JCoSS switched an open evening for prospective parents to a digital meeting in the wake of rising Covid numbers among teenagers.
By early October around one in 15 children in England aged from 11 to 16 were estimated to have the virus by the Office of National Statistics.
A JCoSS spokesman said the school had been advised “against holding large-scale events in order to keep the community, staff and students safe”.
Additional measures have been introduced for two weeks, including daily lateral flow tests for staff and students and wearing masks in communal spaces and classrooms.
A large percentage of students had signed up for vaccination.
Kantor King Solomon High School said incidence of Covid had been “steadily increasing”. Headteacher Hannele Reece said, “We have put in local controls such as temporary stops on extra curricular clubs for specific year groups to reduce contact.”
Joshua Rowe, chairman of Manchester’s King David School, said “So far we have been pretty lucky” with just five children testing positive on Monday.
Yavneh College in Hertfordshire had some staff and children with the virus but numbers were “pretty stable — if anything reducing.”