Table 3. Representative quotations illustrating facilitators and barriers to TB preventive treatment, by cascade step.

Cascade step	Theme	Participant, focus group	Example quotation
Prescription (facilitator)	Specialist consultations help convince doctors to prescribe	Nurse, group 8	We had the pulmonologist, who knows a lot. And it is good that he was there, because sometimes when our colleagues had doubts, we as nurses–because there is always more trust shown toward a doctor than a nurse–we could approach him.
Prescription (barrier)	Guidelines do not emphasize treatment	Pulmonologist, group 8	We are governed by a national guideline, and unfortunately, latent TB infection is given little importance in the national guideline; there are only a few paragraphs on latent TB infection.
	Lack of clear indications in guidelines	Nurse, group 8	What is not considered in the national guidelines is treatment for adults…it is not given, not considered for all adults. It would be good if they could come out with “positive PPD or IGRA” or some other indication.
	Lack of awareness of scientific evidence	Doctor, group 8	The doubts about effectiveness are widespread. In my opinion, I consider isoniazid to be a big help, that it could reduce TB incidence in Peru. But others always ask me about isoniazid or the evaluation of contacts or preventive treatment for contacts. . .People lack a lot of information, they may lack technical expertise, they lack awareness.
	Perception that treatment is not for adults	Pulmonologist, group 8	What happens is that the mentality of the majority of our colleagues is that [preventive] treatment is for children <5 years old and some people with risk factors.
	Concerns about drug resistance	Pulmonologist, group 8	There are many specialists who will argue that with the large amount of resistance we have, resistance to isoniazid in our setting, many colleagues argue that [preventive treatment] is not viable for this reason. But even if they are right, this primary resistance is not more than 10%, so there will still be benefit to preventive treatment.
Uptake (facilitator)	Counseling about rationale for treatment	Female, group 4	I was recently diagnosed with asthma…the doctor told me, “You are a person who uses corticosteroids, which means that you are a patient who is sensitive and at risk. Therefore, you should take [preventive treatment].”
	Fear of getting sick like family members	Female, group 7	When [my husband] coughed, he coughed up so much blood, almost half a bag of blood. Looking at him, I prayed to have strength for the sake of my child. So I started to take the [preventive treatment]…I saw [my husband] and said, “I do not want this to happen to me.”
Uptake (barrier)	Insurance status	Nurse, group 8	Here in Peru, we have two types of [public] insurance: the one from the Ministry of Health is SIS, which is what we work with, and EsSALUD [employer-based]. Many of our patients and families work and have other insurance, and sometimes these are the people who get [preventive] treatment prescribed. But because they have EsSALUD insurance, we cannot give them the isoniazid, and we cannot give it to their children. [EsSALUD hospitals] do not have isoniazid, so these patients or their family members come back and ask us to please give them [isoniazid], but it is complicated for us to give medications to a person who has a different insurance.
Completion (facilitator)	Family support	Female, group 4	At times I cannot go [to the health facility to pick up medications]. And my mother, because she is always going there, she picks them up for everyone and brings them to us.
	Community health workers offer support	Female, group 3	[Community health workers] have more training to be able to give you information. And if you have any doubts, you ask them, and they know how to respond. In contrast, a family member at times will tell you “fine, well, take [the medication] or don’t take it.”
	Personal strategies for remembering to take medications	Females, group 4	Participant 1: “I leave the pills on the table to remind myself” Participant 2: “I put them in my wallet.”
	SMS reminders help people remember to take medications	Female, group 2	They are hanging over their phones all day—they eat like that, have breakfast like that, with their phones. So when [the SMS] comes, with its notification tone, they remember.
Completion (barrier)	Medication fatigue and long treatment	Female, group 6	It has been very difficult for my daughter. She did not want to take [preventive treatment]. She took it for the first months. Then she got tired of it, she was sick of it and did not want to take it. She shouted and cried ‘I don’t want these pills.’
	Anticipated or experienced adverse events	Female, group 1	When my brother-in-law, when he takes [preventive treatment], he tells me that it gives him nausea, or maybe affects his liver. Well, I would like to take three months and no more.
	Inconvenience of weekly medication refills	Female, group 5	At times, we do not have the time to pick up the mediations weekly. There is no time to go and pick them up. In my case, I work in rotating shifts, and sometimes I do not have time to go….Could medication pickups be every two weeks instead? Weekly is very short.
	Difficulty giving pills to children	Female, group 3	My son suffers taking it. Although he chews it, the bitter flavor stays in his mouth, and he cries.
	Forgetting while busy	Female, group 5	Sometimes I would go to the health facility early with my daughter, or I would have something to do early, and I would come back late. And on these days I did not take the pills because I left the house very early and I left the pills at home.
	SMS reminders are not useful for everyone	Male, group 1	There are times when one may be sent a message–let’s say one sees it in the afternoon…but the person who saw it in the afternoon may continue their routine into the night and forget.

Additional supporting quotations can be found in S4 Table.