Brussels - With Belgian leaders still debating how to set-up and deploy a coronavirus tracing smartphone app, authorities have set up old-fashioned call centres to interview the infected.

At phonebanks like those at N-Allo -- a private Brussels firm contracted under the government scheme -- dozens of new hires reach out to those tested positive for COVID-19.

A country of 11.5 million people, Belgium has suffered of the highest per capita rates of the novel coronavirus during the world epidemic and seen more than 9,000 deaths since it spread to Europe.

But the rate of new cases is now falling and the country has begun cautiously to emerge from a strict lockdown, with schools and some businesses resuming work under social distancing measures designed to prevent the eruption of a feared second wave.

Belgium’s new profession, the Virus Tracker

Whether or not this is successful depends in large measure on efforts to track down sufferers and to trace their contacts, to clamp down on new virus clusters before they spread back into the relatively dense and urban national population.

Call centres like that run by N-Allo, and volunteers like 65-year-old Pierre Fournier, are an important part of this.

"I wanted to be a small cog in the machine to track and eradicate the pandemic, to help the cause," he told AFP, as he worked among a group of around 60 COVID trackers, some of the hundreds who came forward when Belgium's three regional governments called.

Pierre is a consultant for car park firms. Here he works alongside a job-seeking criminologist. Others in the room are call centre veterans, hired on temporary contracts and paid at market rates, according to N-Allo.

Their task is a more delicate one than pitching loft insulation or car insurance.

The people they call are those who have contracted the virus and been tested positive in Belgium's hard-pressed health system.

Now, working with them by telephone, the callers attempt to establish who the patients spent time with -- and may have infected -- during the two days before the moment of their first symptoms and the seven days after that.

If these encounters lasted longer than 15 minutes and took place less than 1.5 metres (just under five feet) apart, then the second person -- usually a relative, friend or colleague -- is declared a "person at high risk".

Another tracker will then have to find them and warn them to place themselves in voluntary quarantine for two weeks.

"The goal is to reduce the circles of contamination so that bit by bit we smother them and can go further in easing the lockdown," says Gladys Villeys of healthcare provider Mutualite Partenamut, which helps runs this second stage.

If, after 24 hours, the call centres have not been able to contact the at risk parties by telephone, then social workers, paramedics or ambulance crews are dispatched to their homes.

"In that case, we send in the professionals, who are used to dealing with patients and often speak several languages. That makes things easier," she says.

Brussels is houses the European Union's main headquarters and is a long-time international trade and migration hub, home to people of 185 nationalities.

Of 340 such home visits conducted since the operation began on May 11, fewer than a third of potential carriers have refused to cooperate or, as Villeys, says: "A minority, luckily."

"A lot of people are frightened to share their personal information. We try to reassure them that it will remain only in our hands," she says.

Not just on the doorstep, but in the call centre too, the trackers have to proceed gently, often finding themselves in contact with frightened or confused patients.

It helps when a family doctor has already warned them that the tracers will be calling.

"Then they've usually already drawn up a list of their contacts, there's no initial surprise," says Fournier.

But, so far, the scheme has been a kind of dry run for a potentially more complicated task. Patients who were more or less observing Belgium's two-month-old lockdown often have a short list of two or three at risk contacts.

How to test, track and trace COVID-19 infections, according to an OECD report

As the country's "deconfinement" progresses, however, Belgians are once again encountering colleagues, eating in each others' homes in small groups and chancing upon acquaintances in parks and on public transport.

Even if bars, restaurants and mass gatherings such as football matches or music festivals are still closed, "gradually the number of contacts are going to go up" warns Xavier Brenez, director of another health insurer, Mutualites Libres.

Genuine privacy concerns and traditional Belgian political wrangling have delayed the launch of a tracking app that could help identify more fleeting public encounters but, when it comes, Brenez hopes it will work in parallel with the telephone trackers.

By Matthieu Demeestere