I read an article where an elementary school near me had a Covid outbreak. Officials said that all (or close to all) the students tested positive. Officials said that approximately 50% had vax plus booster. 30% had vax but no booster. So the remaining 20% had no vax. All the cases had mild symptoms or no symptoms. This is a natural experiment with two experimental groups and a control group. Data show that all the groups had the same outcome - Covid infection with mild or no symptoms. No hospitalizations, no ICU cases, no deaths.