Canterbury District Health Board says damp and unchanged personal protective equipment (PPE) was likely to blame for three of its healthcare workers getting Covid-19.
The staff tested positive for the virus last week, after caring for the coronavirus patients from Rosewood Rest Home and Hospital, and helping move some of them to Burwood Hospital in Christchurch.
Technical experts from the health board had been investigating how the staff became unwell, and today the health board said a "PPE breach" was the most likely scenario.
Chief Medical Officer Dr Sue Nightingale said on 6 April when the patients were transferred, some staff were unable to change PPE as frequently as recommended.
"It appears that due to the demands on staff, in particular on the day of resident transfer from Rosewood to Burwood and the day after, it was not always easy for them to interrupt care for very unwell dependant patients," she said.
"Some staff reported their PPE had become moist with the physical exertion that occurred over some hours that day. This factor is likely to have led to exposure to Covid-19."
At that time, RNZ understands staff only had access to paper masks, rather than the full-filter N95 masks. The health board moved to provide them with those masks, and visors more than a week later on 15 April.
The health board says staff caring for Rosewood residents now change their PPE at least every two hours, and a buddy system has been introduced to ensure they use PPE correctly.
But the Nurses Organisation said that should have happened sooner because staff had already been asking for better PPE by the time they moved patients to Burwood Hospital, citing shortages of supplies, and gowns that ripped.
Its kaiwhakahaere Kerri Nuku said it was unfair for the health board to effectively point the finger at employees.
"It's unfair to lay the blame on the nursing staff not changing regularly when there actually wasn't stock available, or quality stock to make them feel comfortable and be safe at work," she said.
"I appreciate that this is still under investigation but employers have an obligation under the Health and Safety at Work Act to ensure that all staff - when you're dealing with a situation needing PPE gear - are kept safe."
Nuku said PPE availability had improved across the country over the past four weeks, but it was important to ensure that "steady supply" continued.
"We need to make sure that we've got PPE to deal with Covid-19, should we have cluster outbreaks, but we also need to make sure that we've got supplies to cope with winter ailments."
Inadequate PPE supplies not a factor - DHB
Canterbury DHB incident Controller Dan Coward said staff had been supplied with adequate PPE throughout the pandemic and it was "most certainly not a factor" when the three Burwood Hospital workers picked up Covid-19.
"In fact, as a result of a staff member's request we made additional items available to some staff caring for residents with Covid-19 and this included N95 masks in addition to the standard surgical masks. We have also added visors to the PPE available as an alternative to goggles," he said.
"These aren't required in the ward for clinical reasons but were made available to provide alternative options for staff."
However, that was a concern for Mark Thomas, an associate professor at the University of Auckland School of Medical Sciences, and on the Auckland District Health Board.
He said health boards needed to be clear about what PPE was necessary to protect staff from Covid-19.
"When there is a genuine reason for someone to be wearing PPE, then they should be wearing the full kit that's required, not just part of it," he said.
"This sort of sloppiness of 'Oh yes, if you feel like it then you should use it', with regard to N95 masks, helps to weaken the message of what staff should be doing when they're at risk and when they're not at risk."
Canterbury DHB's PPE problems had also stirred up uncertainty elsewhere in the community.
Dorothy - who didn't want her last name used - said her mother, who is in a wing of Burwood Hospital separate from the Rosewood patients, was now having trouble trusting its ability to contain Covid-19.
"I just read the news article this morning and got a wee bit upset, because it's like they're saying the protective equipment that the nurses and staff are wearing aren't up to code. That's worrying, for someone who has a mum in hospital that's a very vulnerable person anyway."
The Nurses Organisation said it was watching health boards to ensure PPE supplies remained plentiful as the winter flu season approached.
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