Extending vaccine intervals may leave you vulnerable to variants: Dr Fauci

The decision to increase the gap between two doses of Covishield is said to have been taken amid acute vaccine shortage

Vaccination against Covid-19 is the key to fight the infection and extending jab intervals could leave the population vulnerable to one of the Covid-19 variants, according to Dr Anthony Fauci, medical advisor to the US President.

In a conversation with NDTV, Dr Fauci said, “The ideal interval between doses for mRNA vaccines is three weeks for Pfizer and four for Moderna.” Responding to a question about the revised vaccination guidelines by the Indian government, he said, “The problem with extending intervals is that you become vulnerable to variants.”

"... and we've seen that in the UK, where they extended that interval, in that period you can get infected by the variants. So, we recommend staying on schedule," Dr Fauci added.

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For the second time in three months, the Indian government on May 13 extended the gap between the doses of Serum Institute of India-manufactured Covishield vaccine from six-eight weeks to 12-16 weeks. Previously, in March, the gap was increased from 28 days to six-eight weeks “for better results”.

While the increase in gap between two doses of Covishield has been linked to better efficacy, the decision is said to have been taken due to an acute vaccine shortage.

In an exclusive interview with ANI last month, Dr Fauci commented on the increase in the Covishield gap, saying, “When there's vaccine shortage, extending duration between 1st and 2nd dose to get more people to get 1st dose is a reasonable approach. Unlikely that a long delay would have a negative effect on vaccine efficacy. I wouldn't refer to it as a cover-up.”

Dr Fauci stressed on the importance of vaccinating more people in a short period of time to avoid getting infected from the ‘delta’ variant -- which is said to be 40- 50 per cent more infectious.

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"The Delta variant, that is dominant in many states in India, spreads much more readily and efficiently from person to person. So any country that has the Delta variant should be concerned that there will be a surge of infections, particularly, if that particular country does not have a substantial proportion of their people vaccinated. We've seen that when the Delta variant spreads among non-vaccinated people, it can become dominant very, very quickly. That's what is going on in the UK -- the Delta variant is taking over. It is close to 90% dominant now," he told NDTV.

Recent studies by AIIMS and NCDC suggest that the Delta variant may be able to infect fully-vaccinated people.