Table 5. Questions of the topic list used to explore how public health nurses identified and prioritized contacts and scaled up a CI.

	Questions	Probing questions
Identification of contacts	How did you identify the contacts?	Did someone else than the index case assisted with naming the contacts?
	Did you measure the level of exposurebetween the contacts and the index case?	How? How did you measure the frequency/duration/intensity of exposure?
	To what extend is the list of contacts completedo you think?	Why do you think it is/is not complete? What efforts did you undertake to identify all contacts?
	How is the relationship between you and theindex case?	How was the willingness of the index case to name his/her contacts? Did you experience any barriers in identifying contacts?
Prioritization for testing	How were the contacts prioritized in thiscontact investigation?	When were the contacts prioritized? Who decided on this prioritization? Did you discuss this with the physician specialist? Why/why not?
	To what extent did you experience difficultieswith prioritizing contacts?	What were the reasons for experiencing these difficulties?
	How did you differentiate between close andcasual contacts?	Which criteria you considered most important? Duration of exposure? Frequency? Intimacy? Other criteria? Why?
	How did you differentiate between casual and community contacts	Which criteria you considered most important? Duration of exposure? Frequency? Intimacy? Other criteria? Why?
Scaling up	Were casual contacts evaluated?	How and why was decided to test casual contacts? Who made this decision
	Were casual contacts tested concurrently or subsequently of close contacts?	For what reason?
	Were community contacts tested?	How and why was decided that community contacts were tested? Who decided this? If not: How and why was decided not to test community contacts? In what hypothetically situation would you have scaled up to test casual/community contacts? Which contacts would then have been tested?