Update on respiratory syncytial virus hospitalizations among U.S. preterm and term infants before and after the 2014 American Academy of Pediatrics policy on immunoprophylaxis: 2011-2017

Figures & data

Table 1. Commercially insured and medicaid-insured infants by risk cohort

	Commercially Insured Infants		Medicaid-Insured Infants
	n	%	n	%
Number of insured infants born July 1, 2010, to June 30, 2017	1,596,603	100.0	2,011,591	100.0
AND linkable to birth hospitalization	1,585,442	99.3	2,005,681	99.7
AND discharged from birth hospitalization	1,583,610	99.2	1,998,923	99.4
Infants included in the study
All included	975,096	61.6	1,299,070	65.0
Early preterm infants (29–30 wGA)	5,800	0.6	9,853	0.8
Early preterm infants (31–32 wGA)	11,319	1.2	18,264	1.4
Moderate preterm infants (33–34 wGA)	29,749	3.1	43,433	3.3
Term infants without major health problems	928,228	95.2	1,227,520	94.5
Infants excluded from the study
Rare, complex medical conditions^a population infants	3,500	0.2	4,604	0.2
Chronic lung disease of prematurity infants	1,754	0.1	2,048	0.1
Congenital heart disease infants	26,756	1.7	27,491	1.4
Early preterm infants (<29 wGA)	6,609	0.4	12,903	0.6
Late preterm infants (35–36 wGA)	64,119	4.0	101,729	5.1
Other preterm infants^b	39,560	2.5	25,258	1.3
Term infants with major health problems	158,015	10.0	143,390	7.2
Other unknown infants^b	308,201	19.5	382,430	19.1

^aCystic fibrosis, immunodeficiency, congenital anomalies of the respiratory system, neuromuscular disease, other neuromuscular, immunologic, or genetic conditions or organ transplants are included in this group.

^bInsufficient data in the claims record to assign gestational age.

Table 2. Characteristics of infants aged <6 months born during the study period at 29–34 wGA or term without major health problems

	July 2011 to June 2014^a				July 2014 to June 2017^a
	Preterm 29–34 wGA		Term		Preterm 29–34 wGA		Term
	n	%	n	%	n	%	n	%
Commercially insured infants	26,289		555,009		18,496		349,424
Sex
Male	14,195	54.0	276,694	49.9	10,008	54.1	173,613	49.7
Female	12,094	46.0	278,315	50.1	8,488	45.9	175,811	50.3
Health Plan Type
Comprehensive/indemnity	111	0.4	3,021	0.5	239	1.3	4,825	1.4
EPO/PPO	17,720	67.4	369,758	66.6	11,503	62.2	215,811	61.8
POS/POS with capitation	1,696	6.5	35,322	6.4	1,319	7.1	21,030	6.0
HMO	3,227	12.3	58,271	10.5	1,617	8.7	25,553	7.3
CDHP/HDHP	2,123	8.1	54,877	9.9	3,155	17.1	67,563	19.3
Unknown	1,412	5.4	33,760	6.1	663	3.6	14,642	4.2
Region
Northeast	4,591	17.5	116,031	20.9	3,263	17.6	72,903	20.9
New England Division	715	2.7	21,128	3.8	599	3.2	13,948	4.0
Middle Atlantic Division	3,876	14.7	94,903	17.1	2,664	14.4	58,955	16.9
Midwest	6,762	25.7	160,060	28.8	4,110	22.2	89,603	25.6
East North Central Division	5,310	20.2	121,006	21.8	3,080	16.7	64,071	18.3
West North Central Division	1,452	5.5	39,054	7.0	1,030	5.6	25,532	7.3
South	9,286	35.3	184,583	33.3	7,704	41.7	123,140	35.2
South Atlantic Division	4,252	16.2	80,813	14.6	3,899	21.1	56,685	16.2
East South Central Division	1,380	5.2	27,302	4.9	1,227	6.6	21,813	6.2
West South Central Division	3,654	13.9	76,468	13.8	2,578	13.9	44,642	12.8
West	4,945	18.8	87,108	15.7	3,126	16.9	59,637	17.1
Mountain Division	1,673	6.4	48,580	8.8	1,283	6.9	32,677	9.4
Pacific Division	3,272	12.4	38,528	6.9	1,843	10.0	26,960	7.7
Unknown	705	2.7	7,227	1.3	293	1.6	4,141	1.2
Medicaid-insured infants	34,311		639,840		36,048		581,971
Sex
Male	18,035	52.6	316,689	49.5	18,840	52.3	289,248	49.7
Female	16,184	47.2	321,147	50.2	17,207	47.7	292,717	50.3
Unknown	92	0.3	2,004	0.3	1	0.0	6	0.0
Health Plan Type
Comprehensive/POS^b	16,577	48.3	299,561	46.8	14,787	41.0	231,302	39.7
Other^b	17,734	51.7	340,279	53.2	21,261	59.0	350,669	60.3
Race/Ethnicity
White	14,319	41.7	308,012	48.1	10,326	28.6	195,318	33.6
Black	12,988	37.9	187,230	29.3	10,006	27.8	131,489	22.6
Hispanic	2,161	6.3	53,943	8.4	1,633	4.5	40,680	7.0
Other/unknown	4,843	14.1	90,655	14.2	14,083	39.1	214,484	36.9

CDHP, consumer-driven health plan; EPO, exclusive provider organization; HDHP, high-deductible health plan; HMO, health maintenance organization; POS, point of service; PPO, preferred provider organization.

^aInfants aged <6 months born between January 2, 2014, and June 30, 2014, may appear in both cohorts.

^bPlans may be capitated.

Table 3. Commercially insured and medicaid-insured infants by risk cohort born between July 1, 2010, and June 30, 2017, who contributed time to the 2011 to 2017 RSV seasons while aged <6 months

	Commercially Insured Infants				Medicaid-Insured Infants
	November 2011 to March 2014		November 2014 to March 2017		November 2011 to March 2014		November 2014 to March 2017
	Infants	Infant-Seasons	Infants	Infant-Seasons	Infants	Infant-Seasons	Infants	Infant-Seasons
29–34 wGA	18,770	9,041.2	13,116	6,402.5	25,628	13,072.6	27,021	13,281.9
29–30 wGA	2,136	944.6	1,480	662.7	3,335	1,577.9	3,371	1,510.5
31–32 wGA	4,501	2,114.1	2,938	1,432.0	6,428	3,199.2	6,758	3,272.5
33–34 wGA	12,133	5,982.5	8,698	4,307.8	15,865	8,295.5	16,892	8,498.9
Term infants without MHP	418,711	215,306.7	261,319	136,108.2	501,399	271,815.4	456,090	240,885.9

MHP, major health problems.

Table 4. RSV IP use among commercially insured and medicaid-insured infants by risk cohort

	Commercially Insured Infants							Medicaid-Insured Infants
	2011–2014			2014–2017			Absolute Decrease (% Decrease)	2011–2014			2014–2017			Absolute Decrease (% Decrease)
	No. of Infants	No. With RSV IP	% With RSV IP^a	No. of Infants	No. With RSV IP	% With RSV IP^a		No. of Infants	No. With RSV IP	% With RSV IP^a	No. of Infants	No. With RSV IP	% With RSV IP^a
<3 months^b
29–30 wGA	1,400	473	33.8	947	59	6.2	28 (82)	2,206	698	31.6	2,185	90	4.1	28 (87)
31–32 wGA	3,126	1,021	32.7	1,917	48	2.5	30 (92)	4,411	1,328	30.1	4,639	88	1.9	28 (94)
33–34 wGA	8,573	1,825	21.3	5,931	43	0.7	21 (97)	11,307	1,943	17.2	11,835	93	0.8	16 (95)
3-<6 months^b
29–30 wGA	1,729	852	49.3	1,246	196	15.7	34 (68)	2,795	1,350	48.3	2,771	281	10.1	38 (79)
31–32 wGA	3,412	1,080	31.7	2,383	133	5.6	26 (82)	5,109	1,301	25.5	5,303	165	3.1	22 (88)
33–34 wGA	8,961	1,040	11.6	6,529	58	0.9	11 (92)	11,927	971	8.1	12,620	153	1.2	7 (85)

^aP values comparing 2014–2017 vs. 2011–2014 within gestational age and insurer are all <0.001.

^bAge is captured at any point in the RSV season. Infants may appear in multiple age categories.

Figure 1. RSV hospitalization rates with 95% confidence intervals for 2011–2014 and 2014–2017 RSV seasons by wGA among infants with A) commercial or B) Medicaid insurance

Figure 2. Unadjusted rate ratios for (A) RSV hospitalization and (B) all-cause bronchiolitis hospitalization by season for preterm infants aged <6 months by gestational age relative to term infants aged <6 months

Abbreviations: COM, commercial; MED, Medicaid.

Table 5. Change in RSV hospitalization risk and all-cause bronchiolitis risk from 2011–2014 to 2014–2017 among preterm infants aged <6 months compared with the change in risk among term infants aged <6 months

	Commercially Insured Infants				Medicaid-Insured Infants
	Difference-in-Difference for RSVH (95% CI)	P Value	Difference-in-Difference for All-Cause BH (95% CI)	P Value	Difference-in-Difference for RSVH (95% CI)	P Value	Difference-in-Difference for All-Cause BH (95% CI)	P Value
29–34 wGA	2.09 (1.58–2.75)	<.001	1.93 (1.55–2.40)	<.001	1.76 (1.52–2.02)	<.001	1.73 (1.54–1.94)	<.001
29–30 wGA	1.90 (0.97–3.72)	.063	1.72 (1.02–2.89)	.040	2.34 (1.71–3.20)	<.001	2.25 (1.75–2.89)	<.001
31–32 wGA	2.56 (1.76–3.73)	<.001	2.32 (1.70–3.16)	<.001	1.69 (1.35–2.10)	<.001	1.75 (1.46–2.10)	<.001
33–34 wGA	1.87 (1.44–2.43)	<.001	1.79 (1.44–2.22)	<.001	1.37 (1.18–1.60)	<.001	1.31 (1.15–1.50)	<.001

BH, bronchiolitis hospitalization.

Figure 3. All-cause bronchiolitis hospitalization rates with 95% confidence intervals for 2011–2014 and 2014–2017 RSV seasons by wGA among infants with A) commercial or B) Medicaid insurance

Table 6. RSV hospitalization characteristics among preterm and term infants aged <6 months

	Commercially Insured Infants				Medicaid-Insured Infants
	July 2011 to June 2014		July 2014 to June 2017		July 2011 to June 2014		July 2014 to June 2017
	N/mean/median	SD/%	N/mean/median	SD/%	N/mean/median	SD/%	N/mean/median	SD/%
29–34 wGA, <3 months
Number of infants with RSVH	117		130		391		486
Number of RSVH	132		135		416		508
Time from birth hospitalization discharge to first RSVH, mean, days	35.7	20.7	37.5	20.5	34.7	19.2	34.8	19.5
Time from birth hospitalization discharge to first RSVH, median, days	35.0		35.5		31.0		32.0
Average length of stay, mean, days	7.3	6.3	7.6	6.8	8.9	11.8	9.8	10.8
Average length of stay, median, days	5.0		5.0		6.0		7.0
Admission to ICU, n	44	37.6%	55	42.3%	183	46.8%	260	53.5%
RSVH costs,^a mean	$41,480	$60,717	$45,891	$70,320	$17,660	$33,954	$27,063	$54,985
RSVH costs, median	$15,500		$19,747		$6,600		$9,291
Term, <3 months
Number of infants with RSVH	1,771		863		3,544		2,464
Number of RSVH	1,827		893		3,689		2,553
Time from birth hospitalization discharge to first RSVH, mean, days	43.9	21.8	44.1	21.8	45.1	21.6	45.8	21.7
Time from birth hospitalization discharge to first RSVH, median, days	41.0		42.0		44.0		44.0
Average length of stay, mean, days	4.5	3.0	4.7	5.9	4.8	4.4	5.0	3.9
Average length of stay, median, days	4.0		4.0		4.0		4.0
Admission to ICU, n	261	14.7%	172	19.9%	615	17.4%	572	23.2%
RSVH costs,^a mean	$14,175	$26,298	$18,963	$33,815	$8,889	$35,892	$10,652	$29,834
RSVH costs, median	$8,382		$10,722		$3,554		$4,436
29–34 wGA, 3-<6 months
Number of infants with RSVH	91		104		247		305
Number of RSVH	93		112		258		315
Time from birth hospitalization discharge to first RSVH, mean, days	112.2	34.7	106.6	29.1	112.0	32.4	104.9	30.2
Time from birth hospitalization discharge to first RSVH, median, days	116.0		105.5		111.0		102.0
Average length of stay, mean, days	4.8	6.0	5.4	4.8	5.6	4.3	6.1	7.4
Average length of stay, median, days	3.0		4.0		4.5		5.0
Admission to ICU, n	14	15.4%	22	21.2%	54	21.9%	98	32.1%
RSVH costs,^a mean	$20,410	$77,353	$25,828	$60,740	$8,810	$23,997	$12,906	$68,924
RSVH costs, median	$8,344		$12,756		$3,795		$3,821
Term, 3-<6 months
Number of infants with RSVH	848		479		1,866		1,348
Number of RSVH	875		491		1,920		1,391
Time from birth hospitalization discharge to first RSVH, mean, days	131.1	26.8	131.8	26.9	130.5	26.8	130.1	26.4
Time from birth hospitalization discharge to first RSVH, median, days	130.0		130.0		129.0		129.0
Average length of stay, mean, days	3.7	2.1	4.0	3.0	4.1	3.3	4.7	5.0
Average length of stay, median, days	3.0		3.0		3.0		4.0
Admission to ICU, n	84	9.9%	73	15.2%	205	11.0%	258	19.1%
RSVH costs,^a mean	$11,008	$15,096	$15,467	$23,725	$5,598	$20,376	$7,002	$13,345
RSVH costs, median	$7,348		$9,544		$3,125		$3,679

^aHospitalizations with $0 cost were excluded.