Sammyj had his booster 4 in 1 and had a very bad reaction to it, my friend that works for a emergency pet hospital, said he could have died, im very glad he got thru it,,I wont be having any more booster for him, but will get the rabies it will be good for 3 years, even though im dreading it..I hope it dont make him sick..yollie had her 6 n 1 and did fine and will have the next set end of the mo.I will get all her puppy shots for sure..I just dont want them making them sick..