Ninety-eight teachers in the Western Cape have contracted Covid-19, the province's head of the education department Brian Schreuder said.
He said that only people who had direct contact with them via a hug or a hand shake need consider themselves a direct contact for the purposes of isolating or quarantining.
Education MEC Debbie Schäfer said the names of the schools and teachers will not be publicised because once word gets out, principals who are already busy, are swamped with questions and visits.
The teachers and schools also have the right to privacy, she said.
However, if a teacher wants to tell people they have Covid-19, it is their choice as an individual to do so.
If a case is detected at a school it is closed, and sanitised, and may only reopen once a certificate has been issued by the service provider.
Schreuder said a lot went into making sure the schools were ready to reopen, which included ordering 2.4 million masks, litres of sanitiser and over 7 000 digital thermometers for the schools, as well as training the staff and putting posters up.
He acknowledged that it is a stressful time for everybody, and that parents and teachers might be projecting their fears on to children.
He said teachers would also get extra training to make them feel as happy as possible about being back at school, due to their own anxiety about being back at work.
Red Cross Children's Hospital paediatrician Professor Mignon McCulloch said there is "a glimmer of hope" regarding children being less susceptible to the virus and less likely to transmit it to adults.
They must all follow the golden rules: wash hands, sanitise, and do not go to school if feeling unwell.
She said that only 3% of the children at the Red Cross Children's Hospital tested positive for Covid-19, and that of the five children who died one had existing lung problems, and another had a cardiac condition.
Journalists were told that of the 1 787 cases of Covid-19 confirmed in children by June 5, 1 537 were reported before May 29, when schools were still closed. The cases were not linked to the return to school.
South Africa as of Wednesday evening had 55 421 cases.
McCulloch urged teachers to be aware of the anxiety of the Covid-19 pandemic, and to be available to listen to school children when they return if they have problems. She said teachers must listen especially to the very young who may not yet know how to articulate the problems they had during lockdown.
She advised masks over visors to protect children and teachers - both if necessary, but if only one is chosen, the mask should take priority.
Schreuder said that all matric pupils are expected to be back at school and using every possible moment to prepare for their final exams.
He said that due to the coronavirus it would not be possible to catch up on lost work for other grades, and so the syllabus would be trimmed to focus on the important concepts.
He stressed that the carers of children with co-morbidities should be getting advice from their doctors or clinicians for the next date of return - 6 July - on whether they should be home schooled or if it is safe for them to return.