In Syria in 2014, a measles vaccination campaign inadvertently killed fifteen Syrian children after they received a measles vaccine that was reconstituted using muscle relaxants instead of sterile water diluent. Atracurium ampules had been incorrectly included in vaccination packs assembled in one district vaccine center and then distributed to four separate vaccination teams. Five years later, atracurium was again mistakenly used as measles vaccine diluent in Samoa in 2019, directly killing 2 children, reflexively leading to halted measles vaccinations followed by an overwhelming measles outbreak resulting in the deaths of 83 young children due to undervaccination.