MIDDLESEX CENTRE, ONT. -- The Middlesex-London Health Unit (MLHU) has declared a community outbreak after 22 COVID-19 cases were linked to a series of student social gatherings.

Health officials say 22 post-secondary students, mostly at Western University, who attended at least 10 private gatherings held last week have tested positive.

Western University has confirmed its students are involved and said while most live off campus, three live in residence and were immediately moved into isolation outside of the residence.

The get-togethers happened in London homes between March 2 and March 6.

The health unit has confirmed that sorority and fraternity organizations at Western were involved, but did not provide further details on where the gatherings were held and how many people may have attended.

Investigators are still trying to determine close contacts of those who have tested positive, but are expecting to have reached everyone in the next 24 hours.

MLHU Medical Officer of Health Dr. Chris Mackie says, "When people are engaged in close contacts indoors, without masks, they are putting themselves and others at risk of COVID. They are potentially contributing to the spread of this pandemic."

He also raised concerns about the possibility of people gathering for upcoming St. Patrick's Day and Easter festivities.

"If people bring their large groups of loved ones together the way we traditionally do, or go celebrate St. Patrick's Day, for example, in large groups, we will see large outbreaks of COVID-19."

He is recommending people have safe, small outdoor gatherings if they must gather.

Western officials are also calling for vigilance, calling the situation "concerning."

In a statement, Jennifer Massey, associate vice-president of student experience at Western said, “We are at a critical stage in this pandemic, and following public health protocols remains as important as ever. Our community is counting on our students to remain vigilant in the fight against COVID-19.”

The health unit continues to recommend limiting interactions to only those who are part of your household, maintaining two metres physical distance, limiting unnecessary trips and wearing a mask as much as possible indoors or outdoors.