Effectiveness of palivizumab in preventing respiratory syncytial virus infection in high-risk children

Figures & data

Figure 1. Flow diagram for study participants

Abbreviations: PVZ, palivizumab; RT-PCR, reverse transcription-polymerase chain reaction.

Table 1. Characteristics of cases and controls

	Total N: 142 n (%)	RSV-positive cases N: 35 n (%)	RSV-negative controls N: 107 n (%)	P-value
Sex				0.3385
Male	75 (53)	21 (60)	54 (50)
Female	67 (47)	14 (40)	53 (50)
Age, months
0–5	83 (58)	16 (46)	67 (63)	Reference
6–11	35 (25)	8 (23)	27 (25)	0.6590
12–17	12 (8)	7 (20)	5 (5)	0.0073
18–23	12 (8)	4 (11)	8 (7)	0.2707
Season				0.4013
2011–12	18 (13)	3 (9)	15 (14)
2012–13	4 (3)	2 (5)	2 (2)
2013–14	9 (6)	3 (9)	6 (6)
2014–15	26 (18)	5 (14)	21 (20)
2015–16	16 (11)	5 (14)	11 (10)
2016–17	36 (25)	7 (20)	29 (27)
2017–18	16 (11)	7 (20)	9 (8)
2018–19	17 (12)	3 (9)	14 (13)
Doses of Palivizumab				0.1645
0	40 (28)	15 (43)	25 (23)
1	13 (9)	2 (6)	11 (10)
2	35 (25)	7 (20)	28 (26)
≥3	54 (38)	11 (31)	43 (41)
Palivizumab within 30 d				0.0722
Yes	91 (64)	18 (51)	73 (68)
No	51 (36)	17 (49)	34 (32)
Any dose of palivizumab				0.0261
Yes	102 (72)	20 (57)	82 (77)
No	40 (28)	15 (43)	25 (23)
Healthcare setting				0.4373
Hospitalization	76 (54)	21 (60)	55 (51)
Outpatient consultation	66 (46)	14 (40)	52 (49)

Table 2. Characteristics of cases by prophylactic immunization status

	Palivizumab N: 20 n (%)	No Palivizumab N: 15 n (%)	P value
Sex			0.7282
Male	11 (55)	10 (67)
Female	9 (45)	5 (33)
Age, months			0.3008
0–5	7 (35)	9 (60)
6–11	6 (30)	2 (13)
12–23	7 (35)	4 (27)
Season			0.1516
2011–12	2 (10)	1 (7)
2012–13	1 (5)	1 (7)
2013–14	0 (0)	3 (20)
2014–15	3 (15)	2 (13)
2015–16	3 (15)	2 (13)
2016–17	3 (15)	4 (27)
2017–18	7 (35)	0 (0)
2018–19	1 (5)	2 (13)
RSV subgroup			0.2911
A	12 (60)	5 (33)
B	7 (35)	9 (60)
Unknown	1 (5)	1 (7)
Healthcare setting			0.1632
Hospital admission	10 (50)	11 (73)
Outpatient consultation	10 (50)	4 (27)

Table 3. Effectiveness of prophylactic immunization with palivizumab in preventing laboratory-confirmed cases of respiratory syncytial virus

Analysis	Cases Treated/Total	Controls Treated/Total	Effectiveness*	95% CI	P value
All patients
Any dose of palivizumab vs. none	20/35	82/107	70%	19 to 90	0.0148
Palivizumab dose in prior 30 d vs. none	18/33	73/98	68%	13 to 89	0.0238
Hospitalized patients
Any dose of palivizumab vs. none	10/21	42/55	82%	29 to 96	0.0102
Palivizumab dose in prior 30 d vs. none	9/20	36/49	79%	16 to 96	0.0234
RSV subgroup A
Any dose of palivizumab vs. none	12/17	65/86	87%	−181 to 87	0.6472
Palivizumab dose in prior 30 d vs. none	10/15	57/78	38%	−192 to 86	0.6882
RSV subgroup B
Any dose of palivizumab vs. none	7/16	56/79	79%	12 to 96	0.0307
Palivizumab dose in prior 30 d vs. none	7/16	48/71	75%	−10 to 95	0.0695

*Exact logistic regression analysis adjusted by age group (0–5, 6–11, 12–23 months) and healthcare setting (outpatient or hospitalization).

CI, confidence interval