Headteacher Andy Hunter called it a “huge disappointment” after students only returned last week.
Samuel Ward Academy in Haverhil, Suffolk, is undergoing a deep clean after five teachers caught the potentially deadly bug, with two more awaiting results.
Five staff at Samuel Ward Academy in Haverhil, Suffolk, have tested positive within the first seven days of welcoming students back and two more are waiting for results
Mr Hunter is hoping to reopen his school tomorrow despite the outbreak.
A school has been forced to shut after a major outbreak of coronavirus among staff.
Anyone who had contact with the infected teachers now has to self-isolate for 14 days.
Two more year groups were due to start back in the classroom today.
The gates at Old Buckenham High School in Norfolk also remained shut today after a member of staff tested positive for Covid-19.
Mr Hunter said: “The safety of pupils and all those who work at the school is my biggest priority.
“I am very disappointed by this disrupted start to the school term.
“I will be looking closely at the systems we put in place to try to understand how the transmission occurred and to make sure we do everything possible to limit the chances of the same thing happening again.
“Obviously this is a huge disappointment after working so hard to get the school back up and running.
“We were delighted that term had started so well last week and were looking forward to the final two year groups starting.”
“We have taken very extensive precautions.
“But I have had excellent support from Public Health England, Public Health Suffolk and Suffolk County Council.
Public Health England, Public Health Suffolk and Suffolk County Council are working with the school to find out how the outbreak happened.
“We are determined to do all we can to stop the further spread of the virus and agree with the precautionary action to close the school.”
A deep clean is to take place at the school.
Further contact tracing will continue and additional pupils and staff may be asked to self-isolate.