An annual flu shot is one of the least controversial and most widely-recommended preventative health measures. In spite of such advice, only a fraction of those who are suggested to get a flu shot actually receive it. We focus on past personal outcomes to understand how individual learning in influences patterns over time using medical claims for a 5% panel sample of Medicare FFS beneficiaries. We find that individuals learn from personal suffering from flu and such learning is conditional on whether they have taken a flu shot in the same flu season. If they did not take a flu shot, having the flu later on encourages them to get the flu shot next year. But if they had the flu shot and still got the flu, their likelihood of getting a flu shot next year is significantly reduced. The 2009 outbreak of bird flu does not break the qualitative pattern of “learning by suffering” but it does change the strength of learning.