COVID-19 variants of concern have been identified in an outbreak at a public school in Alvinston, health officials say.
The outbreak at Brooke Central Public School was declared Wednesday after six people tested positive for COVID-19.
Lambton Public Health said Thursday that two of those cases screened positive for a COVID-19 variant of concern.
The school is being shut down for two weeks, with students switching to online learning.
"We regret the disruption this may cause families," Dr. Sudit Ranade, the region's medical officer of health, said in a media release.
"We are working closely with school staff to contact everyone who may have been in close contact with the confirmed cases and are providing guidance to the Lambton Kent District School Board to support the continued implementation of [infection prevention and control] measures to help manage the school outbreak and reduce the risk of further COVID-19 transmission in the school community."
In total, nine cases of variants of concern have been discovered in Lambton County, one relating to someone who does not live in the region.
Three other cases are connected, and the investigation is ongoing for the remaining five cases.
The health unit hasn't said which of the known variants have been found locally.
New mutations of the virus that causes COVID-19 have been reported in the U.K., Brazil and South Africa. The variants are considered more transmissible and have sparked concern that they could fuel a third wave of the virus in Ontario.
On Thursday, Lambton Public Health reported 28 new cases of the virus, bringing the active total to 152.
There are eight outbreaks active, including the one at Brooke Central Public School and two other schools.
Since the pandemic began, 46 people in Sarnia-Lambton have died after testing positive for COVID-19.