Table 2.

Demographic and clinical characteristics of household contacts and their index cases

ID	Sex	Age, years	Clinical form of the index casea	Bacillary index of the index case	Number of BCG scars b	Anti-PGL-I (OD450 value)c	Positive/N egative for anti-PGL-I
Household contacts that did not develop leprosy (HCNDL)
HCNDL01	Female	62	BT	0	ns	0.113	negative
HCNDL02	Female	66	BL	1.00	ns	0.19	negative
HCNDL03	Male	27	LL	5.50	2	0.292	negative
HCNDL04	Male	55	BL	1.00	ns	0.011	negative
HCNDL05	Male	50	TT	0	1	0.028	negative
HCNDL06	Female	62	BL	1.00	ns	0.466	positive
HCNDL07	Female	31	BL	0.50	1	0.15	negative
HCNDL08	Female	55	BL	1.00	1	0.031	negative
HCNDL09	Male	60	BT	0	ns	0.008	negative
HCNDL10	Male	22	BL	0.50	2	0.029	negative
HCNDL11	Female	45	BL	4.25	1	0.121	negative
HCNDL12	Female	21	BT	0	2	0.100	negative
HCNDL13	Female	26	BL	1.00	2	0.034	negative
HCNDL14	Male	42	BL	1.00	ns	0.055	negative
HCNDL15	Female	48	BL	1.00	1	0.149	negative
HCNDL16	Female	65	LL	4.25	1	0.079	negative
HCNDL17	Male	32	BL	1.00	1	0.050	negative
Household contacts that developed leprosy (HCDL)
HCDL01	Female	54	BL	1.83	1	0.13	negative
HCDL02	Female	57	BL	3.33	ns	0.46	positive
HCDL03	Female	67	BL	3.00	ns	0.22	negative
HCDL04	Male	24	LL	2.16	1	0.390	positive
HCDL05	Female	24	LL	2.50	2	0.840	positive
HCDL06	Male	21	LL	4.75	1	0.470	positive
HCDL07	Male	48	LL	4.25	ns	0.63	positive
HCDL08	Male	21	BL	3.00	2	0.410	positive
HCDL09	Male	18	LL	4.16	1	0.32	positive
HCDL10	Female	34	BB	1.33	ns	1.26	positive
HCDL11	Female	37	LL	3.66	1	0.50	positive
HCDL12	Male	55	LL	4.25	ns	0.51	positive
HCDL13	Female	31	LL	4.66	ns	0.200	negative
HCDL14	Female	42	BL	3.00	ns	0.340	positive
HCDL15	Female	23	BB	1.75	1	0.179	negative
HCDL16	Female	39	BL	1.50	ns	0.350	positive
HCDL17	Female	36	LL	4.25	1	0.114	negative

Abbreviations: na - not available; ns - no scars were found it; TT - tuberculoid leprosy; BT - borderline tuberculoid; BB - borderline borderline; BL - borderline lepromatous; LL - lepromatous leprosy. The sera samples were collected from the household contacts (HCDL and HCNDL) at the diagnosis of index case (considered as time zero). According to the National Notifiable Conditions System database (SINAM; ministry of health of Brazil) none of the HCNDL individuals exhibited clinical signs or symptoms of leprosy during the period of January/2007 – December/2020.

^aclinical manifestations of leprosy were classified according to Ridley-Jopling criteria ².

^bSimilar to many previous studies, we used the number of BCG scars as a proxy for BCG vaccination record (Supplementary methods).

^cSera collected were assayed for the presence of anti-phenolic glycolipid 1 immunoglobulin M by a specific enzyme-linked immunosorbent assay. The antigen used in ELISA was NT-P-BSA (synthetic native trisaccharide of PGL-1 coupled to BSA through a 3-phenylpropanoyl). A cutoff value of 0.30, at an optical density at 450 nm (OD₄₅₀), was set for positive responses.