Coronavirus: NHS retirees on the frontline
When the coronavirus pandemic hit the UK, many retired healthcare professionals returned to the frontline.
But what drives someone to put their retirement on hold and head straight for potential danger?
BBC News NI spoke to four women who answered the call.
From a midwife in County Fermanagh, to a nurse selected to be in charge of the UK's first - and largest - Nightingale hospital in London, all four willingly entered an unknown and worrying situation when the pandemic began.
It was a text from a former colleague that convinced Deirdre Barr, from Londonderry, to return to work.
Not that she needed much convincing.
The message was straightforward: "Any chance you would come out of retirement and be my operations director in an NHS field hospital?
"My response was a photograph with me doing a thumbs up sign," Ms Barr told BBC News NI.
"There was no decision to make. I trained as a nurse to make a difference and this was the ultimate opportunity to do this."
As director of operations at the Nightingale Hospital in London, Ms Barr worked with a range of people from architects and builders to clinicians, to get the hospital up and running as quickly as possible.
The temporary NHS Nightingale Hospital, at east London's ExCel centre, was designed to hold as many as 4,000 patients and was the first of several such facilities across the UK. It was built in just nine days.
"The build phase was exciting, exhausting and emotional as we were all putting in long hours, living in hotels to get the facility ready to support the population of London," said Ms Barr, who lives in Beckenham in Kent.
"There were times when the scale and size of what we were building made it emotional and scary but we had a mission to achieve so were all focused on this task."
In 2014, after 39 years in the NHS, Ms Barr took early retirement and worked in management consultancy.
Last year she was awarded the Order of St John, in recognition of her contribution to St John Ambulance.
She said returning to work "was a bit like riding a bike".
"It was an amazing experience, everyone had a 'can do' attitude," she said.
"We did not have time to find out about other members of the team's previous roles, so it was a flat hierarchy.
"We all worked together as was needed. It was all hands on deck to get the job done."
For Catriona Campbell, the return to work was a simple case of "once a nurse, always a nurse - so offering clinical support comes naturally".
Mrs Campbell, from south Armagh, retired in March 2018 after 39 years of nursing. During that time she spent 29 years with the occupational health team, becoming a manager in 2007.
But after enjoying "the slower pace of life" - gardening, spending time with family and walking in the countryside with her husband John - she came back to help with administering flu vaccinations in the winter.
Shortly afterwards, coronavirus struck and she decided it was time to return to the Southern Trust in March to help out once again.
"I am fit and healthy and was available to help, so I knew that I could contribute to the efforts of our brilliant occupational health team," she told BBC News NI.
Mrs Campbell has been running the occupational health helpline, along with some other colleagues who have been redeployed.
She admitted it took a bit of time to get back up to speed with things.
"Although it has been very busy, I have really enjoyed being part of the team again and playing my part in the response against Covid-19," she said.
Labour in lockdown
Ann O'Reilly's retirement lasted just five months before she returned to work as a midwife on the labour ward at the South West Acute Hospital in Enniskillen, County Fermanagh.
After 38 years in midwifery - the last 10 years of which were spent as a sister on the maternity ward - she said the opportunity to provide "professional, safe care with kindness" to women in childbirth "is a unique privilege".
She said it has been challenging at times and the impact of coronavirus is felt by staff, as well as patients and their families.
For Barbara Dunn, it had been almost 30 years since she worked as a nurse on a hospital ward.
She had moved into nursing improvement and was a manager in the South Eastern Trust before retiring last year.
"I thought 'I'll be able to do something'," she told BBC News NI.
"It was a bit of a learning curve to say the least but it has been an absolute privilege."
She took on a three-month contract as a nurse on Ward 11 in Lagan Valley Hospital, where older people with mental health conditions are treated.
"You don't forget the basics, like being patient-centred, empathetic and caring, or the professional values of nursing - and the camaraderie never changes.
"But when you're a namby-pamby, nine-to-five sort of girl for 30 years you soon forget how hard the people on the wards work during their 13-hour shifts, especially in the heat while wearing PPE."