Essential medicines

The list of essential medicines is a listing of drugs compiled by the WHO. The list contains a number of drugs, which cover the basic needs of a society. The drugs on the list should be easy to get, and affordable. The list was first published in 1977. It is reviewed every two years. In 2003, 156 countries have joined the effort. As of 2016, over 300 different drugs and vaccines are on the list. About 95 percent of the drugs and substances on the list are not covered by patents, which means that generic drugs using the substance indicated can be produced easily.
There are two major problems with the list: First, there are a number of diseases which mainly occur in developing countries. Many people there cannot afford to pay high prices for drugs, which means pharmaceutical companies are not interested in developing new drugs for such diseases. Examples for such diseases are malaria or tuberculosis. The second problem is that certain drugs on the list are patented, and they are often expensive. Examples for the second kind of drugs are those used to treat AIDS.
According to a study done by the world bank, about a third of the world's population does not have access to these drugs.