Another way of making the point: we did COVID challenge trials on monkeys first, because their immune systems are a decent model for that 80-year-old human's. W

Another way of making the point: we did COVID challenge trials on monkeys first, because their immune systems are a decent model for that 80-year-old human's. Well, a 30-year-old human is an even better model of an 80-year-old human. A challenge trial on young people wouldn't prove everything, but it would give a high-information signal quickly.