Coverage Gaps: Routine immunization programs may not reach all children, leaving gaps in coverage that can lead to outbreaks. Outbreak Control: During an outbreak of a vaccine-preventable disease, rapid and widespread immunization through SIAs can help control and contain the spread. Eradication and Elimination: For diseases targeted for eradication or elimination, such as polio and measles, SIAs are essential tools to reach the last few unvaccinated individuals.
