A single dose strategy was used during an outbreak in Zambia in 2015-16, but this first dose was then followed up with a second dose after 6 to 8 months. I was also used in Haiti in 2016-17 following the hurricane. While the delayed second dose strategy has been used and will likely continue to be used during outbreaks or during humanitarian crises, there is no feasible way to assess the relative effectiveness against clinical cholera comparing a two-week interval with a delayed second dose strategy.