Getting a decent night's sleep after your holiday vaccinations could affect whether they work or not, according to a report in the Daily Mail.
While researching how our immune system reacts to vaccines in real-life conditions, experts found that poor sleep could reduce the effectiveness of jabs.
A study showed that adults who got less than six hours of sleep after being given the hepatitis B vaccine developed less antibodies that those who slept for more than seven hours.
Researchers say the findings could lead to doctors warning patients about to be immunised of their sleep patterns affecting their health.
Lead author of the study, Dr Aric Prather, from the University of California, San Francisco, said: 'With the emergence of our 24-hour lifestyle, longer working hours, and the rise in the use of technology, chronic sleep deprivation has become a way of life for many.
'These findings should help raise awareness in the public health community about the clear connection between sleep and health.'
The study looked at adults in good health and how the antibodies reacted to the hepatitis B vaccination.
The 125 people involved in the study were between the ages of 40 and 60, non-smokers and living in Pennsylvania.
The participants were given a first and second dose of the vaccine a month apart, followed by a booster dose six months later and kept sleep diaries.
People who slept less than six hours per night were far less likely to mount antibody responses to the vaccine and were 11.5 times more likely to be unprotected by the vaccine than those who slept for more than seven hours.
'Sleeping fewer than six hours conferred a significant risk of being unprotected as compared with sleeping more than seven hours per night,' said Dr Prather.
'Based on our findings and existing laboratory evidence, sleep may belong on the list of behavioural risk factors that influence vaccination efficacy.'
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