Some data suggests mixing two Covid vaccines can generate better immunity or more antibodies can be a "definite possibility", however, more details are needed to conclude, AIIMS chief Dr Randeep Guleria said.
Dr Guleria said: "This is something that has been looked at in the past - giving one vaccine as the priming shot and another as the booster. Some data suggests mixing vaccines leads to slightly higher side effects, but other data suggests it may lead to better immunity and antibody protection."
Further explaining the need for adequate evidence he added, "One needs more data... a large number of vaccines will be available in the future... you will have Pfizer, Moderna, Sputnik V and Zydus Cadila. Therefore which combination is better is something we don't know at this time... but yes, initial studies suggest it may be an option."
As the government is working on this, results of trials will be available in a few months, he said.
Primary study results of a British study issued last month in The Lancet stated that Participants were given a first dose of the AstraZeneca shot (Covishield) and a second of Pfizer (not yet in India)and reported more mild reactions. Meanwhile, data on potency is pending.
A Spanish study has found the combination to be safe and effective.
However, the AIIMS chief stated that the existing vaccines might not be effective against the new delta plus variant. He cited more data is required to demonstrate the mutated strain's potential immune escape abilities. Despite this doubt, he stressed the importance of getting vaccinated and said fully vaccinated people can get infected yet the severity may be much lesser.
Single-dose providing sufficient protection against the delta variant, he informed that medical research says that one dose can only offer 33 per cent safety and both doses nearly 90 per cent.
Also Read: COVID 19 Second dose due? Here's a checklist for things you should know before getting vaccinated
"It is a cause of concern that the primary dose of the vaccine may not be enough to tackle the 'delta' variant. We might need to give the booster dose much earlier to ensure better safety," he added.
He further informed that the government is closely monitoring the situation arising due to delays plus strain and added that the 'delta' strain is of more primary concern.
"We are very closely monitoring that (the 'delta plus' variant) (but) at the moment 'delta plus' is not the dominant variant in India... the 'delta' variant is. So we need to actively track it... do genome sequencing to see how this variant is behaving in our population and prepare accordingly," AIIMS head said.
India has reported 48 cases of 'delta plus' COVID-19 in 11 states, the centre said on Friday.
Coronavirus third wave in India is unlikely to be as serious as the second wave, Dr Guleria said, adding that amid all the debates on the severity of the third wave, he feels the "subsequent wave will not be as bad."
Warning people to not underestimate the virus, he added: "we need to learn from the second... to deal with the third".
Indicating the same caution, a study by the ICMR and the UK's Imperial College London said the third wave required "extreme scenarios for the abrogation of (existing) immunity" to be as terrible as the second wave of Covid.
India was struck hard by the second wave of Coronavirus with lakhs getting infected on a single day and thousands dying every day due to a shortage of oxygen. At its peak, in early May around 4000 deaths and more than 4 lakh cases were being reported every single day. It also triggered a huge public healthcare crisis. Hospitals struggled with the inflow of infected patients and crucial resources like oxygen, medicines and ventilators were insufficient. Advising a possible complete breakdown of the system that could result from a more destructive third wave of outbreak, Experts had urged the government to improve health infrastructure.
Also Read: Explained: Can Vaccinated & Covid-recovered tests positive for Delta+?
Like other experts, Dr Guleria too has warned against hurrying to lift Covid restrictions, particularly if there is even a slight rise in cases, calling it a red flag for the country with billions of people. “We need to take immediate measures in those areas immediately rather than wait for it to spread," he said.