As of 12:01 a.m. Monday, Sarnia-Lambton will be elevated to the yellow "protect" level in the province's COVID-19 response framework.
The change from the "green" level means no more than six people can be seated together at restaurants and bars, alcohol sales in casinos will be further restricted, and contact tracing increased.
There are also additional requirements surrounding meeting and event spaces, retail stores, cinemas and performing arts facilities.
Lambton Public Health said the strengthened measures include the potential for enhanced targeted enforcement, fines, and increased education to limit further transmission.
Lambton Medical Officer of Health Dr. Sudit Ranade said part of the reason for the change is due to the fact that we reached 12.2 cases of COVID-19 per 100,000 people during the week of November 15-21.
"That puts us into the range that moves into the 'protect' level," said Ranade. "Also, the per cent positivity of tests has been creeping up as well, and that went up to about 0.56 per cent. Remember that those two numbers are not the only factors in decision-making, it's slightly more comprehensive than just two indicators. There might be times when those indicators change but the level stays the same, or the indicators don't change but the level changes because of other reasons."
Dr. Ranade said residents need to be cautious no matter what level the county is in.
"Regardless of the status level, the decisions we need to make to live with COVID-19 and reduce our own personal risk are the same," he said. "Continue to minimize our non-essential social interactions and treat every situation like COVID-19 is present."
Dr. Ranade is reminding everyone that increasing the frequency and duration of non-essential social interactions places everyone at greater risk of COVID-19 transmission.
As of Monday, Windsor-Essex is moving to the red "control" level, while Chatham-Kent and London-Middlesex remain at yellow.
Sarnia-Lambton was the only region in southwestern Ontario still at the green "standard measures" level.