I thank the authors for reporting their analyses. The apparent disconnect between knowledge of HCV and HCV infection in Egypt may be an unusual case in the epidemiology of infectious disease.

For example, accurate knowledge of infection risks is inversely associated with HIV infection in sub-Saharan Africa. I analyzed Demographic and Health Survey (DHS) data from 17 sub-Saharan African countries and data from other sources. Here is a summary of my findings in one article (http://www.jidc.org/index...):
“Adults' knowledge of one way to prevent blood-borne HIV transmission—avoiding shared razors—was moderately to strongly inversely related to HIV prevalence in 16 sub-Saharan African countries. Countries in which many respondents displayed such knowledge had low HIV prevalence, while countries in which few respondents had this knowledge had high HIV prevalence. In contrast, adults' knowledge of condom use as an HIV prevention strategy was moderately positively associated with HIV prevalence. At the individual level, respondents who knew sharing razors was a risk factor for HIV transmission were modestly less likely to be HIV-infected than those who did not recall this risk. This tendency was stronger in high-prevalence than in low-prevalence countries, and remained after adjustment for demographic and sexual behavior variables. However, respondents who endorsed condom use as a prevention strategy were mildly more likely to be HIV infected, even after controlling for demographic and sexual behavior variables. In Mali, between 2001 and 2006, knowledge of avoiding shared razors increased substantially as HIV prevalence fell. Furthermore, west, central, and east African countries with low to moderate HIV prevalence had implemented public education campaigns that included a focus on blood-borne transmission risks, but such campaigns were absent from high-prevalence countries in southern Africa.”

I found similar results in DHS data from Mozambique (http://f1000research.com/...). Furthermore, in Mozambique, children of HIV-uninfected mothers were less likely to be infected if their mothers were aware of blood-borne HIV risks than if their mothers were unaware.

Public health officials have a primary duty to warn the public about avoidable health risks. Despite this ethical responsibility and the connection between knowledge of transmission routes and reduced risk of HIV infection, public health officials, researchers, and international funding agencies continue to deprive Africans of such life-saving information.