Table 1.

Evaluation of the videos and posters according to semi-structured telephone interviews with 12 institutions.

	Achievements	Challenges	Recommendations
1. Feedback on the material (posters and videos) in general	Information reached the stakeholders via different ways: • Berlin Kältehilfe list (5) • online search (2) • homeless service providers (2) • source unknown (3) Diverse and barrier-free (analog, hybrid, and digital) material was appreciated (12) Brochures and flyers continue to be popular in respondents' workplace. Regardless of the type of materials, importance was placed on: • a simple, clear, and concise message • purposeful design • multilingualism	Lack of targeted information material on health topics in general	To reach a larger population, materials should be distributed via diverse ways (e.g., mailing lists) Use diverse information modalities and combination of those to reach heterogeneous group (2) Need of similarly tailored information material on diverse (health) topics for daily work with PEH such as: personal hygiene (e.g., showering facilities) (2), preventive medical check-ups (2), medical care options also for people without health insurance or documents (2), scabies treatment, low-threshold psychiatric services, hepatitis (2), sexually transmitted infections, standard vaccinations, counseling on health insurance, safer drug use, tuberculosis, HIV, cancer prevention, and access to health services in general
2. Feedback on the vaccination posters concerning use and benefitsa	All interview partners used the posters in locations for PEH (12) Positive aspects that were mentioned: • appropriate for the counseling context • multilingualism (4) • professional design (2) • diversity-sensitive (2) • simple and clear language, suitable for functional illiterates • accepting drug policy (2) • opened the conversation on vaccination and enabled further counseling (7) • initiated conversation about taboo topics (e.g., drug consumption) (3) • enabled PEH to inform themselves ‘quietly' in their preferred language (5) • informed PEH that they had the right to receive vaccinations	It was perceived as suboptimal that posters did not contain specific information on local vaccination campaign (e.g., timing and places) (2) People have scanned the QR code to the homepage in the false assumption that they can make an appointment for vaccination (3) Posters were removed several times (without obvious vandalism) (2)	The QR-Code could link to further information on vaccinations and facilitate appointments for vaccination. Distinct local information on vaccination programmes was added directly on the posters (2) The following aspects could be considered in the posters: • poster version for those who are undecided about vaccination (with a link to a hotline or low-threshold counseling) • clear reasons/arguments pro vaccination • clarification about fake news and vaccination myths • more diversity for example in terms of women Posters can be placed in different locations such as: • outpatient clinic buses • shelters (3) • consulting sites (2) • restrooms (2) • train stations (2) • community welfare centers (2) • soup kitchens (2)
3. Feedback on the videos concerning use and benefitsb	Videos were utilized in the counseling context	“I watched the general video and thought it was great. So it's even more unfortunate that I immediately asked myself, how are we going to use this in our service because it's not actually feasible.”
		Reasons for not using the videos: • lack of time • lack of staff • lack of equipment (screens, accessible PCs or tablets, loudspeakers) (5) • rooms are often too crowded and restless (2) PEH who have a smartphone might have only limited mobile data available, which makes streaming of videos difficult (2)
4. Opinions about the use of posters for health information	Getting predesigned material is helpful Posters can initiate the conversation on specific topics Posters are a mean to spread important information in an unobtrusive way	The institutions do not have the resources to design information materials themselves Excessive information material in the facilities is overwhelming	Health-information posters should have concise information content PEH sometimes lack the conversation with people in everyday life. Social workers or medical staff can be confidants, especially when no other social network is available (2) “Individual personal contact is irreplaceable”
5. Digitalization in general	PEH that are from a younger generation attach more importance to owning a smartphone and have a greater affinity for digital media Digital material as an opportunity to reach PEH, also people experiencing hidden homelessness Helpful in counseling contexts (5)	Gap in digitalization on both sides, within the institutions and among PEH (8) Lack of appropriate equipment. Personnel, space and financial capacities are limited therefore videos could not be screened (8) Reasons why PEH are excluded from digitalization: • expenses implied • difficult in recharging the phone / digital devices • loss of device • stolen device due to lack of access to safe storage • when a smartphone is available, the volume of mobile data is limited and used sparingly	Audible material can be helpful for visually impaired people Situations and contexts in which digitalization can be useful • questionnaires • (anonymous) online counseling • interpreter service (via video call)

The answers were structured in categories commenting on achievements, challenges, and recommendations. In the case of multiple mentions of a specific aspect, the number of mentions is given in brackets.

^aAll 12 participants were familiar with the posters before the interview.

^bSix out of 12 participants were familiar with the videos before the interview.