Sometimes people's plans change at the last minute, or they forgot to get their vet slip signed and find out they still need more vaccinations and need to delay. (diamondsintheruff.com)
This could pave the way to develop more vaccinations to give stressed colonies an extra shot at life. (discovermagazine.com)
In some instances, two or more vaccinations several weeks apart must be given to achieve protection. (hqbullies.com)