Lambton's medical officer of health is pointing to infection prevention and control practices to explain an alarming COVID-19 outbreak at Vision Nursing Home.
As of Thursday night the health unit was reporting a total of 38 confirmed cases and four deaths at the Wellington Street facility.
Dr. Sudit Ranade noted that the number of infected staff, at 18, almost equals the cases among residents.
"There are lots of ways to use personal protective equipment and different behaviours that you can use to stop the spread from person to person," said Ranade on CHOK (103.9 FM, 1070 AM) Friday. "I think it's important that people keep doing those things, remind themselves, remind each other and monitor that and how it's going."
He said attention has to be paid to all aspects of daily routines.
"Consider what's happening when people are not delivering care. If you're delivering care and then you're congregating with each other later, then that still defeats the purpose. A lot of it comes down to basic behaviours that we need to ingrain in our routine practice," he said.
Dr. Ranade said the numbers at Vision are not that surprising to him, noting that when an outbreak takes hold in a home it's expected it will get worse before it gets better.
Institutional outbreaks declared May 15 at Marshall Gowland Manor and at Village on the St. Clair have had no further cases reported this week, and no staff have been infected.
Dr. Ranade also said the recent recommendation from Canada's chief public health officer to wear masks in public has to be taken in context.
"So if you're in the middle of downtown Toronto, and you take the subway and you're surrounded by other people, even then the evidence is unclear but I can understand why they would say maybe a mask might be helpful. Where we live, the population density is much lower. You can probably effectively distance yourself from people, and for the few minutes that you can't in the store, the risk is not really meaningfully increased."
Lambton's top public health official said wearing a mask is not mandatory but if someone is afraid and wants to wear one, there's nothing wrong with that decision.
"I wouldn't want people who are wearing masks to get really down on people who are not wearing masks. It's your choice, you can follow it if you think that it's going to help, but we really don't think that it's going to make a meaningful difference here, based on just the population density."
There are 243 confirmed COVID cases in Sarnia-Lambton, 173 have recovered and 19 people have died.