‘A 3-Month Gap Between Two AstraZeneca Doses Gives Better Protection'

Scientist Andrew Pollard co-developed the AstraZeneca vaccine together with Sarah Gilbert at Oxford University. Speaking to Srijana Mitra Das at Times Evoke, Pollard, head of the Oxford Vaccine Group, shares insights around the Covid-19 shot:

- Srijana Mitra Das

Both India and the UK recently changed the interval between two AstraZeneca doses. What is the ideal time gap?

We have very good data showing strong protection for the first three months between the two doses. A three-month interval produces very good protection — this gets even better with a longer interval from three to four months. A longer time gap gets a stronger immune response after the second dose.

The reason for the UK’s change is the situation posed by the B.1.617 variant and the attempt to improve immunity and curb transmission. But to get the maximum immune response, it’s worth waiting longer. There is a trade-off between getting a high response earlier or waiting longer and getting an even better immune response.

Could you address fears over AstraZeneca and blood clots? And why do diverse countries recommend different age restrictions for your vaccine?

The biggest problem the world is facing now is the Covid-19 virus killing millions of people, with many more expected to succumb in the current waves. If we do a comparison between the risk of the virus and a very rare type of blood clot, the possibility of the latter happening is extremely low – the possibility of being affected by Covid-19 is high.