The Barrhaven Martial Arts Centre has issued an open letter to the public regarding a significant COVID-19 outbreak linked to the facility.

At least 45 cases of COVID-19 are connected to the outbreak. The Barrhaven Martial Arts Centre said in its open letter that the first high-risk exposure came on Nov. 22, but they weren't informed until the 26th.

"On Monday, November 22, a child attended our After School Program. The following day, Tuesday, November 23, the child developed cold-like symptoms and stayed home to isolate, and also get tested," the open letter reads. "Come Friday evening, November 26, four full days after the first exposure, we received a call from Ottawa Public Health (OPH) to notify us of a High-Risk contact in the After School Program."

The business says it immediately informed families of the exposure, and almost all of them were affected.

"The following Monday afternoon, November 29, we received more information from OPH indicating several children in the After School Program had developed symptoms and tested positive over the weekend as the virus likely spread on Monday and furthermore Tuesday to Friday," the open letter said.

They were also informed of an exposure linked to an evening kids' Muay Thai class on Nov. 26. Once again, families were contacted. The business chose on Nov. 30 to shut down its children's program temporarily and offer classes over Zoom.

The martial arts centre says the outbreak at their Strandherd Drive location is not linked to a previous high-risk exposure at Gracie Barra Ottawa on City Centre Avenue.

"None of our staff or students were present during the exposure to Gracie Barra Ottawa, November 9 at 5:30 p.m.," the business said in its open letter.

Instead, staff say the four-day delay between the exposure on Nov. 22 and confirmation from OPH on Nov. 26 is responsible for the wide spread of the virus.

"It is extremely unfortunate that one case grew and spread rapidly over the course of a week, under the radar, in our kids program," the open letter said. "With a four-day delay in communication from OPH, we acted as quickly as possible to execute actions recommended by Ottawa Public Health. We cooperated in every way with Ottawa Public Health, and oftentimes contacted families to warn them of the risk before OPH was able to."

In a statement to CTV News Ottawa Wednesday afternoon, Ottawa Public Health said it typically contacts individuals who receive a lab-confirmed positive result within 48 hours after they do the test; however, identification and notification of high-risk contacts "does take time."

"OPH cannot action case and contact management until a lab-confirmed positive result is in our hands. This relies on individuals going to get tested in a timely manner," said OPH.

"Identification and notification of high risk contacts does take time. After an individual develops symptoms, it takes some time to get tested and to receive the test results. It then takes time for OPH to determine who was exposed to the individual that tested positive, and to notify those contacts."

The Barrhaven Martial Arts Centre reopened Monday, following approval from OPH. The facility was also physically inspected Monday. 

The business said it issued the open letter to address what it called unfounded gossip and rumours in the community about the outbreak.

"The simple fact is one case turned to many, due to a variety of factors," the open letter stated. "Despite screening, attendance tracking, cohorting, sanitary practices, the single largest factor the OPH attributes to this outbreak is a delay in response and action. It took four days from the first High-Risk Exposure to the first contact from Ottawa Public Health in regards to High-Risk Exposure."

On Tuesday, Ottawa Public Health did not confirm whether the outbreak at the Barrhaven Martial Arts Centre was linked to an outbreak of COVID-19 at Half Moon Bay Public School. At least 17 cases in students are linked to the outbreak at the school, and the school is closed. Principal Chris Toivonen said Tuesday that the school would remain closed through Friday, at which point OPH will assess whether it is safe to reopen.

Ottawa Public Health says there is "ongoing COVID-19 transmission in Barrhaven" across multiple settings, including Half Moon Bay Public School.

"The increase in cases presently seen in this area is predominantly amongst individuals who have only recently become eligible for vaccination," said OPH.

"Given the unimmunized, or partially immunized status of this population, all other COVID-19 control measures remain of utmost importance. OPH advises that screening, masking, hand hygiene and reducing contact with person(s) outside of your household remain important tools to protect against COVID-19 transmission."

With files from CTV News Ottawa's Josh Pringle