No, I don't do titers at all since they're unable to really tell you anything substantial. Bc remember:
*You can have a positive titer, yet have no cellular immunity (humoral immunity only in this case)
*You can have a negative titer, and yet HAVE cellular immunity (but there is no test for cellular immunity)
The only super helpful thing a titer can do is, for example, when it's used for a newly admitted shelter or rescue dog etc -- bc you can do a titer and then see if perhaps the animal has had a particular shot in the past, therefore negating the need to vaccinate yet again at that time (avoids overvaccination).
With my kiddos, I really do choose to trust the DOI's - which are well beyond 3 years and instead are 7yrs-lifetime for most vaccinations.
As far as 1/2 doses, I don't think we can assume / know anything at this time. Theoretically though, with the way immunity works -- if a 1/2 dose can trigger the response - then it shouldn't really make any difference to longevity of the response. But we shall see
! Awesome study, it's about time!!!!
With rabies, I do every 3 yrs as there is no choice.