booster dose
nounMedical Definition of booster dose
: a supplementary dose of a therapeutic agent designed to increase the effectiveness of one or more previously administered doses
When possible, the drug [prednisone] was administered every other day, with booster doses during hemolytic crises. — Russell E. Ware et al., The New England Journal of Medicine,, 3 Oct. 1991
especially
: booster shot
… vaccines may have to receive a booster dose every five years after the original series. — Marsha F. Goldsmith, The Journal of the American Medical Association, 1 June 1984