Hundreds of people queued as mass testing began in Merthyr Tydfil, set up to try and curb the spread of Covid.
Up to 60,000 people could be tested in total, with those without symptoms urged to take a test.
It prompted concerns some could be left hard up if told to self-isolate weeks before Christmas.
Shirley Jones, 82 whose partner died just 24 hours earlier while awaiting cancer treatment delayed due to the pandemic, was the first to be tested.
She said: “I could’ve stayed in this morning and not come because I was grieving, but I knew I had to do the right thing in coming up here for myself for our community.
“And I pray to God that everybody comes up and has a test like I have.”
Ms Jones said her partner, Desmond Rogers, 83, who died at the town’s Prince Charles Hospital, had bowel cancer which spread to his stomach and throat.
“I couldn’t say goodbye to him,” she told the PA news agency.
Anyone living or working in the county can now get a test, in a bid to curb the spread of the virus and queues have formed at the town’s testing centre.
On Saturday Merthyr council also revealed
Merthyr council has created a regional helpline for those who test positive or were contacted by tracers and told to self-isolate.
The Welsh Government has set up a payment scheme for those on low wages.
Council leader Kevin O’Neill confirmed about 60,000 people could be tested.
“We want that response today of people coming along who are not symptomatic,” he said.
“We can seek out the disease where we don’t know where it is, where people haven’t got the symptoms,” he told BBC Radio Wales.
“This is all about getting something in place that will work for the rest of the country.”
At the scene – BBC Wales reporter Lottie Morley
There’s a queue around the block outside the Merthyr Tydfil Leisure Centre this morning – it’s the first mass-Covid testing centre in Wales, opening weeks after the area was given the title of the worst affected place in the whole of the UK.
The cases in Merthyr Tydfil have reduced considerably, but people here are keen to get tested even if they have no symptoms.
Eileen Nelson, who has lived in Merthyr her whole life, said she would be getting a test because it was “essential” and “everybody should take advantage of it”.
At a first glance, it looks like it’s going to be a busy first day for the test centre.
At the start of November, the county had the highest rate of coronavirus in the UK. While the case rate has fallen dramatically in recent weeks, it remains among the worst hit areas in Wales.
Latest figures published on Saturday showed Merthyr Tydfil had 250.3 cases per 100,000 of the population in a seven-day period, behind Blaenau Gwent (396.5) and Neath Port Talbot (258.9).
Now the county has become the first part of Wales to pilot mass testing of asymptomatic people.
Anyone working, living or studying in the area has been urged to get tested for the virus, including children over the age of 11.
Up to 175 armed forces personnel have been drafted in to help with the testing, with the first site opening at Merthyr Tydfil Leisure Centre.
But there are fears that many will not take the voluntary test because a positive result would mean isolating just weeks before Christmas and potentially losing income.
‘We will pull through’
Merthyr Valley Homes, which supports people living in 4,100 homes across the county and employs 200 staff, said it was trying to encourage tenants and staff to take up the offer of testing.
Director Michelle Reid said: “We have been rehousing people escaping domestic violence and those who are at risk of being homeless, and we wouldn’t let anything get in the way of doing that.”
Ms Reid said the company was looking at how to support vulnerable and elderly residents, to help them access tests, and had been supporting people already struggling with rent and bills during the pandemic.
“I am very optimistic, the way people in Merthyr have come together to support each other has been incredible, we will pull through this,” she added.
People on low incomes who are told to self-isolate and are unable to work from home will be able to claim £500.
‘No one wants their children to go without’
At Twyn Community Hub, volunteers are getting ready to help prevent families and those living alone going hungry if forced to self-isolate.
During the pandemic the community rallied to help deliver over 270 food boxes a week, and more than 200 hot meals a week were cooked and delivered to households.
Project manager Louise Goodman said there were real fears in the community that people on zero-hour contracts or self-employed would go without pay before the Christmas holidays if told to self-isolate and that the county was being used as a “guinea pig”.
She said: “We are expecting lots of people to contact us for help. It has got to be done, and it will do good, but you must not forget that people’s lives are entwined with this.
“No one wants their children to go without, especially after such a horrible year.”
Despite concerns for people’s mental health and more people feeling isolated and going hungry, Ms Goodman said more people had been volunteering to help during lockdown.
“Everybody is amazing, it just shows what sort of community we are, everyone helps each other and pulls together,” she said.
Lessons from Liverpool
A similar pilot scheme in Liverpool started two weeks ago. By Friday, more than 140,000 people had been tested for coronavirus, with more than 700 testing positive.
“Those people… would have been unaware of the fact that they we’re both infected and infectious,” Liverpool City councillor Paul Brant told Politics Wales.
Col Sion Walker, from the Joint Military Command in Wales, said “lessons learned” from mass testing in Liverpool had been used to “try and make our system more effective… and get people through far quicker”.
He said testing was expected to take up to four weeks at up to 14 sites.
How will Merthyr’s testing work?
Merthyr Tydfil Council said everyone living, working or studying in the county should have two tests over 14 days, or three tests over a three-week period. People can request more if needed.
There is no booking system and people can just turn up at a testing centre.
Mass testing uses lateral flow tests which intend to produce a result within 20-30 minutes.
If an individual tests positive, they will be asked to immediately self-isolate at home and to take another test.
Pupils aged 11-18 who attend schools in Merthyr Tydfil or Merthyr Tydfil College will be able to have a test at their school or college, with parents asked to consent. Some large employers will also carry out testing.
Further sites are due to open in the coming weeks while home tests are being considered for the most vulnerable. Some sites are to stay open until 23 December.
What have the cases been like?
There were 458 cases in Merthyr Tydfil in the week up to 1 November and the case rate rose as high as 759 cases per 100,000.
The proportion of positive results was also high – accounting for nearly a third of people tested.
Those case rates have since come down and Merthyr Tydfil has been overtaken by Blaenau Gwent and Neath Port Talbot.