In the aftermath of a large negative shock, such as an epidemic, retrospective voters evaluate the policy-makers' response and either punish or reward them in elections. A prominent concern during the on-going coronavirus pandemic has been whether politicians concerned about re-election have incentives to impose stringent mitigation measures that may carry high economic costs. On the other hand, voters might also react to the shock itself, no matter what the government does. To understand the effect of epidemic outbreaks on voting, we revisit the 2009 H1N1 outbreak in Mexico. Leveraging detailed administrative data and a difference-in-differences approach, we document a strong, negative relationship between the magnitude of the local epidemic outbreak and the governing party vote share in the 2009 congressional election. The electoral punishment depended on the magnitude of the peak of the epidemic curve but not on its timing, and it occurred independently of the remedial actions taken by the government. Furthermore, we find persistent effects in the 2012 election. Our results indicate that voters are acutely aware of epidemics, responding to them at the ballot box. The findings indirectly suggest that mitigation policies may be politically valuable even if they are costly for the economy.