Smile 2 led moviegoers all over the world, and even the film’s main character, to question whether vomit has DNA in it. The sequel begins days after the ending of the first Smile film and sees Joel (Kyle Gallner) pass the Smile Curse onto Lewis (Lukas Gage) before being run over by a truck and killed. Lewis then passes the Curse onto Skye (Naomi Scott), the main character of the movie and a world-famous pop star. In addition to Scott, the cast of Smile 2 includes Dylan Gelula, Rosemary DeWitt, and Peter Jacobson.

https://screenrant.com/smile-2-does-vomit-have-dna/