Urinary cortisol excretion and rectal temperature were measured in 66
infants before and after immunisation against diphtheria, tetanus, per
tussis, and Haemophilus influenzae type b. Immunisation produced a sig
nificant increase of rectal temperature the next night at all ages. In
fants without an adult-like night time body temperature pattern signif
icant increase in urinary excretion night and morning after immunisati
on. Once an adult-like night time body temperature pattern immunisatio
n no longer raised urinary cortisol output.