Washington, Aug 2 (IANS): A good night's sleep is vital not only for sound health but also for vaccines to work effectively, says a new study.

"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 Americans," said Aric Prather, clinical health psychologist at the University of California - San Francisco, who led the study, while at the Pittsburgh University.

"These findings should help raise awareness in the public health community about the clear connection between sleep and health," Prather was quoted as saying in the journal SLEEP.

To explore whether sleep duration, sleep efficiency, and sleep quality - assessed at home and not in a controlled sleep lab -- would impact immunity to infection, researchers investigated the antibody response to hepatitis B vaccinations on adults in good health. Antibodies are produced by the immune system to identify and neutralize foreign objects such as viruses and pathogens.

The study involved 125 people (70 women, 55 men) aged between 40 and 60 years. All were non-smokers in relatively good health, and all lived in Pennsylvania - the study was conducted at the University of Pittsburgh, according to its statement.

Each participant was administered the standard three-dose hepatitis B vaccine; the first and second dose were administered a month apart, followed by a booster dose at six months. Antibody levels were measured prior to the second and third vaccine injection and six months after the final vaccination to determine whether participants had mounted a "clinically protective response."

All the participants completed sleep diaries detailing their bedtime, wake time and sleep quality, while 88 subjects also wore electronic sleep monitors known as actigraphs.

The researchers found that people who slept fewer than six hours on average per night were far less likely to mount antibody responses to the vaccine and thus were far more likely (11.5 times) to be unprotected by the vaccine than people, who slept more than seven hours on average.

Sleep quality did not affect response to vaccinations. Of the 125 participants, 18 did not receive adequate protection from the vaccine.

"Sleeping fewer than six hours conferred a significant risk of being unprotected as compared with sleeping more than seven hours per night," the scientists wrote