A pregnant mother who worked in the United Kingdom as a nurse has described her horror at learning she had contracted COVID-19 while quarantining at a Perth hotel.

Alison Rose arrived in Western Australia with her partner and four-year-old daughter on April 3 and was quarantining at the Mercure Hotel when she and her child tested positive on day 12.

Ms Rose said it was a “real shock” to learn through genome sequencing that they had contracted the virus from a couple who had returned from India and were staying in an opposite room.

“It has been upsetting, but it is what it is … we’ve just got to get on with it really,” she told ABC radio.

“I just can’t wait to get out now.”

As a nurse, Ms Rose had administered COVID-19 vaccines in the UK but said she had been careful to protect herself.

“I self-isolated for three weeks before we left the UK … pulled our daughter from school just to make sure – we were really careful,” she said.

Ms Rose, who is six months pregnant and has asthma, said she had been worried about her unborn child but had been reassured after doctors checked her oxygen levels.

She is expected to finish her quarantine period in about one week.

Authorities are investigating how the spread happened, but Premier Mark McGowan has conceded the Mercure is “not one of the best” hotels for quarantining and would no longer be used for returned travellers.

Instead, the facility will be used for low-risk seasonal workers from Tonga and Vanuatu.

An independent review of the quarantine system following January’s five-day lockdown, which was sparked by a security guard contracting the virus, examined airflow and ventilation.

It found the Mercure Hotel was the least safe facility.