AFRI-c v1.0
Research type
Research Study
Full title
Air Filtration to prevent symptomatic winter Respiratory Infections (including COVID-19) in care homes: the AFRI-c cluster randomised controlled trial with nested internal pilot, process and economic evaluations (AFRI-c)
IRAS ID
298022
Contact name
Alastair Hay
Contact email
Sponsor organisation
Univeristy of Bristol (UoB)
ISRCTN Number
ISRCTN63437172
Duration of Study in the UK
3 years, 5 months, 31 days
Research summary
Research Summary
Respiratory infections, such as COVID, coughs, colds and flu are more serious in older people. In care homes, infections can spread easily in shared spaces when people breathe in or swallow airborne droplets containing germs when others cough or sneeze.
This study aims to find out whether air filtration using portable high efficiency particulate air (HEPA) filters can reduce symptoms of respiratory infections in residents of older people’s care homes during the winter period. For years, these air filters have been built into hospital operating theatres and transplant wards to prevent infections. Although we know they trap airborne particles, no one has tested if they can improve human health.
Care homes will be divided into two groups at random, with one continuing with usual care AND receiving air filters, and the other continuing with usual care only. We are interested to see whether filters placed in communal and private rooms reduce infection symptoms, antibiotic use and number of falls as well as cost-effectiveness of the filters. We are also interested in the effect of the filters on staff sickness days away from work.
We will recruit from 74 care homes in England. The duration of recruitment will be over 3 winters (10 in pilot phase, 32 each winter thereafter). Care home staff will collect data about residents’ symptoms, and will recruit 10 residents per care home. These residents in the air filter group will consent to receive an air filter in their bedroom and access to their medical records. For the usual care group they will consent for their medical records to be accessed. We aim to include 834 residents who will be in the trial for up to 8 months each. The results of this trial will help understand whether or not filters can reduce the spread of infections.
Summary of Results
Expressions of interest were received from 243 care homes, of which 144 were considered eligible and 95 randomised. Four care homes subsequently withdrew leaving 91 care homes (44 intervention and 47 control), all of whom completed the study. They were similar with respect to architectural type, CQC rating, ownership, provision of dementia and nursing care, number of resident communal rooms, having an infection prevention and control policy and a policy for window opening/closing of doors.
In total 1,158 residents participated in the trial, 569 in intervention care homes (who received a HEPA filtration unit in their private bedroom) and 589 in control care homes, contributing 201,319 valid follow up days to the primary analysis. The HEPA filter units were used at the maximum settings and numbers tolerated by the residents and staff.
Intervention and control group residents were similar with respect to sex, age, self-reported ethnicity, receiving nursing care, dementia, median Rockwood frailty score, receiving influenza and COVID-19 vaccinations, and communal room visiting frequency.
Intervention arm residents experienced 390 respiratory infection episodes during 95,235 at risk days (0.99 infections per resident per winter), while control arm residents experienced 442 respiratory infection episodes in 102,579 days (1.04 infections per resident per winter). There was no evidence of a difference in respiratory infection episodes between intervention and control groups.
There was also no evidence of a difference between the groups in: the number of symptomatic respiratory infections; number of episodes or symptomatic gastrointestinal infections, urinary infections, episodes of fever and/or delirium; antibiotics; falls/near falls; the number of hospitalisations; number of microbiologically confirmed infections; or reported care home temperature, odours and air quality.
Compliance in the intervention group was very high, and completion of daily data recording was similarly very high.
Anonymised daily symptom data were provided for 1,985 residents, 1,004 in intervention care homes (exposed to communal room HEPA filters) and 932 in control care homes, contributing 258,286 follow up days. The residents in the intervention and control groups were similar with respect to age, dementia, Rockwood frailty score, and receiving influenza or COVID-19 vaccination.
There was also no evidence that using HEPA filtration units in communal rooms made any difference to the number of respiratory infection episodes, symptomatic respiratory infection days, gastrointestinal infections (episodes or symptomatic days), episodes of fever and/or delirium, or falls/near falls.
There was no evidence that using HEPA filtration units affected the number of staff working days lost to illness or infections or the number of microbiologically confirmed care home infection outbreaks.REC name
London - Harrow Research Ethics Committee
REC reference
21/HRA/4318
Date of REC Opinion
24 Nov 2021
REC opinion
Further Information Favourable Opinion