Why the gap between Covaxin doses has not been extended, Centre explains
The science of vaccines is very new and it is evolving, the Indian Council of Medical Research chief Dr Balram Bhargava has said.
The gap between the two doses of Covid-19 vaccines has become a crucial issue as the Centre has revised the gap between two doses of Covishield twice since the beginning of the vaccination drive in January. First, the two doses were meant to be administered four to six weeks apart. Later, the Centre revised it to four to eight weeks. Now the gap has been increased to 12 to 16 weeks.
However, the gap between the two doses of Covaxin, the vaccine developed by Bharat Biotech, has remained unchanged.
Explaining the difference, Indian Council of Medical Research chief Dr Balram Bhargava has recently said that the decision to extend the gap for Covishield and not to extend the gap for Covaxin has been determined by the effectiveness of the first dose of the vaccine.
The first dose of Covishield results in a greater immunity which remains effective for around 12 weeks. Hence, the decision to delay the second dose has been taken, but no such finding is available for Covaxin, Dr Bhargava said.
Terming it as evolving science, Dr Bhargava said vaccines came for the first time in the world on December 15 and so new developments are coming and will continue to come. "It has been seen that the first dose of Covishield results in a great deal of protection, which can stay around 12 weeks. But you do not achieve a similar kind of protection after the first dose of Covaxin. It is only after both the doses of Covaxin are administered, the protection reaches the optimum level," Dr Bhargava said.
It is the same reason why people recovering from Covid-19 infection are also being advised to delay their vaccination, Dr Bhargava said.