Two Samoas: quarantine versus none
In November 1918 the steamer SS Talune arrived in New Zealand-administered Western Samoa from Auckland carrying influenza-sick passengers. Colonial authorities did not quarantine it, and roughly a fifth of the population died within weeks. Nearby American Samoa, whose governor John Poyer imposed a strict maritime quarantine, recorded no influenza deaths at all, making it one of the clearest natural experiments showing that an administrative decision at the border can be the difference between catastrophe and zero mortality.
