The Ghana Health Service (GHS) and the Ghana Education Service (GES) have agreed to lock down Achimota School for the next two weeks.
As per a directive to the School's authorities, no one will be allowed in or out of the school.
This follows the recording of the fast-spreader Delta variant of Covid-19 among some infected students.
About 135 students tested positive for the new variant though 89 later recovered.
Authorities were alerted by the outbreak of the viral disease in the school after three students were taken ill between Monday, June 14 and Wednesday, June 16 for influenza-like symptoms.
But this later turned out to be Covid-19.
As of Saturday, July 3, 843 students and staff had been sampled.
Among these, 348 are boarding students, 459 are day students and 36 teaching and non-teaching staff.
According to the GHS, results available for 550 samples indicated that total positive was 135 with 293 pending as of Saturday, July 3 and the rest negative.
That same day samples of more day students were taken.
The latest directive means day students would have to remain home for the next two weeks as well.
"We are not going to allow any visitation in the school for the next two weeks. The day students are going to be kept at home for the next two weeks, while those who are positive are going to be kept in isolation," Director of Public Health at GHS Dr Franklin Asiedu Bekoe said in an interview with Accra-based Joy FM.