Without the hundreds of thousands of worshippers it welcomes every May 13, the vast esplanade of Portugal's Catholic Fatima shrine was nearly empty for its annual celebration for the first time in its century-long history.

Closed to the public because of the new coronavirus pandemic, only about 30 employees attended the mass on Wednesday in the small town where three poor shepherd children reported visions of the Virgin Mary in 1917.

Last year, 6.3 million people visited the shrine, the country's most renowned pilgrimage site.

"It is possible that many people think this pilgrimage is sad because it is held on closed grounds without the large crowds and the colour of previous years," the local bishop Antonio Marto acknowledged from an altar mounted in the square, in a ceremony streamed online.

In a message read by Marto, Pope Francis -- who visited the shrine in 2017 -- also regretted that the "force of circumstance" had made the pilgrimage to Fatima impossible.

"Today it is only through heart and soul that we are able to make the connection with the Virgin Mary," the pope said. 

The town's shopkeepers and hoteliers counted their losses. 

In front of his small store, one of the few to have reopened after the country lifted a state of emergency last week, Manuel Moniz bitterly regretted the absence of tourists. 

"We don't see anyone and we don't sell anything. I've never seen anything like this," the 72-year-old said.

The closure of Portugal's borders and the paralysis of the tourism sector are having "a disastrous impact on the whole region," said Alexandre Marto, who runs a cooperative of around 10 hotels with 1,000 beds, out of a total of 9,000 in Fatima.

"This week alone, I estimate that we have lost around 45,000 overnight stays," he said, pointing out that foreign tourists account for more than 70 percent of the town's hotel guests.

After the mass, in front of the deserted shrine complex, a priest had another takeaway from the unusual circumstances surrounding the annual event.

"This solitude and this desolation offer a spiritual and human experience, which makes us understand that alone, we cannot enrich life," Francisco Pereira said.