2. HIV/AIDS
Despite its high-profile status and terrible effects, scientists and researchers have still been unable to fully tackle HIV/AIDS. The thing is about the virus that causes the disease is that it's sneaky, slippery and very, very tenacious, making it virtually impossible to fully eradicate from the body. Even when patients are put on a cocktail of antiretrovirals, the virus will simply retreat to the gut to hide out until the danger passes. Here, even the best drugs can't touch it. The good news is that, whilst the virus is laying low, the patient's symptoms subside and they can even be classed as "non-infectious". More good news is that experts still think there could be a way of completely eradicating it. The bad news is that this involves basically luring the virus out of hiding. In doing this, doctors would essentially be giving it free reign, allowing symptoms to run riot and massively increasing the risk of it developing into AIDS. This would be like playing an extremely high-stakes game of chicken with the virus in the hope that we would be able to treat and eradicate it before it causes irreversible damage. Understandably, there are few that are comfortable with playing these high-risk mind games with deadly diseases and so far the cure for HIV/AIDS remains out of reach.