The paediatric Pfizer BioNTech vaccine is the same formula, the only difference is that children five to 11 years will get a lower dose (10 mcg) than people aged 12 and over (30 mcg). This is because children five to 11 years have smaller bodies and a stronger immune response, so they only need a small amount of vaccine to get the same protection. The vaccine will be given to children in two doses (10 mcg each).