Regional AlertDiphtheria hits Lao DPR, prompting two health workers to fight back May 16, 2023By MBDS Team8 May 2023. In December 2022, a single reported case of diphtheria in Lao PDR suddenly escalated into a full-blown outbreak. Soon, there were 60 patients across Huaphanh and Bolikhamxay provinces. Since last outbreak in 2012, vaccination rates had fallen off, leaving a dangerous immunity gap that needed to be closed.