Health is another area where we all want the best information.
I’m a little surprised that there is no active and well-developed wiki on health information. WikiHealth.com could be promising, if it grows, but it’s very quiet – only 2 edit sessions in the last 90 days. (I looked for other health wikis listed on WikiIndex, but could find no active wikis – that’s an interesting pattern, to look at another day.)
There are other wiki options in health, though. Wikipedia is teeming with information, though it often means wading through a lot of detail, as the articles are not written with a particular focus on health. wikiHow has more practically oriented articles – see their health category.
And of course see Appropedia to look for – and build – information on global public health.