So far, the UK has approved four vaccines for use: Pfizer-BioNTech, Oxford-AstraZeneca, Moderna and Janssen; three of which require two doses for maximum protection.

Is Pfizer COVID-19 booster same as original vaccine?

The boosters will be an extra dose of the original vaccine. Manufacturers still are studying experimental doses tweaked to better match delta. There's no public data yet that it's time to make such a dramatic switch, which would take more time to roll out.

What is the difference between Pfizer and Moderna vaccine?

Moderna's shot contains 100 micrograms of vaccine, more than three times the 30 micrograms in the Pfizer shot. And Pfizer's two doses are given three weeks apart, while Moderna's two-shot regimen is administered with a four-week gap.