Sleep as part of immune regulation
Sleep and the immune system interact closely. During sleep, particularly deep slow-wave sleep, the body shifts the balance of immune signaling molecules and supports processes thought to help build lasting immune memory. Sleep loss tends to push immune signaling toward a more inflammatory profile, which is one reason short sleep is studied as a factor in infection and chronic disease.
These are general patterns observed in research rather than guarantees about any one night or any one person.
What studies suggest about sleep and infection
Several studies report that people who sleep too little around the time of vaccination tend to mount a weaker antibody response, and that habitually short sleepers are more likely to develop a cold after controlled exposure to a virus. The exact size of these effects varies between studies and is best read as a meaningful association rather than a precise figure.
This is general educational information about the sleep-immune relationship, not medical advice; do not change vaccination timing or treat illness based on it, and consult a qualified clinician for health decisions.