Former Vaccine Coordinator for a clinic of 18 doctors here
He's up-to-date (next DTaP due between 4-6 years old, generally done at the 4 or 5yr Well Child Check), the exposure risk was tiny, if at all. I personally wouldn't do it because of the up-to-date status and tiny exposure risk, and I'm one who is freaky about keeping up to date with my vaccines and DD's vaccines.
--Mimi
Mom to Lala (2004), Bonus Mom to Big Sis 1 (1991) and Big Sis 2 (1992)
Grammy to Big Kindy Kid (2011), Big Pre-K Kid (2012),
Grandbaby Appendage (2014), and New Baby Grandboy (summer 2017)