We give them one day off then back to full work
I don't "work" my horses after they have just been vaccinated but I do ride them. I just give them a long rein and just hack for that day.
Funny story once my horse's neck was so sore after vaccinations that he couldn't walk straight for 3 days. I still rode him at the walk and trot on a loose rein to try to regain his range of motion faster tho.
I would give him some time or a day.
I give my horse a day off then do a light ride when I get back on
I give my horse about 2-3 days off, because they're neck gets sore from the needle, as well they might not be feeling too well.
Vaccinations work by injecting a small amount of the disease so that the horses can develop the antibodies to fight it off. This means they might be a bit sick for a few days after, so they need rest because a lot of their energy will be going to fighting off the disease
That's better not to rid him, at least not working during the 2 or 3 first days after the vaccin, or complet rest the first day and soft work the following days. Many horses are like us, tired and as Tessy said, a bit sick and that's better for them to have some rest :)
I wouldn't, my vet told me that they could be a bit stiff in the neck, like us they can be softly sick so I wouldn't rid :)