Overheating may cause terminal apnoea and cot death. Rectal temperature and breathing patterns were examined in normal infants at home during the first 6 months of life.

We tested the hypothesis that the febrile stress of routine vaccination would increase central apnoea in normal infants. Twenty‐one normal infants had continuous overnight breathing and temperature recorded at home, before and after 58 routine vaccination episodes. Central apnoea, of at least 5 sec duration, was detected by computer algorithm and confirmed by human inspection. The longest recorded apnoea was 16 sec (n= 1) during 3629 h of sleep. Overnight rectal temperature increased after vaccination (median 0.52°C, 95% CI 0.40, 0.65). Apnoea density reduced on 46/53 vaccination nights (median ‐29%, 95% CI ‐20, ‐37) followed by an increase on subsequent nights (median +10%, 95% CI +1%, +21%). Overall, apnoea density was similar during the 3 nights preceding and 4 nights following vaccination (median +1%, 95% CI +9,‐6). The febrile stress of routine vaccination did not increase central apnoea in normal infants.

No abstract