It could take up to six months before a sufficient number of people could be vaccinated to break the chain of coronavirus transmission and another six months before life could get close to the pre-Covid days, Professor Randeep Guleria, the chief of Delhi's prestigious All-India Institute of Medical Sciences told NDTV on Wednesday. "I'm hopeful that in the next six months, we will have two things. A sufficient number of people who have got the infection and recovered and have some kind of immunity and people who will get the vaccine," Professor Guleria told NDTV. Together, they should break the chain of transmission of the virus, he added.