Now that the cold weather has hit and people are moving inside, many doctors and scientists are urging Canadians not only to resist getting complacent about wearing masks to protect against COVID-19 — but also to take a closer look at whether that cloth mask is keeping you and others as safe as possible.

The World Health Organization is encouraging even the vaccinated to keep the masks on, particularly indoors, as the Delta variant of Covid-19 ricochets around the world.

World Health Organization (WHO) officials stressed Friday the need for fully vaccinated people to “continue to be appropriately cautious” and keep up with social distancing measures like mask wearing as the highly infectious Delta variant of the coronavirus becomes increasingly dominant in the U.S. and spurs new Covid-19 surges around the world—including in highly vaccinated countries.

A group of doctors and health-care providers are calling on public health organizations in Canada to acknowledge airborne spread of COVID-19 and adjust restrictions accordingly.

The same week that the Centers for Disease Control and Prevention relaxed mask recommendations for Americans fully vaccinated against COVID-19, a couple of high-profile cases of breakthrough infections among vaccinated people have raised some questions about whether it’s safe to remove masks indoors just yet.