WINNIPEG -- The province’s director of epidemiology and surveillance defended the way a positive case of COVID-19 is defined, during the fourth day of a constitutional challenge in the Manitoba Court of Queen’s Bench.

Carla Loeppky was questioned in court Thursday morning by Allison Pejovic, a lawyer for Justice Centre for Constitutional Freedoms which is representing seven churches and three individuals. They’re fighting Manitoba’s COVID-19 restrictions, arguing they infringe on charter rights to hold religious and public gatherings and to gather at private homes.

Lawyers argue the public health orders rely too heavily on the results of polymerase chain reaction (PCR) tests.

Loeppky testified the epidemiology and surveillance team she leads receives information from three labs when someone who takes a PCR test is determined to be positive for COVID-19.

Positive tests are referred to regional health authorities for follow-up and case numbers are compiled and shared with the public, Loeppky told the court.

Loeppky testified the information her team receives from individual lab-confirmed cases includes several details including the ordering physician, the date of the test, when the lab test was sent, the result, the reason for the test as well as the individual’s personal health information.

“A lab result does contain a considerable amount of information but it’s considered a starting point,” Loeppky told the court. “It’s certainly not considered an endpoint in terms of what we know about a case.”

“It’s not going to rest on that data alone.”

Pejovic asked Loeppky if there’s any way of knowing how infectious a person is by looking at the lab result without having the CT value (cycle threshold), which shows the number of cycles it takes for the test to identify the virus.

Loeppky told the court her team doesn’t get the CT value from the lab result but added finding out when someone acquired or transmitted the virus is part of the follow-up that public health does through contact tracing and she added cases can also be reviewed with labs.

Pejovic argued the process could result in isolation for people who test positive due to an old infection and their contacts when their risk of infection is very low or non-existent.

Loeppky testified the scenario is possible but unlikely.

“It’s extremely rare that somebody would be treated as a case and that they would be under isolation with their contacts based on an old infection,” Loeppky told the court. “The chance of this happening is so incredibly rare, based on the information that’s available both through the lab and the interview process.”

“A CT value is not going to give you a timing, a date, a timeframe of infection.”

Pejovic argued Loeppky’s department also doesn’t have access to information from a clinical examination.

Loeppky told the court clinical information is collected during the interview with case investigators.

Pejovic suggested the data Loeppky’s unit compiles and then shares publicly doesn’t provide a full picture because it doesn’t contain information about infectivity.

“Wouldn’t you agree with me that it’s not good public health practice to tell the public and the media that there are new cases of COVID-19, without telling them how many are actually infectious?” Pejovic asked Loeppky.

Loeppky disagreed.

“I think we strike a balance between providing really important detail on a day-to-day basis. It covers off information about cases on population level that is valuable and helpful.”

“I don’t think that adding information about infectivity would necessarily be beneficial and it’s certainly not something that we’ve considered.”

Court of Queen’s Bench Chief Justice Glenn Joyal is presiding over the case.

Chief provincial public health officer Dr. Brent Roussin is expected to testify Friday.

The constitutional challenge is scheduled to take place over nine days.