You're discounting the risk from -not- getting vaccinated. We know Zika can severely damage babies' potential. Whooping cough, rubella, measles? They all have t

You're discounting the risk from -not- getting vaccinated. We know Zika can severely damage babies' potential. Whooping cough, rubella, measles? They all have the possibility to damage people long-term (if they don't kill you, which is admittedly not that common anymore, but can happen). And, since humanity has been living with those diseases for a long time, we have a pretty good sense of exactly how bad they are. We know the risks. So, does vaccination make more healthy people, at a population level, than not vaccinating? That's the question that matters, because every action (or inaction) has risks. The evidence is abundant that yes, vaccination has helped us reach closer to our potential. Diseases like polio might even be entirely eliminated, in which case we're trading a few adverse reactions today for a nigh infinite number of saved lives in the future (if future generations don't have to even be vaccinated, it's pure benefit with no cost) There is admittedly a weird philosophical issue, whereby a vaccine does juggle around probabilities: you're trading 1000 people getting sick with measles (say) for 10 people getting sick from the vaccine. But they're (probably) different people. Were the people who got sick harmed? Sure, but if they hadn't gotten the vaccine, they might have been harmed by the disease. It's impossible to to know for certain. But it's what happens at the population level that counts.