"Mixing vaccines may improve immunity, but need more data": AIIMS Chief

New Delhi (NDTV / June 26, 2021):

Mixing Covid vaccines - which some data suggests could generate better immunity or more antibodies - is a "definite possibility" but more information is needed before a decision can be taken, AIIMS chief Dr Randeep Guleria told NDTV on Saturday morning.

"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," Dr Guleria said.

"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," he explained.

The government is working on this and results of trials will be available in a few months, it has said.

Last month the preliminary results of a British study were published in The Lancet.

Participants were given a first dose of the AstraZeneca shot (Covishield) and a second of Pfizer (not yet in India), and reported more short-lived (but mild) side effects. Data on efficacy is still pending.

A Spanish study reported by news agency Reuters found the combination to be safe and effective.

Dr Guleria also played down fears existing vaccines may be ineffective against the 'delta plus' variant, saying more data is needed to establish the mutated strain's potential immune escape abilities.

He stressed the importance of being vaccinated despite these fears. "... if you are vaccinated fully and come in contact with the virus you may still be infected, but the severity may be much lesser.

He also expressed concern a single dose may be insufficient against 'delta' variants. Published medical research suggests one dose offers 33 per cent protection and both doses nearly 90 per cent.

"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 said, as scientists argue the government's decision to expand interval between two doses.

On the topic of the 'delta plus' variant of COVID-19 Dr Guleria said the government is "closely monitoring" the situation, but the 'delta' strain is of more immediate concern. (Contd.)

https://www.ndtv.com/india-news/coronavirus-india-aiims-chief-dr-randeep-guleria-says-subsequent-wave-will-not-be-as-bad-as-second-wave-2472771

Pfizer Covid-19 vaccine-cum-booster against Omicron variant:

A two-dose Pfizer/BioNTech vaccination provides just 33 per cent protection against infection by the omicron variant of the coronavirus, but 70 per cent protection against hospitalization, according to a large-scale analysis in South Africa released Tuesday. ... Booster dose of Pfizer’s COVID-19 vaccine neutralizes Omicron variant, company says.

https://www.msn.com/en-ca/health/medical/pfizers-vaccine-70percent-effective-against-hospitalization-from-omicron-study/ar-AARNJX2