Air Filtration to reduce Respiratory Infections (including COVID-19) in care homes: the AFRI-c cluster randomised controlled trial with nested internal pilot, process and economic evaluations

Respiratory infections, such as COVID, coughs, colds and 'flu (influenza) are common in all age groups, but elderly people in care homes are more vulnerable because they are frail, have multiple health conditions and infections are easily spread within the shared space. As COVID has shown, respiratory infections in care home residents are also more serious, with many requiring hospital care and many not recovering. Less severe infections still require antibiotics, contributing to antibiotic resistance - itself considered a public health crisis. Respiratory infections are mainly spread when people breathe in or swallow airborne droplets containing germs. These are produced when others cough or sneeze. Care homes are required to follow the NHS 'Code of Practice on Infection, Prevention and Control (IPC)', but this focuses on preventing infections spread directly from contaminated hands or bodily fluids, and indirectly through germs settling on furniture or medical equipment. There are currently 220,000 people over 65 years living in UK care homes. This number is predicted to double by 2040, and as highlighted by the devastating effects of COVID in care homes, reducing the spread of infections in care homes is a research priority. Air filtration seems an obvious solution since high efficiency particulate air (HEPA) filters can quickly remove germs from the air. For years, they have been built into hospital operating theatres and transplant wards to prevent infections. But their use has not been tested in standard hospital wards or in care homes before. Now that HEPA filters are built into portable units available for domestic use, they can be placed in these locations with relative ease. We talked to residents, carers and staff at three care homes about the practicalities of putting air filters in communal areas and residents' rooms. Residents told us getting old and staying healthy is a priority, that AFRI-c is a 'no brainer' and that air filters would need to be installed carefully to minimise the risk of falls. Staff liked that air filters would add to existing IPC measures without disrupting the 'flow of care'. One air filter (made by PhilipsTM) was preferred because it was sturdier, had a night-time quiet mode, and a visible indicator of air cleanliness. Post-COVID, staff told us we should run the study remotely, with telephone and video support from the study team. They told us they feel confident this would be possible as they are now using Zoom and other online systems for many routine tasks. After care homes agree to place air filters in communal areas for one winter (September to April), up to 10 residents will be consented to have an air filter in their room, and to work with staff to report the number of infections they experience for the same period. We will divide the care homes into two groups at random (so they are similar), with one group receiving the air filters, and the other continuing with usual care. The study team will support all aspects of the study, without physically visiting the homes. Our experience suggests about 1 in 3 care homes and 1 in 3 residents will want to help. We will allow sufficient time to talk to relatives and friends of residents who do not have capacity (e.g. people with dementia) so they can take part. Our design also takes account of the 40% of residents expected to drop out of the study through moving away, illness or death.