Parents have been offered reassurance after four students were hospitalised following reports of "seizures and faints".
Ambulance crews attended Wyvern Academy in Darlington on Tuesday and took four students to hospital.
The North East Ambulance Service said it was called to reports of a pupil having a seizure, and the school in the Eggleston View area of the city has since confirmed the ambulance was initially called to student who was having an epileptic seizure.
Read more: Go here for the very latest breaking news updates from across the North East
As reported by Teesside Live, head teacher Owen Inglis has said two other students with underlying health conditions were aided by emergency services and taken to hospital as a precautionary measure.
The details come after NEAS said crews were called to reports of a patient having a seizure on the school site - and while they were in attendance they were made aware of other patients suffering from seizures and "faints".
In total three patients were taken to hospital by ambulance crews and a fourth was taken to hospital "after the fact" by a parent.
Owen Inglis, of Wyvern Academy, said: "An ambulance was called to the academy at 1pm on February 15 as a result of one student having an epileptic fit.
"This is an ongoing medical condition and the student has had these episodes in school previously.
"As a result, our staff were quick to respond to the situation and call in medical experts meaning the student received the medical attention needed swiftly and effectively.
"While on site, the emergency services aided two other students with underlying health conditions and these students were taken to hospital as a precautionary measure. These students have been discharged by the hospital.
“Another student was taken to hospital after the fact, by a parent, and has also been discharged from the hospital.
“This is an unusual event to take place at the academy but, Wyvern Academy is and remains a safe space for all students, the fact our staff responded quickly and appropriately to the situation ensured the safety of students was key.
"The underlying health conditions faced by these students meant we were already prepared for a situation such as this taking place and our wider school community has not been impacted.
“We have spoken to each of the pupils’ families and are supporting them with these ongoing medical conditions. We are also working with external agencies to provide any additional support which may be required.”
The student with epilepsy remains in hospital for their ongoing medical condition but the other three patients have been discharged, the school has confirmed.
Durham Constabulary previously confirmed they had no involvement in this incident.
A spokesperson for the North East Ambulance Service previously said: "We received a call from a member of staff at Wyvern Academy just after 1pm on Tuesday for a patient who was fitting.
"While the crew attended to treat the patient, we received reports of other episodes of fits or faints in other parts of the school.
"We took three patients to hospital, another was making their own way and a fifth did not require any treatment."
For the latest local news in your area direct to your inbox every day, go here to sign up to our free newsletter
