Table 1

Characteristics of children included in the study, that is, all births in Ontario occurring 1 January 1993 to 31 December 2016, stratified by palivizumab eligibility group

Characteristic	Ineligible		Possibly eligible		Eligible
	N	%	N	%	N	%
	n=2 837 145		n=1 43 913		n=34 301
Birth characteristics
Birth year
1993–1996	462 235	16.29	22 377	15.55	7015	20.45
1997–2000	443 707	15.64	23 284	16.18	6732	19.63
2001–2004	464 534	16.37	23 595	16.40	5670	16.53
2005–2008	494 542	17.43	24 291	16.88	5197	15.15
2009–2012	487 847	17.19	24 607	17.10	4939	14.40
2013–2016	484 280	17.07	25 759	17.90	4748	13.84
High risk birth month (November–January)	655 754	23.11	42 315	29.40	9832	28.66
Sex (female)	1 387 750	48.91	65 046	45.20	15 317	44.65
Multiple birth	53 151	1.87	28 868	20.06	7473	21.79
Estimated wGA
<28 wGA (extremely preterm)	1753	0.06	261	0.18	11 338	33.05
28–32 wGA (very preterm)	2973	0.10	377	0.26	15 408	44.92
33–36 wGA (preterm)	30 620	1.08	131 800	91.58	2095	6.11
37+ wGA (term)	2 763 110	97.39	10 935	7.60	5309	15.48
Missing	38 689	1.36	540	0.38	151	0.44
Weight group
<1500 g	4337	0.15	2852	1.98	22 672	66.10
1500–1999 g	6562	0.23	25 261	17.55	4360	12.71
2000–2499 g	70 582	2.49	45 815	31.84	1251	3.65
2500–2999 g	423 850	14.94	42 265	29.37	1823	5.31
3000–3499 g	1 069 534	37.70	20 878	14.51	2201	6.42
3500–3999 g	902 861	31.82	5147	3.58	1390	4.05
4000–4499 g	301 482	10.63	1253	0.87	470	1.37
4500 g +	57 937	2.04	442	0.31	134	0.39
Mean weight, g (SD)	3438.42	503.43	2495.50	579.44	1512.84	958.70
Congenital diseases†
Any major congenital anomaly	49 968	1.76	19 550	13.58	13 137	38.30
CHD	0	–	13 453	9.35	11 239	32.77
Hemodynamically significant CHD	0	–	0	–	6596	19.23
Other CHD	0	–	13 453	9.35	4643	13.54
Major congenital airway anomaly	0	–	1980	1.38	349	1.02
Other clinical diagnoses†
Bronchopulmonary dysplasia/ chronic lung disease	0	–	0	–	4311	12.57
Trisomy 21	0	–	1044	0.73	173	0.50
Sociodemographic characteristics *
Mother’s immigration status
Canadian born	2 207 476	77.81	112 047	77.86	26 804	78.14
Long-term resident, 5+ years	332 367	11.71	17 810	12.38	4176	12.17
Short-term resident,<5 years	293 622	10.35	13 837	9.61	3261	9.51
Refugee	3680	0.13	219	0.15	60	0.17
Maternal age
<18 years	64 765	2.28	3743	2.60	1081	3.15
19–24	428 232	15.09	21 141	14.69	5385	15.70
25–29	828 752	29.21	38 524	26.77	9300	27.11
30–34	969 408	34.17	47 281	32.85	10 761	31.37
35–39	458 174	16.15	26 592	18.48	6192	18.05
40+	87 758	3.09	6626	4.60	1579	4.60
Mean maternal age (SD)	29.73	5.44	30.13	5.79	29.88	5.93
Neighbourhood income quintile
1 (lowest 20% income)	626 463	22.08	33 814	23.50	442	1.29
2	567 822	20.01	29 532	20.52	8575	25.00
3	568 979	20.05	28 662	19.92	7193	20.97
4	581 546	20.50	28 524	19.82	6603	19.25
5 (highest 20% income)	467 644	16.48	22 175	15.41	6530	19.04
Missing	24 691	0.87	1206	0.84	4958	14.45
Residence at time of birth
Urban	2 518 452	88.77	129 573	90.04	30 057	87.63
Rural	307 202	10.83	13 763	9.56	4047	11.80
Missing	11 491	0.41	577	0.40	197	0.57
Geographically isolated residence	23 391	0.82	97	0.07	1041	3.03

Statistically significant difference between eligibility groups noted across all characteristics; p<0.0001.
*Determined at the time of birth.
†Diagnosed before second birthday.
BPD, bronchopulmonary dysplasia; CHD, congenital heart disease; CLD, chronic lung disease; wGA, weeks gestational age.