The BCG vaccine has limitations, and research to develop new TB vaccines is ongoing. A number of potential candidates are currently in phase I and II clinical trials. Two main approaches are being used to attempt to improve the efficacy of available vaccines. One approach involves adding a subunit vaccine to BCG, while the other strategy is attempting to create new and better live vaccines. MVA85A, an example of a subunit vaccine, currently in trials in South Africa, is based on a genetically modified vaccinia virus. Vaccines are hoped to play a significant role in treatment of both latent and active disease.
What vaccine are researchers trying to improve on?
BCG

It is estimated that in 480 BC, 50 million people lived in the Achaemenid Empire. The empire at its peak ruled over 44% of the world's population, the highest such figure for any empire in history. In Greek history, the Achaemenid Empire is considered as the antagonist of the Greek city states, for the emancipation of slaves including the Jewish exiles in Babylon, building infrastructures such as road and postal systems, and the use of an official language, the Imperial Aramaic, throughout its territories. The empire had a centralized, bureaucratic administration under the emperor, a large professional army, and civil services, inspiring similar developments in later empires. Furthermore, one of the Seven Wonders of the Ancient World, the Mausoleum at Halicarnassus, was built in the empire between 353 and 350 BC.
How many people lived in the Archaemenid Empire in 480BC?
50 million people

On St. George's Night (Estonian: Jüriöö ülestõus) 23 April 1343, the indigenous Estonian population in the Duchy of Estonia, the Bishopric of Ösel-Wiek and the insular territories of the State of the Teutonic Order tried to rid themselves of the Danish and German rulers and landlords, who had conquered the country in the 13th century during the Livonian crusade, and to eradicate the non-indigenous Christian religion. After initial success the revolt was ended by the invasion of the Teutonic Order. In 1346 the Duchy of Estonia was sold for 19,000 Köln marks to the Teutonic Order by the King of Denmark. The shift of sovereignty from Denmark to the State of the Teutonic Order took place on 1 November 1346.
What date did sovereignty shift from the state of Denmark?
1 November 1346