बेयो प्राय 15 बोसोरफोरनि थाखाय मुलै - होजानाय बैसोरनि 70 % फ्रामाव जौगाफुनाय ति बि नि गिनांनायखौ खमायो ।
It reduces the risk of developing TB in about 70 of those vaccinated for approximately 15 years .