Covexin 8 is a toxiod, So I would not give that with the antitoxin, I would just give the anti toxin incase they have the bug now. Maybe some others can give an opinion on the matter, but all I know is that I once gave 1 and a quarter cc of covexin 8 to a new born and she was dead 6 hours later (coincidence? or did I kill her by giving the covexin 8?, I 'll never truly know). That was the moment in that fawning season I decided I would not give another Vaccination to a new born. I have since vaccinated when the weather is fowl. If the weather is good, I don't worry about it. But my understanding is If you give the toxid and the anti toxin, they may cancel each other out and both be ineffective. Don't hold me to it, but that is my opinion. Maybe others give covexin 8 with no trouble.