Food intoöerance especially after changing the food fastly is common if you go through fppd changing ypu should change it slowly may be a week or two. Start with mor oöd food and less new food gradually increase ampunt of new food and decrease amount of old food. And in the mean time if he vomited the food probably he dosent tolerate it and ypu should try some other food

Does your dog has any mix from Collie breed? Some breed can have reaction to vaccine. From my point of view in such a cases the vaccine should be separated and be given apart with one week or more days distance. For exampleinstead of a DHPPiL4 T, DHPPil4 one week and other week T vand see if the dog react again or not? If yes then dont vaccinate him anymore. Deworming also tablets are better but make sure he has no sensitivity to medicine.

vomiting ,depending on the age , breed, gender , diet and enviroment ahs different reason . what he puke is gastric acid and since his belly is empty it came out completly foamy. The best option would be to introduce the dog to a vet who do general exam, blood work, fecal exam especially to rule out pancreatitis and other systemic diseases. But till then the best way to reduce the incidences would be : - small portions but more often ( divide his food to 4 small portion on day) - completly hypoallergen diet : chicken breast 1 portion and 2 portion cooked rice - Routinly deworming wish you luck

In such a cases i prefer to vaccine the dog for rabies separelty with one week difference. from the DHPPiL4 . for deworming first let the feces of 3 days be checked by your vet and then decide for deworming although i suggest to deworm prophilactic every 3 months with Flavoured tabs or with panacur