An outbreak has been declared after 22 people who took part in gatherings last week tested positive for COVID-19, the Middlesex-London Health Unit (MLHU) said Thursday.

The health unit said it was made aware of at least 10 different post-secondary student gatherings that were held in homes between March 2 and March 6. The MLHU said all 22 cases were linked to these social gatherings.

Western University has also released a statement noting that some of its students were involved in the community outbreak.

While most of the 22 students involved in the outbreak live off campus, the school said three students who live on campus were moved outside of residence to isolate.

"This situation is very concerning," said Jennifer Massey, associate vice-president of student experience at Western. "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."

Meanwhile, investigators are continuing to trace close contacts of those who have tested positive to determine the number of individuals at risk.

The region recorded 29 new positive cases of COVID-19 on Thursday, the highest single-day count since mid-February.

"Now is not the time to open up our home to those who aren't part of our household and it certainly is not the time to start attending parties. COVID-19 is still here and we could very easily slide back to seeing widespread transmission in the community," said Dr. Alex Summers, Associate Medical Officer of Health with the MLHU.

"The end of the pandemic may be in sight now that we've started vaccinations, but it doesn't mean that we can let our guard down and stop doing all the things that have helped slow the spread of COVID-19."