Table 2. Summary of findings organized by themes within the RE-AIM dimensions.

Dimensions	Themes	Facilitators	Barriers	Potential Solutions
Reach	Making Contact	Dialer software used to replace caller’s personal phone number with a health department number	Low answer rate	Introduce text messages to introduce phone calls; obtain outreach preferences at testing
	Establishing Rapport	Dialer software used to replace caller’s personal phone number with a health department number	Lack of trust in an unknown caller	Routinely address privacy concerns
		Many cases and contacts willing to participate out of a desire to help their community	Low public unawareness of contact tracing leading to lack of interest or comfort in providing information about contacts	Organize public awareness campaigns; provide thorough explanations for why contact tracing is important for the community
Effectiveness	Delays	--	Late reporting of test results	Automate test reporting and transfer of information to contact tracers
			Unknown language preferences	Verify language preferences at point-of-testing
	Community Needs	Health department routinely assesses needs as part of outreach	Lack of money, or adequate food & housing to help cases to adhere to isolation & quarantine	Increase funding for financial, nutritional, and housing supports; better inform tracers about how such needs can be met
Adoption	Volunteer Motivations	Partnerships with academic institutions and students	--	Reward non-employed tracers with academic credit or certificates of experience
	Time Management	Weekly availability survey used for case investigation team	Shifting volunteer availability	Offer flexible, volunteer-driven scheduling
			Inconsistent workload due to varying case incidence with skill loss from inactivity	Ensure consistent baseline involvement with longitudinal skill refreshers
	Knowledge	Brief, targeted training provided to new volunteer tracers	Need for broad mastery of diverse content areas including biology, guidelines, procedures	Offer self-directed, online training modules to obtain baseline and knowledge
		Many volunteers had previous education or experiences in health sciences	Frequent changes to guidelines due to evolving understanding of COVID-19 transmission dynamics	Frequently revise protocols to reflect changing guidelines, and rapidly communicate of these changes to the tracers; provide repository of potential call scenarios for outreach workers to learn from.
	Skills	Many volunteers previously trained in patient communication skills	Need for effective communication skills for building rapport	Incorporate role-plays and simulations to build up communication skills during training
	Collaborative Learning	Leaders regularly responded to questions by e-mail or GroupMe*	Lack of communication with leadership and feedback to ensure quality performance	Integrate two-way communication via messaging apps, email, and supervisory support
			Sense of isolation and lack of community while working remotely	Encourage peer mentorship, buddy systems, and regular, small-group peer meetings
Implementation	Tools	Software was flexible and allowed case investigators to adapt it to the interview at-hand.	Impersonal, non-conversational script	Personalize script and allow for adaptation to the clients’ needs.
			Lack of interoperability of electronic systems	Provide simple and standardized data collection tools
		Health department adapted script according to volunteer suggestions	Loss of volunteer privacy	Offer and/or require use of call masking software
			Need for specialized protocols for key populations†	Develop and apply specialized protocols
	External Coordination	--	Duplicate calls to the same cases or contacts, leading to frustration and decreased engagement	Coordination with other clinics, laboratories, and health organizations to streamline and integrate communication
Maintenance	Sustainability	--	High volunteer turnover; decreasing motivation over time	Offer payment or other compensation and acknowledgement such as academic credit or certificates of experience

*Mobile app for hosting chat-groups

†Asymptomatic cases, residents of congregate settings, minors, non-English speakers, household contact.