The device smells chemicals in infected individuals, opening the door to large-scale testing across the world.

Scientists say it could be used at airports, offices, factories, and even football, rugby, and cricket grounds.

Project leader Professor Noam Sobel explained: "The e-nose generates a pattern in every odour—it characterizes the smell of Covid-19."

Rapid diagnosis is key to bringing the pandemic under control, said Sobel. It will enable people to attend mass gatherings and travel, as well as return to school or work.

The instrument, called Pen3, has been trained to identify VOCs (volatile organic compounds) in the inner nasal passage, rather than in the breath.

Experiments on 503 people—27 of whom were later deemed to have COVID-19—found it was up to 94 percent accurate.

They were recruited at a drive-thru testing station Tel Aviv, organized by Israel's Red Cross.