Bigger gap between 2 doses of Covishield means higher efficacy: Doctors

Patna: The ever-fluctuating gap between the two doses of Covishield has created doubts about its efficacy in the minds of many people. They fail to realise the rationale behind frequent changes in the interval between two shots of the vaccine.

Quinquagenarian Manoj Kumar, who received his first dose of Covishield in March, was expecting to get the second dose in May, but he was informed that he would have to wait till July. “Will the increased gap between two doses not reduce the efficacy of the vaccine?” he asks.

Amid so much confusion, 22-year-old Rashmi Priya has not yet been inoculated. She claims, “I have come to know that I will have to wait at the vaccination centre for several hours to get my first dose of vaccine. By the time I receive the second dose, I may even test positive for Covid-19.”

A few people point out that the gap between two doses of Covishield has been increasing only because of a “shortage of the vaccine”. Health experts, on the other hand, justify the increase in the gap, saying that the vaccine provides safety no matter when its two doses are taken.

The joint director of the Indira Gandhi Institute of Cardiology, Dr A K Ashu, says, “The Covid-19 vaccines are still evolving and are in an experimental stage. With gradual progress in studies, the interval between the two doses will change.”

He adds, “The behaviour pattern of different vaccines varies at different levels, but it has been observed that the greater the interval between the doses, the higher will be the efficacy. If the gap between the two shots is increased, most people may not require the booster dose.”

Quoting different studies, Muzaffarpur-based paediatrician, Dr Arun Shah, says, “It has been revealed that by increasing the interval between two doses, the efficacy of the vaccine is nearly 81%.”

The head of the zoology department in Patna University, Arbind Kumar, also observes that the success of the Covid-19 vaccines can be evaluated only after detailed studies over a period of time. “If there are enough doses available, the second shot should be given at the optimal time because it will ensure people’s safety,” he adds.