage. Bioinformatics pipelines, when used as a complement to vaccine development, may also help to identify and characterize potential antigens.

Bacterial vaccine platforms

Current approaches to bacterial vaccine development include the use of whole inactivated bacteria, live-attenuated vaccines, and subunit vaccines.

Investigational approaches include nanoparticle use and the development of nucleic acid vaccines, the latter tactic representing a potentially strong opportunity for preventing Group A or B streptococcal disease.

Conclusion

While vaccines hold great promise for preventing bacterial infections and reducing the spread of AMR, the authors caution that vaccines are only a part of an integrated system that should include antimicrobial stewardship, investment in research and development, and a focus on health equity and access. What cannot be overstated, however, is that any activity that prevents infection and reduces AMR will contribute to preserving the effectiveness of other healthcare interventions.