An investigation in the Pullman Hotel Covid-19 outbreak in Auckland is looking at whether airborne particles generated by bowel movements could have been a factor.
A Ministry of Health report into the Pullman Hotel outbreak last month has made several recommendations but admits the cause of spread amongst guests may never be known.
Ventilation has long been one of the suspected spreaders of the virus between hotel guests.
The report said because airborne viruses can be generated by bowel movements, it wants to check the hotel's bathroom exhaust fans meet Building Code fresh air standards.
Ventilation in the lifts also remains a concern, the report said.
It revealed the Ministry of Business Invovation and Employment said the hotel, which was closed for investigation, had to be opened again by 15 February because it was needed for returnees with MIQ vouchers.