For the second time this week, parents with children enrolled at London's École élémentaire La Pommeraie learned a staff member had tested positive for COVID-19.

In an email sent to parents Wednesday night, the French-first language school board said it had been notified of the positive case involving what it described as a "partner" working within the school.

"The Middlesex London Public Health Unit is conducting the necessary investigations and will quickly contact those who have been in close contact with the identified case and provide them with instructions to follow," school principal Marie-Josée Corrigan wrote to parents in French.

During a media briefing Thursday afternoon, public health officials with the Middlesex-London Health Unit (MLHU) said the staff member was not at school during the day, but was involved in a program that supervises students after school hours.

"No one has come to work while ill," said Dr. Chris Mackie, the medical officer of health with the MLHU when asked if the staff member was symptomatic "The symptoms developed while at work at the end of shift and nobody has violated protocol here," adding that the person had last supervised students on Sept. 28

Earlier this week, a second positive case involving another staff member was reported at the school. So far, there are no reported cases of children being infected, which Mackie said was reassuring.

"At this point there is no link between the two cases," he said. "They've come on [during] a similar timeline, but we can't find anything that indicates that there's been any contact between the two individuals who have tested positive," Mackie said, adding that currently, this is not considered an outbreak.

Mackie said there are approximately 30 close contacts who are isolating and who have been asked to get tested for the virus.

"At this point we don't have data that would show that it's required to close the entire school, but of course, that is always a consideration and we won't hesitate to do that if we need to."

The health unit learned Tuesday night that a student at Saunders Secondary School had tested positive and the entire class had been quarantined. They did not consider the case high risk however, as it said everyone around the teenager had been wearing masks.

A student at H.B. Beal Secondary School tested positive earlier in September. For a complete list of Ontario schools with positive cases, visit the government's website.