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STUDY PROTOCOL
Determining the clinical and
cost-effectiveness of nasal sprays and a
physical activity and stress management
intervention to reduce respiratory tract
infections in primary care: A protocol for the
‘Immune Defence’ randomised controlled trial
Jane VennikID
1
*, Adam W. A. Geraghty
1
, Kate MartinsonID
1
, Lucy Yardley
2,3
,
Beth Stuart
1,4
, Michael Moore
1
, Nick Francis
1
, Alastair Hay
5
, Theo Verheij
6
,
Katherine Bradbury
2
, Kate Greenwell
2
, Laura Dennison
2
, Sian Williamson
2
,
James Denison-Day
2
, Ben Ainsworth
2
, James Raftery
1
, Shihua Zhu
1
, Christopher Butler
6
,
Samantha Richards-HallID
7
, Paul Little
1
1Primary Care Research Centre, University of Southampton, Southampton, United Kingdom, 2School of
Psychology, University of Southampton, Southampton, United Kingdom, 3School of Psychological Science,
University of Bristol, Bristol, United Kingdom, 4Pragmatic Clinical Trials Unit, Queen Mary University of
London, London, United Kingdom, 5Centre for Academic Primary Care, Bristol Medical School, Population
Health Sciences, University of Bristol, Bristol, United Kingdom, 6Julius Center for Health Sciences and
Primary Care, University Medical Center Utrecht, Utrecht, Netherlands, 7Nuffield Department of Primary
Care Health Sciences, University of Oxford, Oxford, United Kingdom
*j.vennik@soton.ac.uk
Abstract
Background
Most adults in the UK experience at least one viral respiratory tract infection (RTI) per year.
Individuals with comorbidities and those with recurrent RTIs are at higher risk of infections.
This can lead to more severe illness, worse quality of life and more days off work. There is
promising evidence that using common nasal sprays or improving immune function through
increasing physical activity and managing stress, may reduce the incidence and severity of
RTIs.
Methods and design
Immune Defence is an open, parallel group, randomised controlled trial. Up to 15000 adults
from UK general practices, with a comorbidity or risk factor for infection and/or recurrent
infections (3 or more infections per year) will be randomly allocated to i) a gel-based nasal
spray designed to inhibit viral respiratory infections; ii) a saline nasal spray, iii) a digital inter-
vention promoting physical activity and stress management, or iv) usual care with brief
advice for managing infections, for 12 months. Participants will complete monthly question-
naires online. The primary outcome is the total number of days of illness due to RTIs over 6
months. Key secondary outcomes include: days with symptoms moderately bad or worse;
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OPEN ACCESS
Citation: Vennik J, Geraghty AWA, Martinson K,
Yardley L, Stuart B, Moore M, et al. (2023)
Determining the clinical and cost-effectiveness of
nasal sprays and a physical activity and stress
management intervention to reduce respiratory
tract infections in primary care: A protocol for the
‘Immune Defence’ randomised controlled trial.
PLoS ONE 18(7): e0285693. https://doi.org/
10.1371/journal.pone.0285693
Editor: Johannes Stortz, GERMANY
Received: April 17, 2023
Accepted: April 26, 2023
Published: July 14, 2023
Peer Review History: PLOS recognizes the
benefits of transparency in the peer review
process; therefore, we enable the publication of
all of the content of peer review and author
responses alongside final, published articles. The
editorial history of this article is available here:
https://doi.org/10.1371/journal.pone.0285693
Copyright: ©2023 Vennik et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: No datasets were
generated or analysed during the current study. All
days where work/normal activities were impaired; incidence of RTI; incidence of COVID-19;
health service contacts; antibiotic usage; beliefs about antibiotics; intention to consult; num-
ber of days of illness in total due to respiratory tract infections over 12 months. Economic
evaluation from an NHS perspective will compare the interventions, expressed as incremen-
tal cost effectiveness ratios. A nested mixed methods process evaluation will examine
uptake and engagement with the interventions and trial procedures.
Trial status
Recruitment commenced in December 2020 and the last participant is expected to complete
the trial in April 2024.
Discussion
Common nasal sprays and digital interventions to promote physical activity and stress man-
agement are low cost, accessible interventions applicable to primary care. If effective, they
have the potential to reduce the individual and societal impact of RTIs.
Trial registration
Prospectively registered with ISRCTN registry (17936080) on 30/10/2020.
Sponsor
This RCT is sponsored by University of Southampton. The sponsors had no role in the study
design, decision to publish, or preparation of the manuscript.
1 Introduction
1.1 Background and rationale
Most adults in the UK experience at least one viral respiratory tract infection (RTI) per year
[1]. Whilst symptoms are often self-limiting, they can significantly affect health-related quality
of life and are the most common reason for sickness absence [2]. The majority of patients
attending their GP with RTIs are prescribed antibiotics [3,4] and primary care antibiotic use
is strongly related to the threat of antibiotic resistance [5]. Individuals with comorbidities and/
or recurrent infections are a higher initial priority: they have more days of illness, more severe
illness, worse quality of life and higher work absence [6–8]. Low cost, non-prescription inter-
ventions to reduce severity and duration of illness associated with RTIs are needed to reduce
burden on healthcare services and antibiotic usage.
Reducing illness through modification of the nasal environment. Antiviral nasal sprays
are commonly available to purchase over-the-counter in the UK. As medical devices, they
have the potential to change the nasal environment, by creating a physical barrier to viral pene-
tration or reducing viral replication [9]. Trials of antiviral nasal sprays compared to saline sug-
gest there may be benefit in reduction of days of symptoms when used early in the illness, but
the trial evidence is rather limited [10,11]. Saline may also have a role in reducing symptoms
associated with RTIs by irrigating the nasal passages and reducing levels of virus in the naso-
pharynx [9]. A systematic review of saline nasal irrigation (nasal rinses and sprays) in acute
upper RTIs found some benefit in symptom control, although trials were small with a high risk
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relevant data from this study will be made available
upon study completion
Funding: This protocol is funded by NIHR
Programme Grants for Applied Research (RP-PG-
0218-20005) and PL is the grant holder. The
funders did not and will not have a role in study
design, data collection and analysis, decision to
publish, or preparation of the manuscript.
Competing interests: The authors have declared
that no competing interests exist
of bias [12]. Whilst saline nasal sprays may have some effect in managing RTIs, they make for
a useful comparison for the antiviral nasal spray as they have an equivalent method of delivery.
Reducing illness through improving immune function. Physical activity and stress man-
agement both improve immune function and have empirical evidence of benefit in reducing
illness episodes. A Cochrane review [13] of the effect of physical activity on reducing illness
episodes suggests promising effects for recurrence and symptom days, although most were
small trials of generally low quality. One high quality small US trial documented a reduction in
illness of more than 3 days [14] and these results are supported by a more recent trial [15].
There are similar estimates from a cohort study among 1002 adults [16]. Reasons for low
uptake and adherence to exercise in patients with chronic illnesses is multi-faceted [17], so
simple generic advice is unlikely to work.
Perceived stress [18], negative emotion [19], and poor social support [20] predict subse-
quent illness, viral shedding, cytokine activity, as well as adverse mucosal defence and pathoge-
nicity [21,22]. Mindfulness can reduce stress and negative emotions [23]. A small US trial of
an 8 week course documented a reduction of 3–4 illness days compared with controls [14] and
the most recent trial [15] by the same group showed a reduction of 1 day. However, the US tri-
als involved either intensive supervised exercise (8 sessions) or similarly intensive supervised
mindfulness courses (again 8 sessions), each session being at least 2.5 hours. For behavioural
and psychological support to be viable care offerings for those with RTIs in primary care,
accessible and scalable delivery methods are necessary. Research has found that digital inter-
ventions which support physical activity can improve exercise outcomes for people with
chronic health conditions, especially if underpinned by behavioural change theory [24]. Simi-
larly, digital interventions supporting stress management have shown benefit in a range of
health conditions [25,26] and are implementable in the primary care setting. As yet, none
have been developed and evaluated for managing RTIs.
In the present trial, we sought to determine the clinical and cost effectiveness of differing,
low-cost approaches to supporting those with RTIs in primary care; nasal spray interventions
and digital interventions promoting physical activity and stress, compared to usual care with
brief advice for managing RTIs.
1.2 Objectives
1.2.1 Primary objective
The primary objective is to assess the effectiveness and cost-effectiveness of a gel-based nasal
spray, a saline nasal spray, and a physical activity and stress management intervention, in
reducing the duration of illness days due to RTIs among at-risk individuals when compared to
usual care with brief advice about managing RTIs at 6 months.
1.2.2 Secondary objective
The secondary objectives are:
• To evaluate the incidence of all RTIs, incidence of COVID-like infections, days with symp-
toms moderately bad or worse; days where work/normal activities were impaired; contact
with health service; hospital admissions; antibiotic usage; beliefs about antibiotics; and inten-
tion to consult, over 6 and 12 months
• To evaluate patient engagement with the interventions by exploring patients’ experiences of
the different interventions to understand why different patients did or didn’t engage with
the treatment/intervention, and what might affect future engagement.
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1.3 Trial design
Immune Defence is an open, randomised, parallel group, 4-arm trial evaluating i) a gel-based
nasal spray, ii) a saline nasal spray, iii) a physical activity and stress management intervention
and iv) usual care plus brief advice, in reducing duration and severity of RTIs in UK primary
care, over 6 and 12 months. We will assess the impact overall and in at-risk subgroups of
patients defined by whether they have a) recurrent infections, no risk factors; b) risk factors,
no recurrent infections; or c) risk factors plus recurrent infections.
A nested mixed methods process evaluation will triangulate qualitative interview data with
quantitative attitudinal and behavioural process measures and quantitative intervention usage
data.
2 Materials and methods
The protocol was prospectively registered with ISRCTN registry (17936080) on 30/10/2020
and is reported according to the SPIRIT guidelines (S1 Appendix). The trial schedule is
reported in Fig 1.
For further information about trial registration, see Table 1.
2.1 Trial setting
Participants will be identified through UK primary care. GP practices will be engaged through
the NIHR Clinical Research Networks, and selected from regions of urban and rural settings,
large and small practices, and high and low deprivation.
2.2 Eligibility criteria
Participants will be eligible for the trial if they are 18 years and above, with a serious comorbid-
ity or a risk factor for infection and normally experience one or more RTIs per year: Immuno-
suppression due to a serious illness or medication (e.g. chemotherapy); heart disease; asthma
or lung disease; diabetes; mild hepatic impairment; stroke or other severe neurological condi-
tion; obesity (BMI>30); aged >65; 3 or more RTIs in the last year.
Participants will be excluded if they have any of the following identified through practice
records: a terminal illness or are receiving palliative care; have a diagnosis of dementia; live in
residential care; have pituitary adenoma. Participants will also be excluded through participant
self-report if they: are pregnant/breast-feeding; regularly use nasal sprays to prevent respira-
tory infections; are allergic to nasal sprays; live in the same household as another participant;
have been previously involved in the development phase of the trial.
2.3 Interventions
2.3.1 Active treatment arms. Participants in the three active treatment arms will have
access to a digital intervention (website available via desktop and smart devices) which has
been developed using evidence-, theory- and person-based approaches [27]. Each intervention
aims to facilitate behaviour change through three key mechanisms: (1) promotion of positive
outcome expectancies (beliefs that the behaviour will prevent RTIs); (2) improved self-efficacy
for performing the behaviour (mainly through clear instructions on how to perform the behav-
iour and advice on overcoming behavioural barriers); and (3) reduction of behavioural con-
cerns (e.g. safety). The interventions include persuasive information about how each
individual intervention may help reduce the number, duration and severity of RTIs
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experienced, clear instructions about how to perform the target intervention behaviour, and
information to address key concerns that participants may have about engaging in the behav-
iour. Intervention-specific behaviour change techniques are discussed below.
Fig 1. Schedule of enrolment, interventions, and assessments.
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Nasal sprays
The two nasal sprays in the trial are available to purchase over-the-counter in pharmacies
and supermarkets in the UK and are registered as medical devices: a gel-based nasal spray and
a saline nasal spray. Full details of the nasal spray constituents will be presented when the find-
ings are published, to preserve masking during the trial period.
The digital interventions supporting use of the nasal sprays will provide explanations and
instructions on how to use the spray, including a demonstration video. Concerns about using
the sprays will be addressed, and tips to help people to remember to use and to adopt the cor-
rect technique are included. This information is duplicated in a paper booklet that will be sent
to participants together with 2 bottles of nasal spray after randomisation (further bottles will
Table 1. Items from the World Health organisation trial registration data set.
Data category Information
Primary registry and trial
identifying number
ISRCTN17936080
Date of registration 30/10/2020
Secondary identifying numbers -
Source of monetary or material
support
NIHR-Programme Grants for Applied Research (PGfAR) (NIHR) (UK)
Primary sponsor University of Southampton, rgoinfo@soton.ac.uk
Secondary sponsor (s) -
Contact for public queries Dr Jane Vennik, j.vennik@soton.ac.uk
Contact for scientific queries Dr Jane Vennik, j.vennik@soton.ac.uk
Public title Evaluating nasal sprays and physical activity/stress management in reducing
respiratory infections in primary care
Scientific title Reducing respiratory infections in primary care: the Immune Defence Study
Countries of recruitment England, United Kingdom
Health condition or problem
studied
Respiratory
Interventions 1. Gel-based nasal spray (medical device)
2. Saline nasal spray (medical device)
3. Support for physical activity and stress management (behavioural
intervention)
4. Usual care for infections
Key inclusion and exclusion
criteria
Inclusion criteria: 18+ years with a serious comorbidity or a risk factor for
infection: Immunosuppression due to a serious illness or medication (e.g.
chemotherapy); heart disease; asthma or lung disease; diabetes; mild hepatic
impairment; stroke or other severe neurological condition; obesity (BMI>30);
aged >65; 3 or more RTIs in the last year
Exclusion criteria: a terminal illness/palliative care; dementia; residential care;
pituitary adenoma; pregnant/breast-feeding; regularly use nasal sprays to
prevent respiratory infections; are allergic to nasal sprays; live in the same
household as another participant; involved in the development phase of the trial.
Study type Randomised controlled trial
Date of first enrolment 12/12/2020
Target sample size Up to 15000
Recruitment status Recruiting
Primary outcomes Total number of days of illness due to respiratory tract infections over 6 months.
Key secondary outcomes Days with symptoms moderately bad or worse; days where work/normal
activities were impaired; incidence of RTI; incidence of COVID-19; health
service contacts; antibiotic usage; beliefs about antibiotics; intention to consult;
number of days of illness in total due to respiratory tract infections over 12
months
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be available on request). The digital intervention to support nasal spray use and its develop-
ment is described in more detail elsewhere [28].
Participants will be instructed to use the nasal spray in three ways during the trial:
i. At first signs of an infection: Up to 6 times daily (2 sprays in each nostril) until symptom-
free for 2 days.
ii. After potential exposure to infection (e.g. using public transport, supermarkets, cafes/
pubs): 2 sprays in each nostril immediately after exposures, 1 hour later and last thing at
night.
iii. After prolonged exposure (e.g. close contact with/living with someone who has an infec-
tion): Up to 6 times daily (2 sprays in each nostril) until the close contact has recovered.
Digital intervention promoting physical activity and stress management
The digital intervention promoting physical activity and stress management includes a brief
introductory section with content on the impact of RTIs and how physical activity and stress
management can prevent RTIs, followed by two previously developed online modules to sup-
port physical activity (Getting Active) and stress management (Healthy Paths through Stress).
The ‘Getting Active’ was developed as part of a digital intervention to improve overall quality
of life among cancer survivors [29,30] and has now been optimised for people at risk of RTIs.
‘Getting active’ aims to build motivation for physical activity by promoting the benefits and
addressing concerns, increasing self-efficacy by providing advice on safe physical activity and
overcoming barriers, and facilitating behavioural regulation through goal setting, goal review
(automated tailored feedback and support), action planning and self-monitoring (using pedom-
eters to count and record steps). Getting Active sends automated emails encouraging and sup-
porting participants to engage with the intervention and overcome barriers to physical activity.
As well as the addition of the introductory section, the intervention was adapted for people at
risk of RTIs by including physical activity benefits and addressing concerns relevant to this tar-
get group. A pedometer will be sent out by post to each participant at the recruitment stage.
“Healthy Paths through Stress” was initially developed as a digital intervention for stress/
emotional distress for patients in primary care [31]. It has also been used to manage distress in
cancer survivors [29]. Participants can explore a range of evidence-based techniques and read
rationales and instructions for trying them. The techniques in the intervention are drawn from
behavioural activation (pleasant activity scheduling, sleep hygiene) and/or mindfulness-based
approaches (e.g. 3-minute breathing space, self-compassion exercise). Participants can select
those they find most helpful. Participants are advised that the techniques can be helpful at any
time but are particularly useful when experiencing challenging life events.
Participants are encouraged to try both interventions and will have access to them at all
times throughout the trial. These are complex interventions which could plausibly generate
additive effects of the individual components.
2.3.2 Comparator: Usual care with brief advice about managing infections. Participants
allocated to usual care will receive a brief page of advice about managing respiratory tract
infections, based upon NHS current advice (rest, keeping warm, fluids, over-the-counter med-
ications for symptom relief). Specific resource use will be tracked for health economic analysis.
The usual care group will be asked not to use any over-the-counter nasal sprays during the
trial period. After 12 months, participants will be offered access to the digital intervention pro-
moting physical activity and stress management for a short time.
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2.4 Outcome measures
2.4.1 Primary outcome. The primary outcome will be the total number of days of illness
due to respiratory tract infections over 6 months.
2.4.2 Key secondary outcomes. Key secondary outcomes include: days with symptoms
moderately bad or worse; days where work/normal activities were impaired; incidence of RTI;
incidence of COVID-19; health service contacts; antibiotic usage; beliefs about antibiotics;
intention to consult over 6 and 12 months; number of days of illness in total due to respiratory
tract infections over 12 months
2.4.3 Other secondary outcomes. Other secondary outcome measures will be as follows:
• Physical activity will be evaluated using International Physical Activity questionnaire [32]
sitting behaviours questionnaire [33] and activity monitors.
• Mental health will be assessed using the Perceived Stress Scale [34], PHQ-8 [35] and GAD-7
[36]
• Participant quality of life will be determined using EQ-5d-5L [37]
• Resource use: NHS contacts will be collected through participant self-report and by retro-
spective notes review. Out-of-pocket spending will be collected through participant self-
report RTI related medication collected through retrospective notes review.
• Side effects of the nasal sprays will be collected through participant self-report
• Serious adverse events will be collected through participant self-report and reports from the
GP surgery.
• Adherence to nasal sprays, getting active and healthy paths assessed through participant self-
report.
•RTI avoidance behaviours/Vitamin D supplementation assessed through participant self-
report.
2.5 Participants
Participant flow chart is presented in Fig 2. Recruitment commenced in December 2020 and is
expected to complete by April 2023.
2.5.1 Participant identification. Participants will be invited through targeted invitation
by the GP practice. Practices will use executable files to identify eligible participants from the
clinical record system. Lists of patients will be generated as follows:
Search A: Aged 18+ years plus a serious comorbidity/risk factor for infection (all seasons)
Search B: Aged 65+ years, no comorbidities/‘at risk due to COVID’ (season 1 only)
Search C: Aged 18+ years plus an antibiotic prescription for RTI in the previous year to iden-
tify those most likely to be at risk of recurrent RTIs (all seasons)
Search D: Aged 18–65 years, no comorbidities/risk factors–a wide sample to identify younger
participants who may self-report recurrent infections (season 3 only)
Lists will be checked by the practice to ensure suitability to receive an invitation. A random
sample of participants (up to 3000 letters or 6000 texts per practice depending on practice list
size) will be sent an invitation pack by either i) a secure mail service (Docmail) containing an
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invitation letter, participant information sheet, details about how to sign up, and a sign-up
code to facilitate stratification by health status, or ii) a brief text message invitation with links
to receive an invitation pack by email.
Fig 2. Participant flow chart.
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2.5.2 Informed consent and screening. Interested participants will visit the Immune
Defence website and sign up using their unique sign-up code. Participants will give their con-
sent online prior to completing the screening questions to check for exclusion criteria not
identified by the practice searches (pregnant/breast-feeding; regularly use nasal sprays to pre-
vent infections; allergy to nasal sprays; living in the same household as another participant; previ-
ously involved in the development phase of the trial). Ineligible patients will be provided with a
link to a brief advice page about managing RTIs. Patients who meet the screening criteria will
complete baseline measures and proceed to randomisation.
2.5.3 Randomisation. The randomisation process (1:1:1:1) for this trial will be fully auto-
mated. The Immune Defence website software will generate a randomisation sequence and
computer algorithm to block randomise participants to the 4 trial groups. As randomisation is
automated, the sequence will be concealed from the trial team. Patients will be stratified on the
basis of whether they are in a higher risk group (over 65 and/or having comorbid condition)
and whether or not they have recurrent RTIs (�3 in the last year) to three strata: stratum 1
(recurrence, no risk factors); stratum 2 (risk factors, no recurrence); stratum 3 (risk factors
plus recurrence).
2.5.4 Blinding/masking. Full blinding of trial participants to their intervention group is
not possible. However, to reduce possible contamination (as the nasal sprays are available to
purchase over-the-counter in pharmacies and supermarkets) the nasal sprays will be masked
to their content by removing the manufacturers labels, and adding generic trial labels. As the
nasal sprays in the study are medical devices there should not be a need to unmask them dur-
ing the study. The GP practices are aware of the contents and other medical professionals
involved in the care of participants can contact the study team for the same information if
required. Staff responsible for data entry and data analysis will be blind to the treatment group.
2.6 Sample size
Our primary outcome is the number of days of illness in total due to RTIs at 6 months.
Provisional sample size calculation agreed with the funder following the start of the
COVID pandemic:
To detect a 1-day difference among individuals having an infection (hazard ratio 1.2) for
alpha of 0.01 and 90% power, we estimated we would require 147 individuals per group, and
allowing for at least 15% of individuals to contract an infection during a 6-month winter/
spring period 980 individuals per group. With four groups and 80% follow-up, then 4900 indi-
viduals would be needed. We also aim to estimate outcomes in the three strata (stratum 1 –
recurrence, no risk factors; stratum 2—risk factors, no recurrence; stratum 3—risk factors plus
recurrence) so planned to recruit 14,700 participants in total. We accepted that this would pro-
vide less power for our key secondary outcome (incidence of infections). However, the aim for
the latter outcome is to compare each intervention with control, so using the arguments of
Cook and Farewell, since each analysis of intervention versus control is independent, this
should not require a conservative Bonferroni correction [28], and we can use an alpha of 0.05.
Using these assumptions, the above sample size would provide more than 80% power to esti-
mate a 25% reduction in the incidence of infections from 20% to 15% in each stratum and
more than 90% power if the incidence of infections is 15% using all strata combined. We will
update the sample size calculations based on the observed rates of infections in each season
when the SAP is drafted.
Revised estimates for the primary outcome based on data of the incidence of infections
from the first two seasons (2020/21; 2021/22):
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1. Stratum 1 (recurrence, no risk factors): Currently, in this group about 71%, compared to
our original assumption of 15%, had an infection. Basing our recalculation on the more
conservative lower limit of the 95% confidence interval of this estimate, we might assume
that at least 65% of this group get an infection. Based on the original number per group of
147 (i.e. changing no other assumptions), we’d need 226 per group, and for 4 groups and
with 80% follow up 1130. For 80% power, based on the original assumptions, we would
require 111 per group. If 65% get an infection, then we would need 111/0.65 = 171 per
group. For 4 groups with 80% follow up we would require 855 participants.
2. Stratum 2 (risk factors, no recurrence): In this group, the observed infection rate has been
around 40% compared to our assumption of 15%. On this basis, based on the original sam-
ple size calculation of 147 per group, we would require 147/0.40 = 368 per group. With 4
groups and 80% follow up this gives a total of 1472 for 90% power. For 80% power, we
would require 1388 participants.
3. Stratum 3 (risk factors plus recurrence): The infection rate is currently around 62% and fol-
low up is just under 80%. On the basis of the original calculation, assuming at least 60%
having an infection, we would need 245 per group, time 4 groups with 80% follow up gives
1225.
Revised estimates for the number of infections (secondary outcome):
1. In stratum 1 (recurrence, no risk factors): Assuming an infection rate of 65% and for 15%
absolute reduction to 50% we require 227 complete cases in each group for 90% power
(1135 with four groups and 80% follow up) and 170 for 80% power (850 in total)
2. In stratum 2 (risk factors, no recurrence): To detect a change from 40% to 30% we estimate
we need 476 compete cases in each group for 90% power (2380 with four group and 80%
follow-up) and 356 for 80% power (1780 in total).
3. In stratum 3 (risk factors plus recurrence): To detect a change from 60% to 45% for 90%
power we need 231 complete cases in each group or 1155 for four groups and 80% follow-
up.
2.7 Data collection and management
2.7.1 Data collection
Data will be collected online at baseline, and then monthly for 13 months (52 weeks) using the
trial and intervention website. Each month participants will receive an automated email and 1
week reminder to complete brief questionnaires, with more detailed questions at 6 months
and 13 months. Non-completers at 6 months and 13 months will also be sent a paper question-
naire after 2 weeks and at 6 months (primary outcome) will also be followed up by telephone
for limited responses after 3–4 weeks. Willing participants will complete an optional daily
paper-based symptom diary should they develop an RTI during the trial period.
All data will be managed in accordance with the General Data Protection Regulation
(GDPR) 2018. Electronic data will be stored on secure servers at University of Southampton
and password protected. Anonymised paper questionnaires and diaries will be stored in locked
filing cabinets prior to data entry and destroyed at the end of the study. Personal data will be
collected for the purposes of study participation and kept separately from the questionnaire
data for 10 years after the study has completed. Anonymous study questionnaires will be
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deposited in a secure data archive and made available for secondary data analysis, subject to
further ethical approvals.
2.7.2 Data analysis
A detailed statistical analysis plan will be developed prior to data analysis. IBM1SPSS1soft-
ware platform, Stata and Excel software will be used to evaluate outcomes.
The primary analysis will be based on those who report at least one infection in a normal
year (before COVID). We will also conduct a sensitivity analysis to include all participants
who included under the broader inclusion criteria (‘at-risk’ due to COVID).
The primary time point for analysis will be at 6 months. The analysis of the primary out-
come and other continuous outcomes will compare all groups. For the incidence of infection
data the primary analysis will be between each intervention group and usual care, and if any of
these demonstrate an intervention is effective then we propose secondary comparisons
between groups. A secondary analysis will use repeated measures over the year.
The particular regression models used will depend on the data and the patterns of residuals
but we anticipate logistic regression models for dichotomous outcomes, negative binomial
models for count data, and generalised linear mixed models will be used for continuous vari-
ables (all controlling for baseline values; stratification variables and potential confounding var-
iables). Intention to Treat (ITT) analysis with missing data imputed (via chained-equations
multiple imputation model) will be the primary analysis, and complete cases as a sensitivity
analysis. Secondary analyses will follow a similar modelling approach to the primary analyses.
The repeated measures analysis over the one-year period will allow for the clustering of obser-
vations within participants over time. Estimates will be provided for key subgroups (e.g. those
with recurrent infections (>3/year), age >65, the presence and number of serious comorbidi-
ties). Results will be reported in line with the CONSORT guidelines.
2.8 Economic evaluation
The economic analysis will take a NHS perspective covering the intervention costs, NHS and
personal social service (PSS). The impact on cost effectiveness of out-of-pocket spending and
employment will be assessed. Data will be collected by patient monthly report, supplemented
by a brief case notes review for non-responders, and a detailed notes review on 5–10% of par-
ticipants to check precision of self-reported data. Quality of Life (QOL) will be measured by
EQ-5D-5L at baseline, 3 months 6 months and 12 months. QALYs will be estimated by means
of area under the curve. The differences for Cost and QALYs between interventions will be
estimated adjusted for baseline characteristics. Where appropriate we will estimate incremen-
tal cost-effectiveness ratios (ICERs) for comparing different interventions. Bootstrapping will
generate incremental cost effectiveness ratios (ICERs). Cost-effectiveness acceptability curves
will be produced to reflect the probability of an intervention being cost-effective at different
willingness-to-pay values per QALY gained. Major assumptions made in the analysis will be
tested by means of sensitivity analyses.
2.9 Process evaluation
We will conduct a mixed-methods process evaluation to examine uptake and engagement
with the trial interventions and trial procedures and explore potential mechanisms of action
and contextual factors that may influence intervention delivery and outcomes.
Qualitative: A purposive sample of up to 100 patient participants (final numbers to be
determined considering information power [38]) will be invited to take part in a semi-struc-
tured telephone interview at least 3 months after randomisation each year/phase of the trial.
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The sample will include participants from each of the four intervention arms; and a range of
ages, genders, ethnicities, deprivation level, education, risk factors for infections, history of
RTIs, self-reported beliefs about RTIs, self-reported behaviour (physical activity, stress man-
agement, nasal spray use), and intervention usage. An interview topic guide was developed to
explore participants’ experiences of the intervention and the trial processes and procedures,
identify barriers and enablers to intervention engagement, perceived benefits of the interven-
tion, impact of the COVID-19 pandemic on their preventative behaviours and intervention
use. Interviews will be transcribed verbatim and transcripts will be managed using NVivo
qualitative data management software and analysed using reflexive thematic analysis [39]. We
will examine how and why our qualitative findings converge with, complement, or contradict
the quantitative findings.
Quantitative: Analysis of the process questionnaire data and usage data will assess inter-
vention reach (uptake; sample characteristics), self-reported adherence to the nasal sprays and
getting active and healthy paths interventions, predictors of adherence and outcomes (age;
gender; education; comorbidities; RTI and behavioural beliefs; barriers to behaviour change.
We will examine the moderator effects of baseline characteristics (particularly demographics)
on intervention engagement and outcomes, and the factors likely to mediate engagement (e.g.
behaviour, beliefs). We will also employ multi-level modelling to investigate how process mea-
sures relate to outcomes and intervention engagement.
2.10 Patient and public involvement
Two public contributors with experience and understanding of respiratory issues contributed
to the overall design of the study and are full collaborators on the programme grant.
Three public contributors assisted during the development of the digital interventions used
in this trial. This included taking part in think-aloud interviews, working through sections of
the interventions with a researcher. This helped to refine the interview topic guides and ensure
the language and communication was more broadly appropriate. Two contributors also
reviewed and commented on early drafts of the intervention pages and automated emails, and
reviewed the nasal spray instruction videos and written materials.
During development of the trial processes and materials, the public contributors piloted the
baseline and outcome questionnaires to ensure feasibility and clarity, and have reviewed all
participant-facing documentation.
Three public contributors are full members of the Trial Stakeholder group. They will attend
monthly stakeholder meetings and contribute to management decisions regarding develop-
ment and operationalising the trial. They will also contribute to the writing up of trial outputs
including publications and lay summaries.
2.11 Monitoring
2.11.1 Data monitoring and oversight
An independent trial steering committee (TSC) will be convened to provide trial oversight.
The TSC will also provide the function of the Data Monitoring and Ethics Committee
(DMEC) as the interventions and the trial processes are considered low risk.
Monthly management meetings with key stakeholders including co-investigators, collabo-
rators, trial management and public contributors will be held throughout the trial period.
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2.11.2 Adverse event reporting
Any adverse events reported by participants or by the GP surgery will be documented and
reviewed for severity, expectedness and relatedness to the trial and trial interventions. Serious
adverse events (SAEs) will be reviewed for expectedness. The trial includes elderly and high-
risk patients so a high rate of planned or emergency hospitalisations, new illness diagnoses,
worsening of pre-existing conditions, cardiovascular events, falls, and deaths are expected in
this population. These events will be documented and reviewed by the chief investigator. All
SAEs including serious adverse device effects (SADEs) that are unexpected or considered pos-
sibly,probably or definitely related to the trial or interventions, will be reported to the sponsor
and the REC immediately and followed up with a detailed written report.
2.11.3 Discontinuation and withdrawal of participants
If a participant expresses a wish to withdraw from the trial treatment (e.g. does not wish to use
the nasal sprays or advice from the Getting Active/Healthy Paths website), the trial team will
explain the importance of follow-up and ask if they would be willing to continue in the trial
without using the interventions and complete the questionnaires. This will be recorded in the
participants records. If the participant does not confirm continuation or requests full with-
drawal, the participant will be withdrawn from the trial and receive no further communication
from the trial team. All data collected up to the point of withdrawal will be used, unless the par-
ticipant has specifically requested for it to be deleted.
If a participant moves to a new GP practice, the trial team will endeavour to contact the
new practice and ask if they would notify the team of any SAEs during the trial period.
2.12 Ethics and dissemination
2.12.1 Research ethics approval
This trial was approved by the South East Scotland Research Ethics Committee 01 (20/SS/
0102) on 23
rd
October 2020 and the HRA on 29
th
October 2020.
2.12.2 Consent
All participants will receive information and will have the opportunity to ask questions prior
to deciding whether to take part. For the main trial, participants will give consent online after
registering on the Immune Defence website. For participants taking part in a telephone inter-
view, written consent or verbal consent over the telephone will be given by the participant to
the researcher.
2.12.3 Dissemination
The results of the trial will be disseminated in peer-reviewed journals and presented at primary
care conferences. All participants (GP practices and patient participants) will be sent an acces-
sible copy of the findings by email within 6 months of trial completion (unless they have opted
out of further contact). We will also disseminate our findings to the wider public via our
patient collaborators, PPI panels and through social media.
Findings will report anonymised data and summary statistics. No information identifying
individual participants or GP practices will be reported. Trial records will be retained for a
minimum of 10 years after the trial has been published.
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3 Discussion
RTIs generate symptoms which are the major driver of winter consultation pressures. Most
are viral in aetiology, so limiting viral replication and load through use of nasal sprays, could
reduce symptom burden and healthcare consultations, providing an evidence-based alterna-
tive to antibiotics. Similarly, if an intervention to promote physical activity and stress manage-
ment can be shown to reduce the number and severity of infections this will provide
significant motivator for those who suffer with recurrent infections to use the intervention.
Providing patients with alternative strategies to antibiotics is likely to modify patient beliefs
and expectation, reduce antibiotic use, and alter subsequent help seeking behaviour [6,7,32,
33]. This is also likely to be relevant during pandemic winters. SARS-CoV-2 is transmitted in
similar ways to other respiratory viruses, thus nasal sprays that reduce viral load have the
potential to reduce COVID-19 as well as usual winter illnesses. The brief physical activity and
stress management intervention is likely to be as pertinent during the pandemic winters, par-
ticularly as levels of anxiety and stress will be higher, and maintaining a good level of physical
activity has been strongly encouraged.
The trial has been designed to assess the impact in groups of individuals who are at high
risk for infections/adverse outcomes. These include individuals who report frequent recurrent
infections but with no significant comorbidities; individuals with serious comorbidities/risk
factors alone; and those with both recurrent infections and comorbidities/risk factors. Thus, it
is plausible that either an intervention to use a web-based applications to modify stress and
increase physical activity, or alternatively advice to use an inexpensive and easily available
nasal spray, could both help symptom control, de-medicalise infections, and be widely imple-
mented among the broad group of patients suffering recurrent infections.
3.1 Status and timeline
This trial is funded as part of the NIHR PGfAR RECUR Programme. The development and
optimisation of the trial platform was nearing completion in March 2020 and we had planned
a large feasibility trial in the 2020–21 winter season followed by a full trial in the following
2021–2023 seasons. However, with our experiences of conducting similar large trials together
with support from the funder, we felt able do a very much larger full trial starting in the 2020–
2021 winter season. This allows us to provide information not only about whether such inter-
ventions are likely to work in a pandemic season but also in more ‘normal’ winters for respira-
tory illnesses.
Recruitment of participants commenced in December 2020 and is expected to be com-
pleted by April 2023. The last participant will complete the trial by end April 2024. The current
version of the protocol is v8.1 dated 15-11-2022.
There have been two main amendments to the trial in response to the changing landscape
of the COVID pandemic. In season 1 we included participants aged 65+ considered higher
risk of COVID-19. From Season 2 onwards we tightened the inclusion criteria to include 65
+ who also reported at least 1 RTI in a normal year (before COVID). We considered this
would give a better chance of participants engaging with our interventions. In season 3 we are
focussing recruitment on participants with comorbidity/risk factors, and not recruiting any
further participants aged 65+ without any other risk factors for infection.
Supporting information
S1 Appendix. SPIRIT checklist.
(DOC)
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S1 File.
(PDF)
Author Contributions
Conceptualization: Adam W. A. Geraghty, Lucy Yardley, Michael Moore, Nick Francis,
Alastair Hay, Theo Verheij, Katherine Bradbury, Ben Ainsworth, James Raftery,
Christopher Butler, Samantha Richards-Hall, Paul Little.
Data curation: Kate Martinson.
Formal analysis: Beth Stuart, James Raftery, Shihua Zhu.
Funding acquisition: Adam W. A. Geraghty, Lucy Yardley, Beth Stuart, Michael Moore,
Nick Francis, Alastair Hay, Theo Verheij, Katherine Bradbury, Ben Ainsworth,
James Raftery, Shihua Zhu, Christopher Butler, Samantha Richards-Hall, Paul Little.
Investigation: Jane Vennik, Kate Greenwell, Laura Dennison, Paul Little.
Methodology: Jane Vennik, Adam W. A. Geraghty, Lucy Yardley, Beth Stuart,
Katherine Bradbury, Kate Greenwell, Laura Dennison, Sian Williamson, James Raftery,
Shihua Zhu, Paul Little.
Project administration: Jane Vennik, Adam W. A. Geraghty, Kate Martinson,
Sian Williamson, James Denison-Day.
Software: James Denison-Day.
Supervision: Jane Vennik, Adam W. A. Geraghty, Lucy Yardley, Paul Little.
Writing – original draft: Jane Vennik, Adam W. A. Geraghty, Paul Little.
Writing – review & editing: Jane Vennik, Adam W. A. Geraghty, Kate Martinson,
Lucy Yardley, Beth Stuart, Michael Moore, Nick Francis, Alastair Hay, Theo Verheij,
Katherine Bradbury, Kate Greenwell, Laura Dennison, Sian Williamson,
James Denison-Day, Ben Ainsworth, James Raftery, Shihua Zhu, Christopher Butler,
Samantha Richards-Hall, Paul Little.
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