Omicron COVID-19 variant confirmed in London region: MLHU

A day after a cluster of COVID-19 cases "highly likely" linked to the Omicron variant were reported, one case with the new variant has been confirmed, according to the Middlesex-London Health Unit (MLHU).

The health unit was informed Tuesday afternoon that whole genome sequencing of the sample was completed and confirms that Omicron has arrived in Middlesex-London.

On Monday, the MLHU reported that based on travel history and screening positive for a specific marker associated with Omicron, there was a "strong probability" that the variant had arrived in the region.

The two cases were linked to travellers who arrived in London from Nigeria in late November.

There are now 40 cases connected to the cluster, which officials say involves 171 high-risk close contacts.

MLHU Acting Medical Officer of Health Dr. Alex Summers said despite not having additional test results they are treating all cases in the cluster as linked to Omicron.

“The chances that the other cases associated with this cluster are Omicron are essentially 100 per cent. In my view, there may be one or two cases that are coincidentally linked here but are actually caused by the Delta variant. However, given our investigation to date, we are treating all cases associated with this cluster as though they are a result of the Omicron burial variant.“

So far a number of locations from day cares to a church have been associated with the cluster or potential close contacts including:

• God's Favourite House church (14 cases)
• Princess Elizabeth Public School (one case)
• Delaware Public School (two cases)
• St. Marguerite d'Youville Catholic Elementary School (five cases)
• St. Nicholas Catholic Elementary School (three cases)
• St. Mary Choir and Orchestra Catholic School (two cases)

The three Catholic schools have closed for the week due to the large number of staff and students required to self-isolate as a result of being possible close contacts.

One major difference from previous outbreaks is that with Omicron even fully-vaccinated close contacts are being asked to quarantine to minimize the risk of transmission. With previous variants they would need to get tested but not self-isolate.

The health unit says it is continuing to follow up with persons under investigation for the variant and close contacts of confirmed cases.

Summers says the key now is "...we must continue as a community to make sure that we're doing everything we can to reduce our risk of COVID transmission as we head into the holiday season, which means getting vaccinated, wearing your mask, making sure that mask fits and reducing your social contacts through this holiday season."

Additional confirmations of the variant in other connected cases are expected in the coming days.

- With files from CTV News London's Marek Sutherland