Communicating infection control advice to the Norwegian public using a web-based Message Lab study

ISRCTN	ISRCTN11075577
DOI	https://doi.org/10.1186/ISRCTN11075577
Sponsor	Norwegian Institute of Public Health
Funder	Norwegian Institute of Public Health

Submission date: 20/04/2026
Registration date: 27/04/2026
Last edited: 07/05/2026

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Infections and Infestations

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Background and study aims
Institutes of Public Health often have responsibility for developing and communicating health advice to the public. It is not always evident how well the advice is understood among members of the public. This study will explore the effect of providing additional explanations of key terms and adding specific advice related to staying at home on intended behaviour.

Who can participate?
Healthy volunteers aged between 20 to 66 years old (working age), who speak Norwegian as native language, and reside in Norway.

What does the study involve?
The study will conduct a web-based, parallel-group, individually randomized, pragmatic superiority trial to compare the effects of different ways of communicating health advice related to newly onset symptoms of a respiratory tract infection.

What are the possible benefits and risks of participating?
The findings from this study will inform the format and wording of health advice communicated by the National Institute of Public Health.

Risks not provided at time of registration

Where is the study run from?
Norwegian Institute of Public Health, Norway.

When is the study starting and how long is it expected to run for?
April 2026 to June 2026

Who is funding the study?
Norwegian Institute of Public Health, Norway.

Who is the main contact?
Dr Heather Munthe-Kaas, heather.munthe-kaas@fhi.no

Contact information

Dr Heather Munthe-Kaas
Principal investigator, Public, Scientific

Lovisenberggata 8
Oslo
0456
Norway

ORCID ID	0000-0002-6051-9010
Phone	+47 40293266
Email	heather.munthe-kaas@fhi.no

Study information

Primary study design	Interventional
Allocation	Randomized controlled trial
Masking	Blinded (masking used)
Control	Active
Assignment	Parallel
Purpose	Basic science, Health services research
Scientific title	Communicating infection control advice to the Norwegian public: web-based randomized superiority message lab trial
Study objectives	The objectives of this randomized trial are to estimate the effects of four different modes of communicating advice related to behaviour with newly onset symptoms of respiratory infection. The primary outcome is intended behaviour based on health advice
Ethics approval(s)	Approved 23/04/2026, REK south-east B (Regional Committees for Medical and Health Research Ethics, Postboks 1130 Blindern, Oslo, 0318, Norway; +47 22845501; rek-sorost@medisin.uio.no), ref: 986882
Health condition(s) or problem(s) studied	Intended behaviour based on infection control advice.
Intervention	Intervention description (TIDieR summary) and study-arm procedures This is a web-based, individually randomised, parallel-group Message Lab trial delivered through the University of Oslo survey platform (Nettskjema; Norwegian; an English back-translation is provided in the protocol for reference). The study will use an automated, computer-based randomization process implemented in Nettskjema to allocate participants 1:1:1:1 to control or intervention. Randomization will be triggered when participants confirm study participation by clicking a button. Allocation will be concealed and handled independently of the research team, who will not have access to the randomization sequence or ability to influence treatment assignment. After opening the invitation email and providing electronic informed consent, participants complete baseline questions and an attention check. Participants are then automatically allocated to view one version of infection-control advice text about what to do when experiencing newly onset respiratory symptoms. Immediately after reading the allocated advice, participants complete outcome questions (hypothetical scenarios and additional items on understanding, trustworthiness and perceived sufficiency of information) and then submit their responses. No additional study contact or reminders are planned. Duration and follow-up (all arms): The intervention consists of a single exposure to the allocated advice text during one online session (expected completion time approximately 5–10 minutes for the full survey). Outcomes are assessed once, immediately after exposure, within the same session (no longitudinal follow-up). Study arms (what is delivered): Arm 1 – Explanations of key terms (version with explicit descriptions): Participants view the advice text that includes explicit explanations/definitions of key terms describing vulnerable groups (e.g., defining “infants” and “people at higher risk of becoming seriously ill”). The core behavioural recommendation is to avoid unnecessary close contact with people at higher risk and to practise respiratory/hand hygiene. The advice is presented as plain text on-screen in Nettskjema. No tailoring or personalisation is used beyond presenting the same text to all participants assigned to this arm. Arm 2 – Explanations + ‘usually okay to attend’ sentence: Participants view the advice text that includes (i) explicit explanations/definitions of key terms as in Arm 1, and (ii) an additional sentence stating that it is usually okay to go to work or participate in other activities if the person feels well enough, while still taking precautions to avoid infecting others. The advice is presented as plain text on-screen in Nettskjema, identical for all participants in this arm (no tailoring). Arm 3 – Current Norwegian Institute of Public Health (NIPH) web advice + ‘usually okay to attend’ sentence: Participants view the current NIPH website wording for advice about behaviour with respiratory symptoms, with an additional sentence stating that it is usually okay to go to work or participate in activities if the person feels up to it. The advice is presented as plain text on-screen in Nettskjema, identical for all participants allocated to this arm (no tailoring). Arm 4 – Control (current NIPH web advice): Participants view the current NIPH website wording for advice about staying at home/behaviour when experiencing respiratory symptoms, without additional explanations of key terms and without the added sentence about it usually being okay to go to work/participate if feeling well enough. The advice is presented as plain text on-screen in Nettskjema, identical for all participants allocated to this arm. Who provides and how: The interventions are informational messages developed by the research team based on NIPH infection-control advice and are delivered automatically by the survey platform; there is no clinician or facilitator. The messages are read by participants on their own devices. The research team will conduct user testing (three rounds as described below) and may refine wording/formatting prior to recruitment; any changes will preserve the intended contrasts between arms (presence/absence of explanations of key terms and presence/absence of the additional ‘usually okay to go to work/participate’ sentence).
Intervention type	Other
Primary outcome measure(s)	Intended behaviour measured using Self-report intended behaviour - The primary outcome is defined as the number (count) of correct responses (i.e., between 0/15 and 15/15). at Response to hypothetical scenenario
Key secondary outcome measure(s)	Correct understanding of the advice measured using data from the device comparing participants’ responses to a multiple-choice question about understanding the advice to correct responses at one time point Meeting or exceeding threshold understanding for intended behaviours measured using data from the device to calculate whether participants are responding correctly for ≥12 = 80% of the 15 questions for the 5 hypothetical scenarios at one time point Intended behaviour for each of 5 scenarios measured using data from the device showing whether a participant has responded correctly to each of the three possible behavioural responses for the intended behaviour for each scenario to be considered correct at one time point Understanding of the term “infant” measured using data from the device showing a correct response to question about the definition at one time point Understanding of the term “people with higher risk of becoming seriously ill from respiratory tract infections” measured using data from the device showing a correct response to question about the definition at one time point
Completion date	29/06/2026

Eligibility

Participant type(s)
Age group	Mixed
Lower age limit	20 Years
Upper age limit	66 Years
Sex	All
Target sample size at registration	1600
Key inclusion criteria	1. Aged between 20 to 66 years old (working age) 2. Have Norwegian as native language 3. Reside in Norway
Key exclusion criteria	Not meeting the key inclusion criteria.
Date of first enrolment	27/04/2026
Date of final enrolment	12/05/2026

Locations

Countries of recruitment

Norway

Study participating centres

Results and Publications

Individual participant data (IPD) Intention to share	No

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Protocol file	version 1.3	08/04/2026	20/04/2026	No	No

Additional files

49389_Protocol_v1.3_08April2026.pdf: Protocol file

Editorial Notes

07/05/2026: The date of final enrolment was changed from 04/05/2026 to 12/05/2026.
27/04/2026: Study’s existence confirmed by the Regional Committee for Medical and Health Research Ethics (REK) South-East B, Norway.