The Simcoe Muskoka health unit reports 51 new COVID-19 cases since Friday.
Six people are hospitalized with the virus.
The health unit reports the first week of November as the highest weekly number of cases, with 141.
The numbers released Monday show 14 cases in New Tecumseth, 13 in Barrie, nine in Bradford and six in Essa Township. The remaining cases are in Tay, Wasaga Beach, Midland, Innisfil, and Clearview.
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Meantime, Ontario reports 1,242 new COVID-19 cases and a dozen virus-related deaths.
York Region remains among the province's hot spots, including Toronto, Peel Region and Ottawa.