Provincial data provides clearer picture of where Manitobans catching COVID-19

New data from the Manitoba government gives a clearer picture of where people may be catching COVID-19 in the community.

Out of the cases linked to outbreaks or clusters between Jan. 24 and June 12, 36.9 per cent were linked to workplaces, and 17.8 per cent were linked to industrial settings.

The data comes from the latest weekly COVID-19 surveillance report from Manitoba Health.
During a news conference last Friday, Dr. Jazz Atwal, deputy chief provincial public health officer, said the province would start including data on possible COVID-19 acquisition and transmission sources in its weekly reports.

Transmission data includes information on places people have visited while they are infectious and may have transmitted the virus to others. Acquisition data includes information on places people visited during the virus incubation period, which is up to 14 days before onset of obvious symptoms.

"In some cases, the possible exposure may be very clear, such as if the person was a close contact to someone who tested positive or if they acquired COVID through travel," Atwal said.

"However, in other cases, there may be multiple possible exposures to COVID-19 for an individual. These cases are determined to be community acquired or unknown acquisition. In those scenarios, we try to learn more about where the person was to see if trends in acquisition or transmission show up."

Other major sources of COVID-19 cases linked to clusters include daycares (9.5 per cent), schools (8.7 per cent), and acute care facilities (7.6 per cent).

The province defines an exposure as when someone was in one of these potential transmission settings while infectious, which is from about two days before symptom onset to until the person is classified as no longer contagious.

According to the data, workplaces, industrial settings, acute care facilities and schools have all made up a smaller proportion of recent cases linked to clusters compared to the previous week, while daycares made up a larger proportion (around 12 per cent compared to 2 per cent the previous week).

The most common place where others were exposed to potentially infectious people was within a household, at 61.5 per cent, followed by social gatherings (11.7 per cent),workplaces (10.3 per cent), transportation (4.6 per cent), and schools (3.5 per cent).

About a quarter of COVID-19 cases have no known source. Of those, the top five possible acquisition settings include households (29.1 per cent), workplaces (16.8 per cent), retail (10.9 per cent), social gatherings (6.4 per cent) and schools (4 per cent).

1st time data released

In January, CBC Manitoba obtained data on transmission sources through a freedom of information request that showed workplaces were the source of 25 per cent of community-linked cases.

This is the first time the province has included data on the proportion of cluster cases occurring in various settings in Manitoba.

It's unclear why the province released the data in the weekly reports at this stage in the pandemic.

"It may just be that they do have a better picture now," said virologist Jason Kindrachuk.

The assistant professor and Canada research chair in emerging viruses at the University of Manitoba said having the information publicly available could act as a helpful risk mitigation guide in a variety of sectors moving forward, especially in advance of any widespread delta variant-driven upticks.

"The data certainly helps us start to tease apart where there are areas that may actually have early indications of transmission, and also give us an idea of focal areas for COVID transmission," he said.

Kindrachuk said some of the trends also suggest we should be doing more random testing in key sectors with higher proportions of clusters or outbreaks.

"The question is going to be as we start to see broader community transmission picking up do we have enough surveillance, do we have enough vaccine coverage that if the [delta variant] does get into those workplaces that we'll be able to stem that transmission before it takes off."