Detecting an outbreak early is a matter of surveillance systems, laboratory capacity and a willingness to report. Each of those can fail, and each has failed in ways that were later documented in detail.
We report on how outbreaks are detected, verified and contained, and on the international obligations that govern what a country must tell everyone else.
How outbreaks are detected and controlled: surveillance systems, verification, epidemiological investigation, IHR obligations, containment measures and response gaps.
How global immunization programs work: herd immunity, cold chain, delivery systems, WHO and Gavi roles, vaccine safety monitoring and barriers to coverage.