Nepal measles outbreak response immunization during COVID-19: A risk-based intervention strategy

Area of Science:

• Public Health
• Epidemiology
• Immunization Programs

Background:

• Measles outbreaks pose a significant public health threat, exacerbated by concurrent health crises like the COVID-19 pandemic.
• Nepal's National Immunization Programme (NIP) faced challenges in managing measles outbreaks amidst ongoing COVID-19 transmission in 2020.
• Timely and effective outbreak response is crucial to curb measles spread and prevent mortality.

Purpose of the Study:

• To describe the decision-making framework used by Nepal's NIP for implementing measles outbreak response immunization (ORI) during the COVID-19 pandemic.
• To evaluate the effectiveness of the ORI campaign in controlling measles incidence.
• To highlight key factors contributing to the successful implementation of mass vaccination during a pandemic.

Main Methods:

• A logical decision-making framework was developed and applied, integrating data from measles and COVID-19 surveillance, immunization coverage, and program capacity.
• The framework informed 'Go/No-Go' decisions for ORI interventions, reviewed by the National Immunization Advisory Committee (NIAC).
• Outbreak response strategies, including ORI, vitamin A administration, and case management, were implemented in affected areas.

Main Results:

• Measles outbreak response immunization (ORI) was implemented in four districts, alongside ongoing measles-rubella supplemental immunization activities (SIA).
• Over 32,000 individuals were vaccinated during the ORI, achieving 97% coverage.
• Measles incidence decreased by 98% following the ORI, with a 94-fold reduction in daily incidence rate compared to the pre-intervention period.

Conclusions:

• The study demonstrates the feasible application of a simple, data-driven decision-making framework for implementing mass vaccination campaigns during the COVID-19 pandemic.
• Close collaboration between the NIP, immunization partners (WHO, UNICEF), and guidance from NIAC were critical for successful ORI implementation.
• The findings underscore the importance of robust surveillance and adaptive strategies in controlling infectious disease outbreaks in complex public health environments.