It’s a Sin writer Russell T Davies has warned “the fight is not over” when it comes to eradicating HIV.

He said misinformation about the virus made him “despair” and warned that we must not “blunder into the future without looking back at the past”.

Davies’ warnings come as UNAIDS, the UN’s joint aids prevention programme, warned the global response to HIV has suffered its most significant setback in decades due to cuts in global funding.

It warned a failure to reach the 2030 global HIV targets could result in an additional 3.3 million new HIV infections in the next five years.

The World Health Organisation regards HIV as a “major global public health issue” and estimated it had claimed 44.1 million lives to date.

While it isn’t curable, antiviral medication developed in the ’90s means that patients can live long and healthy lives.

Davies, 62, recalled a time when fear around the virus was front and centre of public consciousness, as deaths dominated the headlines.

“I was 18 in 1981, so I kind of witnessed and stood back from and was horrified by the epidemic that ensued,” said the Swansea-born screenwriter.

He said he while he remembered “the heroes who stood up and made it count, and have fought”, he was worried and angered by the misinformation and stigma that he believed still existed.

“There are great dangers coming. Now we have HIV denial, which is a growing force… that’s becoming almost policy in some places,” referring to a notion he said was spreading online in the United States that HIV does not cause Aids.

He added: “I’m absolutely certain the battle is not over and sometimes I fear that the battle’s about to begin again.”

It’s a Sin told the story of a young group of friends in London at the height of the Aids epidemic.

Davies, who is gay, is considered a trailblazer within LGBTQIA+ drama and said it was “the great privilege” of his life to have written a show that allowed people to talk about a virus that was, for so long, shrouded in shame.

“There is not a single day when someone doesn’t stop me and say how much that show meant to them,” he said.

Human immunodeficiency virus (HIV) is a virus that weakens your immune system and increases your risk of serious illness, according to the NHS.

It is most often spread by having vaginal, anal or oral sex with someone who has HIV, while not using a condom.

Aids (acquired immune deficiency syndrome), or late-stage HIV, is the name for a collection of serious illnesses caused by the HIV virus.

With the correct treatment, most people with HIV do not develop Aids and are able to live a long and healthy life.

There are approximately 2, 800 people living with HIV in Wales, according to Fast Track Cymru, a charity which aims to end HIV transmission in Wales.

There is a globally recognised target to end new transmissions of the virus by 2030.

Mark Lewis, a senior policy advisor to the All Party Parliamentary Group on HIV/Aids in Westminster, recalled the moment he learned he had the virus.

“I was sort of living a lie because I was working in the field, I was telling other people, I was keeping a list, but I hadn’t told my own family,” said the 43-year-old, originally from Carmarthenshire.

“I wasn’t worried about HIV because I thought it had gone away, because it wasn’t in the news as much, and I thought I was an educated person myself.”

Mr Lewis said he had experienced prejudice as a result of his diagnosis in 2018, including a dentist who asked him if it was safe for the clinic to treat him.

He also recalled an encounter with a barman who was gay, who didn’t know what World Aids Day was or recognise a pin worn by Mr Lewis which read “Can’t Pass It On” – a reference to the fact you can’t transmit HIV if you’re having effective treatment.

“That is the problem, a lot of youngsters don’t know about it, because we’ve come so far in the treatment and the prevention and all that,” he said.

“We’ve still got a long way to go.”

Dr Olwen Williams remembers learning about the first cases of HIV being reported in the UK in 1980s, when she was finishing her medical degree in Liverpool.

She remembers being unable to find any information about the condition in her textbooks.

As a young doctor originally from north Wales, she then spent time working on a HIV ward in London at the height of the epidemic.

“It was quite emotional because this was my peer group I was looking after and seeing,” said the now 66-year-old.

“They were people in their 20s and 30s. It was just devastating what was happening.”

Dr Williams reflected on the joy she felt as a doctor to be able to tell people they could live with HIV, thanks to modern medicine.

“It’s so phenomenal to be able to say in my lifetime, I have seen something going from being incurable, a life sentence, to actually something that is a chronic disease.”