The longest international border in the world, between Canada and the US, will remain closed until January 2021 due to the Covid-19 pandemic, Canada’s Prime Minister Justin Trudeau has announced.

“Canada and the US agreed to keep our shared border closed until January 21,” Trudeau said in a news conference. The border was initially closed in March to slow the spread of the novel coronavirus. The closure has been renewed monthly since then. Only trade in goods and merchandise and essential travel are allowed.

A second wave of Covid-19 infections in Canada, with a total of nearly 450,000 cases reported as of Friday last week, has forced several regions to reintroduce pandemic measures.

The US is the worst-affected country in the world, with almost 300,000 deaths from 15.7 million cases. The border between the US and Mexico will also remain shut until the same date, said Chad Wolf, the acting head of the Department of Homeland Security.

“In order to continue to prevent the spread of COVID, the US, Mexico and Canada will extend the restrictions on non-essential travel through January 2021. We are working closely with Mexico and Canada to keep essential trade & travel open while also protecting our citizens from the virus,” he said.