Unbelievably cool RCT of network effects in medicine: 1,676 ppl w first-degree *relatives* w gastric cancer were randomly assigned to a week of antibiotics. Over 14-year follow-up, cancer developed in 1.2% w treatment & 2.7% w placebo. nejm.org/doi/full/10.10… via @NEJM @zakkohane pic.twitter.com/962qLcTC6P