Dengue is described as a vector-borne disease with increasing public health significance in tropical countries like India. In this context, examine the role of vaccines in disease

Introduction

• Dengue, transmitted by Aedes mosquitoes, poses a growing public health challenge in India due to urbanisation, climate change, and inadequate vector control.
• While vaccines offer a preventive tool, their role remains complex and evolving.

Role of Vaccines in Dengue Prevention

Reducing Disease Burden

• Vaccines can lower incidence, hospitalisation, and mortality, especially in endemic regions
• Help reduce pressure on healthcare systems during outbreaks

Complementing Vector Control

• Provide an additional layer alongside source reduction, fogging, and surveillance
• Useful in high-transmission urban clusters

Targeted Protection

• Can be prioritised for high-risk populations and endemic areas
• Potential to support outbreak preparedness strategies

Challenges in Effective Dengue Immunisation

Scientific and Immunological Constraints

• Presence of four dengue serotypes (DENV 1–4) complicates vaccine design
• Risk of Antibody-Dependent Enhancement (ADE) leading to severe disease in some cases
• Variable efficacy across age groups and serostatus (previous exposure)

Safety and Efficacy Concerns

• Earlier vaccines (e.g., Dengvaxia) showed limited safety in seronegative individuals
• Need for pre-vaccination screening, increasing complexity

Operational Challenges

• Difficulty in identifying target populations (seropositive vs seronegative)
• Integration into Universal Immunisation Programme (UIP) remains limited
• Cold chain and last-mile delivery constraints

Economic and Accessibility Issues

• High cost of vaccines and screening tests
• Limited availability in public health systems

Public Trust and Awareness

• Vaccine hesitancy due to past controversies and safety concerns
• Lack of awareness regarding benefits and limitations

Way Forward

Advancing Research and Development

• Invest in next-generation vaccines with broader and safer efficacy
• Support indigenous vaccine development

Strategic Deployment

• Use vaccines in high-burden regions with robust surveillance data
• Combine with sero-surveys for informed targeting

Strengthening Health Systems

• Improve disease surveillance, diagnostics, and reporting systems
• Integrate vaccination with vector control programmes

Enhancing Accessibility and Trust

• Ensure affordable pricing and public provisioning
• Conduct transparent communication and awareness campaigns

Conclusion

• Vaccines can play a supportive but not standalone role in dengue prevention.
• A multi-pronged strategy combining vaccination, vector control, and public health preparedness is essential to tackle dengue effectively in India.