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n recent decades, the global healthcare landscape has been significantly shaped by the dual challenges of infectious diseases and the rise of antimicrobial resistance (AMR). While antibiotics have revolutionized medicine, saving countless lives, their overuse and misuse have led to the emergence of resistant pathogens, threatening to undo decades of medical progress. In this context, modern immunization policies have emerged as a crucial tool in the fight against AMR. By preventing infections and reducing the need for antibiotics (specially for secondary bacterial complications), immunization not only protects individual health but also serves as an essential component of antimicrobial stewardship.

 

 

 

 

The Growing Threat of Antimicrobial Resistance

 Antimicrobial resistance occurs when bacteria, viruses, fungi, or parasites evolve mechanisms to resist the drugs designed to kill them. According to the World Health Organization (WHO), AMR is one of the greatest threats to global health, food security, and development. Infections caused by resistant pathogens are more difficult to treat, often require more intensive care, and can result in longer hospital stays, increased healthcare costs, and higher mortality rates.

Over-prescription and inappropriate use of antibiotics in both human and animal health are major drivers of AMR. However, less discussed but equally important is the role of infections themselves in driving the need for antibiotics. By preventing infections through immunization, the need for antibiotic treatment can be significantly reduced, thus curbing one of the primary drivers of AMR.

 

 

 

 

 

 

Role of immunization in preventing infections and antimicrobial resistance

Vaccines are one of the most effective tools in modern medicine for preventing infectious diseases. In the context of AMR, immunization plays a critical role in reducing the incidence of infections that would in secondary complications and otherwise possibly require antimicrobial treatment .

For diseases such as pneumococcal disease, influenza (flu), respiratory syncytial virus (RSV), COVID-19, and pertussis, vaccines not only prevent infection but also reduce the need for antimicrobial therapies for possible secondary complications. Here’s an overview of the specific roles:

 

1. Pneumococcal Disease

• Vaccination reduces the incidence of pneumococcal infections, leading to a decrease in antibiotic prescriptions. This helps prevent the emergence and spread of resistant strains. Vaccination reduces the prevalence of multidrug-resistant pneumococcal strains by lowering infection rates and the selective pressure from antibiotic overuse.

 

2. Influenza (Flu)

• Annual flu vaccines protect against the most common circulating influenza viruses, decreasing hospitalizations and severe outcomes, including secondary bacterial infections. Vaccination prevents primary influenza infections that often predispose individuals to secondary bacterial infections, such as pneumonia, and thus reducing antibiotic use. By preventing flu-related bacterial complications, vaccines indirectly lower the demand for antibiotics, mitigating resistance development.

 

3. Respiratory Syncytial Virus (RSV)

• Recently approved RSV vaccines and monoclonal antibodies (e.g., nirsevimab) protect infants, older adults, and high-risk populations from severe RSV infections. Although RSV is a viral infection, it is often misdiagnosed or complicated by bacterial infections, leading to unnecessary antibiotic use. Vaccination minimizes this risk. By reducing RSV-associated bacterial complications, immunization limits inappropriate antibiotic prescriptions, curbing AMR.

 

4. COVID-19

• COVID-19 vaccines reduce the risk of severe disease, hospitalization, and death caused by SARS-CoV-2. Severe COVID-19 cases often involve secondary bacterial infections, which require antibiotics. Vaccines help prevent these complications. Preventing COVID-19 reduces the misuse of antibiotics prescribed during viral outbreaks when distinguishing between viral and bacterial infections can be challenging.

 

5. Pertussis (Whooping Cough)

• The pertussis vaccine effectively protects against Bordetella pertussis infections, particularly in infants and young children. Vaccination decreases the incidence of pertussis, reducing reliance on antibiotics to treat active infections. Preventing pertussis infections lowers the need for antibiotics, thereby reducing the risk of resistance development in these antibiotic classes.

 

 

 

 

 

 

“Immunization strategies are therefore pivotal in both safeguarding individual and public health against specific diseases and addressing the global challenge of antimicrobial resistance.”

 

 

 

Broader Benefits of Immunization

 

• Reduction in Disease Transmission: Vaccines prevent the spread of infections in the community, lowering overall disease prevalence.
• Minimized Diagnostic Uncertainty: Vaccinated populations are less likely to present with vaccine-preventable diseases, reducing the chance of unnecessary antibiotic prescriptions for viral infections misidentified as bacterial.
• Long-Term AMR Mitigation: By lowering the incidence of infections, vaccines reduce the selective pressure that drives the evolution of resistant pathogens.