Some headteachers have been sent letters threatening legal action from protest groups while others have had pressure from parents.
One school leader told the Standard teachers do not want to put their “heads above the parapet” and discuss vaccination publicly.
“There is lots of anti-vax activity and threatening legal letters going around. They are not even pretending to be parents of children at the school,” they said.
“Schools have done nothing wrong but I worry this might end with people at the gates protesting.”
Geoff Barton, of the Association of School and College Leaders, said: “Many of our members have been receiving letters from various pressure groups threatening schools and colleges with legal action if they take part in any Covid vaccination programme.
“This is extremely unhelpful and we would ask those involved in this correspondence to stop attempting to exert pressure on schools and colleges. The question of whether or not to offer vaccinations to this age group has clearly been thoroughly considered and the decision on whether or not to accept this offer is a matter for families.”