No, vaccine doses are based on age not weight.
Children five to 11 years of age will receive the paediatric dose of Pfizer (10 mcg dose). Adolescents 12 years of age and older will receive the 30 mcg dose of the Pfizer vaccine.
Children who receive the paediatric dose (10 mcg dose of Pfizer vaccine) for their first dose and then turn 12 years of age by the time the second dose is due will receive the adult dose (30 mcg dose of Pfizer vaccine).