It’s unclear. But as Shin Jie Yong reports, in a 2019 review published in the journal Clinical Microbiology Reviews, pediatric infectious disease specialists at the University of Melbourne, Petra Zimmermann, MD, PhD and Nigel Curtis, outlined variables that affect how the immune system responds to a vaccine. These factors included things that people don’t have control over, like age and genetics. But there were a few behavioral factors highlighted by the researchers that are technically modifiable: sleep, smoking, and alcohol intake. Read on to learn more.