Ms Orla Hegarty:

We do not have records on the air quality in any of these buildings at any given time. All we can do is look at the patterns of spread, the speed of spread and the fact some buildings are much more highly impacted than others. They are all clues that this virus is airborne and has lingered in the air. I have also looked pretty closely at some of the other nursing home outbreaks in the Netherlands and especially in Canada and the same patterns are there of very rapid spread.

The conditions in nursing homes are quite particular and this is the reason we have had the problem. They tend to be underventilated because people are looking to keep warm. The operators are largely private and they look to save money on energy. Nursing homes are often in converted or subdivided buildings that maybe, when they were changed, ventilation was not considered properly or vents were blocked up. The people who are there are more vulnerable.

The climate makes a considerable impact. I did not get into it today but the spread of the initial phase of the pandemic was in very particular climate conditions across North America, Europe, Iran, Wuhan and Japan where the air temperature was between 5° and 11° Celsius outside with low absolute humidity. There was a very strong pattern to that. In those particular climate conditions, which would be typical of Ireland in heating season, if you bring that air indoors and heat it to 20° for comfort, it is incredibly dry, and dry low humidity air is connected also with a higher risk of Covid in indoor air conditions. So you have a perfect storm of overheated buildings, underventilated very dry air, people who are most susceptible and certain buildings. Unlike in homes where people have showers and there is cooking, which puts moisture in the air, that does not happen in nursing homes. There is a low occupancy and those activities are not happening close to patients, so you probably had people whose noses and throats dried out, and mucus is a person's first protection against this. For a whole series of reasons it is quite explainable what happened in nursing homes. More and more evidence shows, to my mind and certainly from speaking to people working in lots of different disciplines ranging from medicine to physics and chemistry, there is an alignment that plausibly explains why the areas were at risk and, more importantly, how we can prevent it happening again.