Please be aware: This document has been corrected.
Heidi L. Moline, MD1; Ayzsa Tannis, MPH1; Ariana P. Toepfer, MPH1; John V. Williams, MD2,3; Julie A. Growth, MD4,5; Janet A. Englund, MD6; Natasha B. Halasa, MD7; Mary Allen Staat, MD8,9; Geoffrey A. Weinberg, MD10; Rangaraj Selvarangan, PhD11; Marian G. Michaels, MD2,3; Leila C. Sahni, PhD4,5; Eileen J. Klein, MD6; Laura S. Stewart, PhD7; Elizabeth P. Schlaudecker, MD8,9; Peter G. Szilagyi, MD10; Jennifer E. Schuster, MD12; Leah Goldstein, MPH1; Samar Musa, MPH2,3; Pedro A. Piedra, MD4,5; Danielle M. Zerr, MD6; Kristina A. Betters, MD7; Chelsea Rohlfs, MBA9; Christina Albertin, MPH10; Dithi Banerjee, PhD12; Erin R. McKeever, MPH1; Casey Kalman, MPH1; Benjamin R. Clopper, MPH1; New Vaccine Surveillance Community Product Effectiveness Collaborators; Meredith L. McMorrow, MD1,*; Fatimah S. Dawood, MD1,* (View creator affiliations)
View recommended citationSummary
What’s already recognized about this matter?
Respiration syncytial virus (RSV) is the main reason behind hospitalization amongst U.S. babies. In August 2023, CDC really helpful nirsevimab, a long-acting monoclonal antibody, to offer protection to babies elderly <8 months in opposition to RSV-associated decrease respiration tract an infection of their first RSV season.
What’s added by way of this document?
Nirsevimab effectiveness was once 90% in opposition to RSV-associated hospitalization in babies of their first RSV season. Median time from receipt of nirsevimab to symptom onset was once get started highlight45 days (IQR = 19–76).
What are the consequences for public well being follow?
To scale back the chance for RSV-associated hospitalization, babies will have to be secure by way of maternal RSV vaccination or toddler receipt of nirsevimab.
Shut
Summary
Respiration syncytial virus (RSV) is the main reason behind hospitalization amongst babies in the US. In August 2023, CDC’s Advisory Committee on Immunization Practices really helpful nirsevimab, a long-acting monoclonal antibody, for babies elderly <8 months to offer protection to in opposition to RSV-associated decrease respiration tract an infection right through their first RSV season and for kids elderly 8–19 months at higher threat for critical RSV illness. In segment 3 scientific trials, nirsevimab efficacy in opposition to RSV-associated decrease respiration tract an infection with hospitalization was once 81% (95% CI = 62%–90%) via 150 days after receipt; post-introduction effectiveness has now not been assessed in the US. On this research, the New Vaccine Surveillance Community evaluated nirsevimab effectiveness in opposition to RSV-associated hospitalization amongst babies of their first RSV season right through October 1, 2023–February 29, 2024. Amongst 699 babies hospitalized with acute respiration sickness, 59 (8%) gained nirsevimab ≥7 days prior to symptom onset. Nirsevimab effectiveness was once 90% (95% CI = 75%–96%) in opposition to RSV-associated hospitalization with an average time from receipt to symptom onset of 45 days (IQR = 19–76 days). The choice of babies who gained nirsevimab was once too low to stratify by way of length from receipt; alternatively, nirsevimab effectiveness is predicted to lower with expanding time after receipt as a result of antibody decay. Even though nirsevimab uptake and the period from receipt of nirsevimab have been restricted on this research, this early estimate helps the present nirsevimab advice for the prevention of critical RSV illness in babies. Babies will have to be secure by way of maternal RSV vaccination or toddler receipt of nirsevimab.
Advent
Respiration syncytial virus (RSV) is the main reason behind hospitalization in U.S. babies, chargeable for 50,000–80,000 hospitalizations every year in youngsters elderly <5 years (1,2). The perfect hospitalization charges happen right through the primary months of lifestyles, and threat declines with expanding age in infancy and right through early adolescence (3). In August 2023, CDC’s Advisory Committee on Immunization Practices (ACIP) really helpful nirsevimab, a long-acting monoclonal antibody, for all babies elderly <8 months born right through or getting into their first RSV season, and for kids elderly 8–19 months at higher threat for critical RSV illness and getting into their 2nd RSV season (4). In a pooled research of information from prelicensure randomized placebo-controlled scientific trials, 1 dose of nirsevimab given at age <8 months was once 79% efficacious in opposition to medically attended RSV-associated decrease respiration tract an infection and 81% efficacious in opposition to RSV-associated decrease respiration tract an infection with hospitalization via 150 days after injection (4). In September 2023, a maternal RSV vaccine additionally changed into to be had to stop RSV illness in younger babies. ACIP recommends both nirsevimab or maternal RSV vaccination to offer protection to babies born right through or getting into their first RSV season (5). In October 2023, according to nirsevimab shortages, CDC really helpful that well being care settings with restricted provide of nirsevimab prioritize nirsevimab for babies elderly <6 months and babies with underlying prerequisites at perfect threat for critical illness (6). In January 2024, further doses of nirsevimab changed into to be had, and CDC really helpful that well being care settings with good enough nirsevimab provide go back to the unique ACIP suggestions for nirsevimab use (7). This research supplies the primary U.S. estimate for post-introduction nirsevimab effectiveness amongst U.S. babies right through their first RSV season.
Strategies
Information Assortment and Inclusion Standards
The New Vaccine Surveillance Community (NVSN) is a population-based, potential surveillance platform for acute respiration sickness (ARI) in babies, youngsters, and youngsters elderly <18 years that displays pediatric respiration viruses at seven U.S. pediatric instructional scientific facilities to evaluate immunization effectiveness.† Demographic, scientific, and immunization information have been systematically accumulated via dad or mum/mother or father interviews, scientific file abstraction, and state immunization data programs. Respiration specimens have been accumulated from enrolled youngsters and examined for RSV and different not unusual respiration viruses by way of real-time opposite transcription–polymerase chain response.§ Receipt of nirsevimab was once ascertained via dad or mum document and verified via state immunization data programs, start health facility, or number one care supplier data.¶
Babies have been eligible for this research in the event that they have been elderly <8 months as of October 1, 2023, or born after October 1, 2023, have been hospitalized with ARI** right through October 1, 2023–February 29, 2024, and had verified nirsevimab standing, reported gestational age at start, and scientific file overview to evaluate for underlying scientific prerequisites. Babies have been excluded in the event that they have been enrolled prior to nirsevimab changed into to be had at their web page,†† gained any doses of palivizumab, had reported maternal RSV vaccination right through being pregnant, or inconclusive or unknown RSV verify effects. For a web page to be incorporated on this research, a minimum of 5 babies enrolled on the web page needed to have gained nirsevimab ≥7 days prior to symptom onset.
Information Research
Nirsevimab effectiveness in opposition to RSV-associated hospitalization was once estimated the usage of a test-negative, case-control design. Case-patients have been babies who gained a favorable RSV verify consequence. Regulate sufferers have been babies who gained a damaging RSV verify consequence. Babies have been thought to be nirsevimab recipients in the event that they gained nirsevimab ≥7 days prior to symptom onset to account for RSV incubation duration and time to top antibody focus.§§ Babies who gained nirsevimab <7 days prior to symptom onset have been excluded. Pearson’s chi-square checks have been used to match demographic traits amongst case-patients and management sufferers and by way of nirsevimab standing. Effectiveness was once estimated the usage of multivariable logistic regression fashions, evaluating the chances of receipt of nirsevimab amongst case-patients and management sufferers. Regression fashions managed for age at enrollment in months, month of sickness, enrollment web page, and presence of a number of high-risk scientific prerequisites for critical RSV illness.¶¶ Preterm standing (start at <28, 28–31, 32–33, 34–36, and ≥37 weeks’ gestation) and insurance coverage sort have been evaluated as attainable confounders however didn’t trade estimates and weren’t incorporated within the ultimate type. Effectiveness was once calculated as (1− adjusted odds ratio) × 100%. Analyses have been carried out the usage of SAS instrument (model 9.4; SAS Institute). This task was once reviewed by way of CDC, deemed now not analysis, and was once carried out in line with appropriate federal regulation and CDC coverage.***
Effects
Amongst 1,036 eligible babies, 699 babies at 4 websites met inclusion standards,††† together with 407 (58%) case-patients and 292 (42%) management sufferers (Desk). Receipt of nirsevimab was once extra common amongst babies with high-risk scientific prerequisites than the ones with out those prerequisites (46% as opposed to 6%, p<0.001). There was once no distinction within the frequency of receipt of nirsevimab by way of preterm standing or insurance coverage sort. Time since receipt of nirsevimab to ARI symptom onset ranged from 7 to 127 days with an average of 45 days (IQR = 19–76 days) (Determine). General, six (1%) case-patients and 53 (18%) management sufferers gained nirsevimab; amongst all incorporated babies, receipt of nirsevimab ranged from 4% to twelve% by way of web page. Nirsevimab effectiveness was once 90% (95% CI = 75–96) in opposition to RSV-associated hospitalization.
Dialogue
On this multisite research of 699 babies hospitalized with ARI right through their first RSV season, receipt of nirsevimab was once 90% efficient in opposition to RSV-associated hospitalization at an average of 45 days from receipt of nirsevimab to ARI symptom onset. This early effectiveness estimate helps current suggestions for the prevention of critical RSV illness in babies of their first RSV season.
The strengths of this primary estimate of U.S. post-introduction nirsevimab effectiveness come with enrollment of babies the usage of a standardized ARI definition, systematic RSV checking out, and receipt of nirsevimab verification with state immunization data programs or scientific data for all babies. Alternatively, it is very important be aware that nirsevimab effectiveness right through a complete RSV season is predicted to be less than the estimate reported right here, as a result of antibody ranges from passive immunization wane through the years. On this research, the median period from receipt of nirsevimab was once 45 days, while the median length of the U.S. RSV season prior to the COVID-19 pandemic was once 189 days (8). In scientific trials, nirsevimab remained extremely efficacious in opposition to RSV-associated decrease respiration tract an infection in babies via 150 days after receipt of nirsevimab, in line with a longer half-life of 63–73 days (9).
Estimating effectiveness underneath real-world prerequisites for the total length of an RSV season and in youngsters elderly 8–19 months at excessive threat for critical RSV illness who’re really helpful to obtain nirsevimab prior to their 2nd RSV season stays vital. Thus, CDC will proceed to observe nirsevimab effectiveness.
Boundaries
The findings on this document are topic to a minimum of 5 boundaries. First, just a small percentage of hospitalized babies with ARI gained nirsevimab, most likely partly as a result of not on time availability on this first season of creation and intermittent provide shortages, and babies who gained nirsevimab have been much more likely to have underlying prerequisites.§§§ Thus, effects may not be absolutely generalizable to all babies eligible for receipt of nirsevimab of their first RSV season. 2d, the low choice of case-patients who gained nirsevimab didn’t permit for stratified estimates by way of time since receipt of nirsevimab. 3rd, as a result of nirsevimab changed into to be had at maximum websites in the US after seasonal RSV circulate started, some babies on this research may have had RSV an infection prior to receipt of nirsevimab, which may have affected estimated effectiveness. Fourth, nirsevimab effectiveness was once now not estimated by way of dosage (50 mg for babies weighing <5 kg or 100 mg for babies weighing ≥5 kg) as a result of nirsevimab dosage was once now not ascertained. In spite of everything, the effectiveness estimate on this document is restricted to the prevention of RSV-associated hospitalization. RSV amongst babies additionally reasons a substantial build up in outpatient and emergency division visits; further research are warranted to evaluate nirsevimab effectiveness in opposition to those results.
Implications for Public Well being Follow
Receipt of a unmarried dose of nirsevimab was once extremely efficient in opposition to RSV-associated hospitalization in babies getting into their first RSV season. This discovering helps present CDC suggestions that every one babies will have to be secure by way of maternal RSV vaccination or toddler receipt of nirsevimab, to cut back the chance for RSV-associated hospitalization of their first RSV season (4,6).
New Vaccine Surveillance Community Product Effectiveness Collaborators
Ruth Hyperlink-Gelles, Coronavirus and Different Respiration Viruses Department, Nationwide Middle for Immunization and Respiration Sicknesses, CDC; Amanda Payne, Coronavirus and Different Respiration Viruses Department, Nationwide Middle for Immunization and Respiration Sicknesses, CDC; Ryan Wiegand, Coronavirus and Different Respiration Viruses Department, Nationwide Middle for Immunization and Respiration Sicknesses, CDC; Ximena Aguilera Correa, Division of Pediatrics, Vanderbilt College Clinical Middle; Claudia Guevara Pulido, Division of Pediatrics, Vanderbilt College Clinical Middle; Hanna Grioni, Division of Pediatrics, Seattle Kids’s Clinic; Bonnie Strelitz, Division of Pediatrics, Seattle Kids’s Clinic; Vasanthi Avadhanula, Baylor Faculty of Medication; Flor M. Munoz, Texas Kids’s Clinic and Baylor Faculty of Medication; Wende Fregoe, Division of Pediatrics, College of Rochester Clinical Middle and College of Rochester–Golisano Kids’s Clinic; Saranya Peri, Division of Pathology and Laboratory Medication, Kids’s Mercy Kansas Town; Anjana Sasidharan, Division of Pathology and Laboratory Medication, Kids’s Mercy Kansas Town; Monika Johnson, Division of Pediatrics, College of Pittsburgh College of Medication; Klancie Dauer, Division of Pediatrics, College of Pittsburgh College of Medication.
1Coronavirus and Different Respiration Viruses Department, Nationwide Middle for Immunization and Respiration Sicknesses, CDC; 2UPMC Kids’s Clinic of Pittsburgh, Pittsburgh, Pennsylvania; 3Department of Pediatrics, College of Pittsburgh College of Medication, Pittsburgh, Pennsylvania; 4Texas Kids’s Clinic, Houston, Texas; 5Baylor Faculty of Medication, Houston, Texas; 6Department of Pediatrics, Seattle Kids’s Clinic, Seattle, Washington; 7Department of Pediatrics, Vanderbilt College Clinical Middle, Nashville, Tennessee; 8Division of Infectious Sicknesses, Cincinnati Kids’s Clinic Clinical Middle, Cincinnati, Ohio; 9Department of Pediatrics, College of Cincinnati Faculty of Medication, Cincinnati, Ohio; 10Department of Pediatrics, College of Rochester Clinical Middle and College of Rochester–Golisano Kids’s Clinic, Rochester, New York; 11Department of Pathology and Laboratory Medication, Kids’s Mercy Clinic, Kansas Town, Missouri; 12Department of Pediatrics Kids’s Mercy Clinic, Kansas Town, Missouri.
References
Suh M, Movva N, Jiang X, et al. Respiration syncytial virus is the main reason behind United States toddler hospitalizations, 2009–2019: a learn about of the Nationwide (National) Inpatient Pattern. J Infect Dis 2022;226(Suppl 2):S154–63. PMID:35968878
Corridor CB, Weinberg GA, Iwane MK, et al. The load of respiration syncytial virus an infection in babies. N Engl J Med 2009;360:588–98. PMID:19196675
Curns AT, Rha B, Energetic JY, et al. Respiration syncytial virus–related hospitalizations amongst youngsters <5 years outdated: 2016 to 2020. Pediatrics 2024;153:e2023062574. PMID:38298053
Jones JM, Fleming-Dutra KE, Prill MM, et al. Use of nirsevimab for the prevention of respiration syncytial virus illness amongst babies and babies: suggestions of the Advisory Committee on Immunization Practices—United States, 2023. MMWR Morb Mortal Wkly Rep 2023;72:920–5. PMID:37616235
Fleming-Dutra KE, Jones JM, Roper LE, et al. Use of the Pfizer respiration syncytial virus vaccine right through being pregnant for the prevention of respiration syncytial virus–related decrease respiration tract illness in babies: suggestions of the Advisory Committee on Immunization Practices—United States, 2023. MMWR Morb Mortal Wkly Rep 2023;72:1115–22. PMID:37824423
CDC. Emergency preparedness and reaction: restricted availability of nirsevimab in the US—meantime CDC suggestions to offer protection to babies from respiration syncytial virus (RSV) right through the 2023–2024 respiration virus season. Atlanta, GA: US Division of Well being and Human Products and services, CDC; 2023.
CDC. COCA Now: up to date steerage for healthcare suppliers on higher on provide of nirsevimab to offer protection to babies from critical respiration syncytial virus (RSV) right through the 2023–2024 respiration virus season. Atlanta, GA: US Division of Well being and Human Products and services, CDC; 2024.
Hamid S, Winn A, Parikh R, et al. Seasonality of respiration syncytial virus—United States, 2017–2023. MMWR Morb Mortal Wkly Rep 2023;72:355–61. PMID:37022977
Hammitt LL, Dagan R, Yuan Y, et al. ; MELODY Learn about Crew. Nirsevimab for prevention of RSV in wholesome late-preterm and time period babies. N Engl J Med 2022;386:837–46. PMID:35235726
TABLE. Traits of babies born right through or getting into their first respiration syncytial virus season who have been hospitalized with acute respiration sickness, by way of respiration syncytial virus verify consequence and receipt of nirsevimab*,† — New Vaccine Surveillance Community, October 2023–February 2024
Feature
General general,
no. (column %)
RSV verify consequence
Receipt of nirsevimab
Sure
no. (column %)
Damaging
no. (column %)
p-value§
Sure
no. (row %)
No
no. (row %)
p-value§
All youngsters
699
407 (58)
292 (42)
—
59 (8)
640 (92)
—
Age crew at admission, mos
<1
111 (16)
51 (13)
60 (21)
<0.001
10 (9)
101 (91)
0.028
1–2
214 (31)
144 (35)
70 (24)
18 (8)
196 (92)
3–4
131 (19)
90 (22)
41 (14)
9 (7)
122 (93)
5–6
121 (17)
67 (16)
54 (18)
6 (5)
115 (95)
7–8
96 (14)
49 (12)
47 (16)
9 (9)
87 (91)
9–10
23 (3)
6 (1)
17 (6)
6 (26)
17 (74)
11–12
3 (0)
0 (—)
3 (1)
1 (33)
2 (67)
Gestational age
Preterm (<37 wks)¶
146 (21)
77 (19)
69 (24)
0.129
15 (10)
131 (90)
0.377
Time period (≥37 wks)
551 (79)
329 (81)
222 (76)
44 (8)
507 (92)
Unknown
2 (0)
1 (0)
1 (0)
0 (—)
2 (100)
Top-risk scientific situation**
None
660 (94)
396 (97)
264 (90)
<0.001
41 (6)
619 (94)
<0.001
≥1
39 (6)
11 (3)
28 (10)
18 (46)
21 (54)
Intercourse
Feminine
293 (42)
182 (45)
111 (38)
0.076
28 (10)
265 (90)
0.367
Male
406 (58)
225 (55)
181 (62)
31 (8)
375 (92)
Race and ethnicity††
American Indian or Alaska Local
1 (0)
1 (0)
0 (—)
0.002
0 (—)
1 (100)
0.511
Asian
47 (7)
27 (7)
20 (7)
3 (6)
44 (94)
Black or African American
89 (13)
41 (10)
48 (16)
8 (9)
81 (91)
Local Hawaiian or different Pacific Islander
225 (32)
126 (31)
99 (34)
23 (10)
202 (90)
White
30 (4)
12 (3)
18 (6)
5 (17)
25 (83)
Hispanic or Latino
8 (1)
3 (1)
5 (2)
0 (—)
8 (100)
More than one race or different non-specified
280 (40)
188 (46)
92 (32)
18 (6)
262 (94)
Unknown
19 (3)
9 (2)
10 (3)
2 (11)
17 (89)
Insurance coverage standing
Public
385 (55)
198 (49)
187 (64)
<0.001
37 (10)
348 (90)
0.296
Personal
233 (33)
155 (38)
78 (27)
17 (7)
216 (93)
Private and non-private
4 (1)
2 (0)
2 (1)
1 (25)
3 (75)
Self-pay (none)
51 (7)
31 (8)
20 (7)
4 (8)
47 (92)
Unknown
26 (4)
21 (5)
5 (2)
0 (—)
26 (100)
Website
Houston, TX
195 (28)
110 (27)
85 (29)
0.050
24 (12)
171 (88)
0.013
Nashville, TN
93 (13)
47 (12)
46 (16)
9 (10)
84 (90)
Pittsburgh, PA
235 (34)
153 (38)
82 (28)
9 (4)
226 (96)
Seattle, WA
176 (25)
97 (24)
79 (27)
17 (10)
159 (90)
RSV verify consequence
Sure
407 (58)
NA
NA
—
6 (1)
401 (99)
<0.001
Damaging
292 (42)
NA
NA
53 (18)
239 (82)
Abbreviations: BPAP = bilevel certain airway force; CPAP = steady certain airway force; NA = now not appropriate; RSV = respiration syncytial virus.
* General, 337 babies enrolled right through the research duration have been excluded. Causes for exclusion incorporated enrollment at websites with fewer than 5 babies who had gained nirsevimab (296 from Rochester, Cincinnati, and Kansas Town), receipt of nirsevimab <7 days prior to symptom onset (20), lacking or inconclusive RSV verify consequence (20), maternal receipt of RSV vaccine right through being pregnant (22), and receipt of palivizumab (10); causes for exclusion aren’t mutually unique.
† Present season receipt of nirsevimab documented by way of registry or supplier (654: 94%) or scientific file handiest (45: 6%).
§ Pearson’s chi-square checks have been used to match demographic traits amongst case-patients and management sufferers and by way of receipt of nirsevimab.
¶ <28 weeks (12: 2%); 28–31 weeks (12: 2%); 32–33 weeks (48: 7%); 34–36 weeks (74: 11%).
** Top-risk scientific prerequisites have been outlined as persistent lung illness of prematurity (bronchopulmonary dysplasia, bronchiolitis obliterans, persistent respiration failure with CPAP/BIPAP/ventilator, pulmonary high blood pressure [neonatal, primary, or secondary], or interstitial lung illness) (12); hemodynamically vital congenital middle illness (abnormalities of aortic arch, hypoplastic left middle syndrome, pulmonary atresia, tricuspid atresia, Tetralogy of Fallot, transposition of the nice arteries, partial or general anomalous pulmonary venous go back, different abnormalities of middle valves, double outlet proper ventricle, or different congenital middle malformations) (21); critical immunocompromise (one); critical cystic fibrosis (two); neuromuscular illness (autonomic disorder, instability or dysautonomia, agenesis or hypoplasia of the corpus callosum, muscular dystrophy or spinal muscular atrophy, issues of tone, or different neuromuscular situation) (12); or congenital pulmonary abnormalities that impair the power to transparent secretions (none).
†† Individuals of Hispanic or Latino (Hispanic) foundation could be of any race however are categorised as Hispanic; all racial teams are non-Hispanic.
FIGURE. Time from receipt of nirsevimab* to symptom onset amongst babies born right through or getting into their first respiration syncytial virus season who have been hospitalized with acute respiration sickness, by way of respiration syncytial virus verify consequence — New Vaccine Surveillance Community, October 2023–February 2024
Abbreviation: RSV = respiration syncytial virus.
* Days 0–6 aren’t incorporated as a result of babies with receipt of nirsevimab inside of 7 days of symptom onset have been excluded from this research.
Urged quotation for this newsletter: Moline HL, Tannis A, Toepfer AP, et al. Early Estimate of Nirsevimab Effectiveness for Prevention of Respiration Syncytial Virus–Related Hospitalization Amongst Babies Getting into Their First Respiration Syncytial Virus Season — New Vaccine Surveillance Community, October 2023–February 2024. MMWR Morb Mortal Wkly Rep 2024;73:209–214. DOI:
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