As flu season approaches its peak, good-quality sleep may provide the key to increasing the effectiveness of the flu vaccine, researchers say.

Scientific data has long supported the idea that sleep deprivation leads to reduced immune system capability, according to UC Berkeley alumnus and UCSF researcher Aric Prather, who co-authored a study published in March examining the links between sleep and the flu vaccine. The study found that participants who slept less in the weeks before and after the shot possessed lower levels of flu antibodies in the months following the experiment.

“There’s a lot of literature that supports sleep as this important restorative process; we know that it’s fundamental to our biology,” Prather said. “We know that when you deprive people of sleep, at least acutely, aspects of their immune system that are critical for mounting antibodies to protect us from viruses are reduced.”

In Prather’s study, 83 college students were tasked with keeping sleep diaries for 13 days, and on the third day of this period, they received the flu shot. The researchers discovered that shorter sleep duration correlated with fewer antibodies to one of the three viral strains contained in the vaccine.

More importantly, according to Prather, the study found that getting high-quality sleep in the two days prior to receiving the shot seemed to carry the bulk of the benefit in antibody production.

“There have been a number of studies that have shown a relationship between sleep and how vaccines work,” Prather said. “But we need to understand when sleep is particularly important if we’re going to come up with a guideline.”

Prather added, however, that the work would have to be replicated under more robust conditions before definitive conclusions can be drawn regarding pre-vaccination sleep as an antibody enhancer, a task for which his lab has attempted to secure funding. He and his colleagues also hope to study whether sleep would increase the effectiveness of a future COVID-19 vaccine.

COVID-19 causes many of the same symptoms as the flu, so getting immunized for the flu increases the likelihood that an individual’s symptoms stem from COVID-19, according to Lee Riley, UC Berkeley professor and chair of the infectious disease and vaccinology division. It also keeps testing centers and hospitals from becoming overcrowded.

Prather added that while sleep is important, being mindful of exposure is the most important step that people can take to prevent themselves from getting sick.

“Washing your hands, making sure you’re not around people who are sick, wearing masks, social distancing — all those things that we’re doing now, those same principles for public health, are exactly what you’re doing to protect yourself from the flu,” Prather said. “If you can get some more sleep, that’s great, but honestly, reduce your exposure is the main thing we want to focus on.”