Highlights
- There are very few field studies comparing the level of Legionella colonisation in buildings before and after the pandemic lockdowns.
- This study analysed a group of hotels that experienced prolonged closures in 2020 due to the COVID-19 pandemic.
- Legionella spp. were analysed by standard culture, immediately after reopening, from the domestic water distribution systems of 73 hotels that experienced closures (from 1 to >4 months) during 2020.
- The results were compared with those obtained in similar samples from 2019.
- The results suggest that hotels that had the longest prolonged closures (> 3 months) may have had a higher risk of exposure to Legionella spp.
- The authors suggest that the findings highlight the importance of adequate preopening cleaning and disinfection procedures for hotel water systems, and choosing the most effective disinfection methods, especially for hot water systems after prolonged closure periods.