Informal surveillance has limitations that are exacerbated by newsroom constraints. During the global H1N1 pandemic, significantly fewer infectious disease events were recorded by HM's informal surveillance system. Crowdout poses a risk for epidemiological surveillance since decreased relative surveillance may postpone reporting of outbreaks. Moreover, crowdout during H1N1 showed that this phenomenon can endure for long time periods. However, regional outbreaks like cholera in Haiti or E. coli in Germany do not appear to affect informal surveillance on a global or regional scale.