WE were only a few weeks into 2019 when an issue that would come to dominate so many of this year's headlines first surfaced: infection deaths at Glasgow's flagship hospital.

On the evening of Friday January 18, NHS Greater Glasgow and Clyde issued a bombshell statement revealing that two patients treated at the Queen Elizabeth University Hospital had died in December 2018 after contracting a fungal infection linked to pigeon droppings.

It later emerged that both were cancer patients thought to have become infected after inhaling the Cryptococcus bacteria, though exactly how it came to be spread through the hospital's ventilation system remains a mystery.

Both deaths, of 73-year-old Gail Armstrong and a 10-year-old boy who has never been named, are still being investigated by the Crown Office.

Within days of the revelations, Health Secretary Jeane Freeman announced a review of the design, construction and maintenance of the QEUH and its adjacent Royal Hospital for Children (RHC), which both opened in 2015.

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It followed on from the closure of paediatric cancer wards 2A and 2B in September 2018 following a string of infections linked to taps, showers and drains. Tragically, the 10-year-old boy who contracted Cryptococcosis was only in the adult hospital because the children's unit had been closed for remedial work.

In February, a report by Health Protection Scotland revealed that testing had detected widespread microbial contamination of the facility's water supply before it opened, adding that the bugs appeared to have persisted at "higher than normally acceptable levels" in a number of areas despite extensive cleansing.

As 2019 wore on, alarm over potential safety issues at the complex escalated.

In August, it emerged that ward 6A of the QEUH - where paediatric cancer patients had been transferred - was closing to new admissions after three more patients contracted infections, two caused by rare bacteria.

In September, the Herald on Sunday revealed that independent consultants had raised concerns over ventilation back in 2015. Leaked reports detailed how experts from Innovated Design Solutions found that the ventilation strategy in ward 2A was "likely to promote the risks associated with uncontrolled ingress of infectious aerosols into patient areas".

Air handling units were the wrong size, and in the children's cancer ward the ventilation only achieved three air changes per hour - well below the 10 per hour required to minimise infection risk in patients with the most vulnerable immune systems.

The health board said defects had been or are now being rectified, including a £2 million upgrade of the ventilation in wards 2A and B.

Nonetheless, the revelations were a tipping point and two days after the Herald broke the story, Ms Freeman announced a public inquiry into both the QEUH campus and Edinburgh's crisis-hit children's hospital to explore how defects in ventilation and other key building systems occurred. Both facilities had been built by the same contractor, Brookfield Multiplex.

In November the scandal erupted again when it emerged that a retrospective clinician-led review had identified up to 26 cases of water supply infections among children treated in wards 2A and B in 2017 - in addition to the 23 already known of between January and September 2018 which triggered the unit's closure.

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Crucially, this included Milly Main, a 10-year-old leukaemia patient who died in August 2017 after suffering toxic shock when her Hickman line became contaminated with the bacteria Stenotrophomonas maltophilia.

The case raised questions about why the unit had not been closed sooner, and culminated in NHS GGC being placed in special measures.

In recent days the saga has taken a new twist as the health board revealed its plans to sue Brookfield Multiplex.

NHS Lothian has also faced its own struggles this year as excitement over the opening of the new Royal Hospital for Children and Young People (RHCYP) descended into chaos when a last-minute inspection in June revealed safety flaws in its critical care ventilation.

The facility was already two years behind its original July 2017 opening date, but on July 4 Ms Freeman announced that it would remain closed. It later emerged that she had overruled NHS Lothian's push for a partial opening.

In August, a report by Audit Scotland highlighted how bitterly relations had broken down between NHS Lothian and the private consortium building the hospital.

It detailed how health board bosses had first sought legal advice in September 2017 on suing IHSL Ltd - which comprised of Canadian-based Brookfield Multiplex as the contractor for construction - only to be told it was too risky.

NHS Lothian insisted that it had "identified a number of issues that it believed were non-compliant with the original contractual requirements", but in the end had decided to settle out of court.

In February this year, NHS Lothian signed a settlement agreement - approved by the Scottish Government - to pay IHSL an extra £11.6 million to resolve problems with drainage, heater batteries, and void fire detectors. On February 22 the facility was handed over to NHS Lothian, and the health board started paying the consortium £1.35m a month in service charges.

In September, Ms Freeman announced that the children’s hospital would not open until autumn 2020. The cost of the delay to taxpayers has been put at put at £16.05m - including £4m just to rectify the ventilation. The key problem was that the air changes in critical care and parts of paediatric oncology were wrongly set at four per hour, instead of the 10-per-hour requirement.

An independent review by KPMG traced the error back to a document produced by NHS Lothian and distributed to bidders during the project’s tender stage. KPMG said opportunities to spot the mistake were missed as far back as November 2016, but that the fiasco was characterised by confusion over who was ultimately responsible for verifying that the design and built met safety requirements.

A second report by NHS National Services Scotland (NSS), also published in September, identified a number of additional issues with theatre ventilation, a flooding risk to the basement kitchen, and no record that recommendations set out in a February 2019 Legionella risk assessment had been acted upon.

A follow-up report by NSS in October flagged up further glitches, including a requirement to upgrade fire doors and improve smoke dampers on evacuation routes as well as the potential for the hospital's critical life support equipment to fail in a power cut because it was reliant on a single electrical supply.

The most recent Audit Scotland report, published last week, concluded that many questions "remain unanswered". The public inquiry into what went wrong at both these hospitals must answer those questions - and provide the lessons to prevent it happening again.