While 10 percent of those infected with TB will progress to active disease over their life time, those who are coinfected with both TB and HIV on the other hand will progress to active TB more rapidly, at the rate of 10 per cent annually and about 60 per cent in their life time, increasing the numbers of people sick with TB
The epidemiology of tuberculosis in Kenya has evolved over the years due to several factors including time, economic factors, environmental factors, and comprehensive control strategies that have been put in place since the National TB and Leprosy Program was launched by the Kenya government in 1980. The downward trend of cases notified in Kenya changed in early nineties when HIV came into the picture after the first case was diagnosed in the country in 1984. Since then, the number of HIV cases reported has continued to increase with a commensurate increase in TB cases notified. However, several control strategies in line with theWHO Stop TB strategy (DOTS) and TB HIV collaborative activities have been adopted and implemented at different levels shaping the trajectory that disease transmission took. The DOTS strategy was introduced in Kenya in 1993 as a pilot and quickly covered the whole country by 1997. In addition, TB HIV collaborative activities were introduced in the 3rd quarter of 2005 to specifically address issues of HIV coinfection.
Although there are recent indications that the cases notified in Kenya have stabilized and began to decline, about 56% of the cases reported still come from three out of 8 provinces in the country. Little work has been done in high burden provinces of Nairobi, Rift Valley, and Nyanza provinces of Kenya to understand the evolving epidemiology of tuberculosis epidemic, and the associated factors which can be addressed to mitigate the effect of TB.