Table 1

Interventions and enablers description and annual costs at the two study facilities, 2019 US$

Intervention	Description	Impact modelling			Core activities costed	Annual intervention activity costs		Enablers costed	Annual enabler costs
Intervention	Description	Implementation	Reduction in transmission in clinics	Reduction in community-wide incident TB 2021–203	Core activities costed	Clinic 1	Clinic 2	Enablers costed	Clinic 1	Clinic 2
1: Improving ventilation by opening doors and windows	Clinical staff members are assigned to check that clinic windows and doors are open throughout the day	Assume that all doors and windows in the clinic are kept open at all times	55% (IQR 25%–72%)	5.3% (range 1.3%–12.5%)	One clinical staff member doing a round of the clinic every hour	14 526	5810	1-day training for all clinical staff every 3 years and intensified supervision from district. Electric heaters/fans to ensure thermal comfort.	2645	1603
2: Building retrofits	Modifications to building structure to improve air flow	An undefined package of retrofits sufficient to increase air changes per hour to a minimum of 2 in all rooms	45% (IQR 16%–64%)	4.3% (0.8%–11.2%)	Raising roof of waiting area, installing turbine ventilators and lattice brickwork	1232	412	None	0	0
3: UVGI	Overhead ultraviolet germicidal irradiation lamps in clinic spaces	Assume that appropriate and well-maintained UVGI systems are installed in all areas	77% (IQR 64%–85%)	7.4% (3.2–14.7%)	UV lights installation, maintenance, calibration and electricity	8232	4025	One-day training for all clinical staff every 3 years	3544	1103
4: Surgical mask wearing for patients and N95 respirators for staff	Surgical masks are provided for clinic attendees and fitted N95 respirators for clinical staff	Assume that 70% of all clinic attendees wear surgical masks 90% of the time, and clinic staff wear N95 masks 50% of the time	47% (IQR 42%–50%)	4.5% (2.1%–8.8%)	One N95 respirator per staff member every five shifts, fitted annually (50% coverage). One surgical mask per patient per visit (70% coverage)	Staff: 13 675 Patients: 5682	Staff: 4103 Patients: 2841	One-day training for all clinical staff every 3 years. Free leaflet for one in ten patients disseminated around clinic	3820	1241
5: Maximising use of existing CCMDD facilities	Drug pick-up points for chronic patients that are external to clinics (eg, private pharmacies)	Assume that virally supressed HIV patients (~92% of patients on ART) can have their ART appointments reduced to once every 6 months, with the rest needing monthly appointments	22% (IQR 12%–32%)	3.4% (0.7%–8.7%)	None	–	–	Half-day training for staff involved in implementation every 3 years. Once-off community workshops.	3201	1981
6: Queue management system	Patients are triaged and directed to wait outside in an open space until their name is called	Assume that only 15–30 patients are allowed to wait inside the clinic at a time, with the rest waiting in a large, covered, well ventilated outside waiting area	83% (IQR 76%–88%)	8.0% (3.8%–15.2%)	One nurse triaging patients and one lay staff member directing queues	3008	1504	Half-day training for staff involved in implementation every 3 years and intensified supervision from district. Once-off community workshops. Covered outdoor waiting area.	3269	2048
7: Appointments system	Appointment slots are assigned throughout the day for different patient groups and longer waiting times if no appointment	Assume that all adult chronic patients and a proportion of adult acute patients can given appointments, with their appointment times spaced throughout the day	62% (IQR 45%–75%)	5.9% (2.2%–12.9%)	1 hour per day for clerk to preretrieve files and record appointments. One hour for public awareness messaging in waiting area	4426	2951	Half-day training for staff involved in implementation every 3 years. Once-off community workshops.	6401	5139

.ART, antiretroviral therapy; CMDD, Central Chronic Medicines Dispensing and Distribution; M&E, monitoring and evaluation; TB, tuberculosis; UVGI, ultraviolet germicidal irradiation.