NCT04520659 is a Phase 1 clinical trial of RSV LID/ΔM2-2/1030s in RSV Infection, sponsored by National Institute of Allergy and Infectious Diseases (NIAID).

Who is sponsoring NCT04520659?

NCT04520659 is sponsored by National Institute of Allergy and Infectious Diseases (NIAID).

What drugs are being tested in NCT04520659?

Interventions in NCT04520659: RSV LID/ΔM2-2/1030s, Placebo.

What condition does NCT04520659 study?

NCT04520659 studies RSV Infection.

Is NCT04520659 still recruiting?

NCT04520659 is currently completed. Last updated 22 August 2025.

Are results published for NCT04520659?

Yes — primary outcome results have been posted to ClinicalTrials.gov. See the outcomes section above for details.

Last reviewed 2025-08-22 · How we verify

NCT04520659

Name: Drug Landscape Pharmaceutical Database
Creator: Drug Landscape
Published: 2026-01-01
License: https://creativecommons.org/licenses/by/4.0/

Evaluating the Infectivity, Safety and Immunogenicity of a Recombinant Live-Attenuated Respiratory Syncytial Virus Vaccine, LID/ΔM2-2/1030s, in RSV-Seronegative Infants and Children 6 to 24 Months of Age

Completed Phase 1 Results posted Last updated 22 August 2025

What this trial tests

Phase 1 trial testing RSV LID/ΔM2-2/1030s in RSV Infection in 81 participants. Completed in 18 April 2024.

Timeline

16 March 2022

Primary endpoint
18 April 2024

18 April 2024

Quick facts

Lead sponsor	National Institute of Allergy and Infectious Diseases (NIAID)
Phase	Phase 1
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	quadruple
Primary purpose	prevention
Enrollment	81
Start date	16 March 2022
Primary completion	18 April 2024
Estimated completion	18 April 2024
Sites	3 locations across United States

Drugs / interventions tested

RSV LID/ΔM2-2/1030s — full drug profile →
Placebo

Conditions studied

RSV Infection — all drugs for RSV Infection →

Sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

Who can join

Adults 6 Months to 24 Months, any sex, with RSV Infection. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Frequency of Grade 1 or Higher Solicited Adverse Events (AEs) by Grade Primary · Measured through Day 28

Solicited adverse events include fever; otitis media; upper respiratory illness (URI); lower respiratory illness (LRI) and cough (without LRI) as defined in Appendix III of the protocol document. The number of participants who experienced solicited adverse events was presented. A participant was only counted once in each solicited AE category, and that is in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 16 and Table 17 in the pro

Fever

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	27
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	41
Groups 1 and 2 Combined: Placebo	18
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	8
Group 2: Placebo	4
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	8
Groups 1 and 2 Combined: Placebo	4
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	4
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	4
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	3
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	3

Upper Respiratory

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	4
Group 1: Placebo	4
Group 2: RSV LID/ΔM2-2/1030s	13
Group 2: Placebo	12
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	17
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	9
Group 1: Placebo	3
Group 2: RSV LID/ΔM2-2/1030s	24
Group 2: Placebo	7
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	33
Groups 1 and 2 Combined: Placebo	10
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	3
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	4
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Lower Respiratory Illness (LRI) with RSV shedding

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	39
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	53
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

LRI in the absence of RSV shedding

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	54
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Cough without LRI

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	11
Group 1: Placebo	6
Group 2: RSV LID/ΔM2-2/1030s	29
Group 2: Placebo	16
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	40
Groups 1 and 2 Combined: Placebo	22
Group 1: RSV LID/ΔM2-2/1030s	2
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	9
Group 2: Placebo	3
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	11
Groups 1 and 2 Combined: Placebo	3
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	1
Group 2: RSV LID/ΔM2-2/1030s	2
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	3
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Otitis media

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	37
Group 2: Placebo	18
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	51
Groups 1 and 2 Combined: Placebo	25
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	3
Group 2: Placebo	2
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	3
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Frequency of Grade 2 or Higher Lower Respiratory Infections (LRI) by Grade Primary · Measured through Day 28

LRI may include wheezing, pneumonia, laryngotracheobronchitis (croup), rhonchi and rales as defined in Appendix III of the protocol document. A participant was only counted once in each LRI category, and that is in the line corresponding to the highest grade adverse event they had in that category. These events were graded (Grade 1-mild to Grade 4-life-threatening) following protocol-defined grading system outlined in Table 16 and Table 17 in the protocol document.

Wheezing

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	54
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Pneumonia

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	54
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Laryngotracheobronchitis (Croup)

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	39
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	53
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Rhonchi

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	54
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Rales

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	54
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Number of Participants With Unsolicited Adverse Events (AEs) by Grade of Severity Primary · Measured through Day 28

Unsolicited adverse events were other events, not included in the solicited AEs. The number of participants who experienced unsolicited adverse events was presented.

Nasal Congestion

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	6
Group 2: RSV LID/ΔM2-2/1030s	29
Group 2: Placebo	18
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	43
Groups 1 and 2 Combined: Placebo	24
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	1
Group 2: RSV LID/ΔM2-2/1030s	11
Group 2: Placebo	2
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	11
Groups 1 and 2 Combined: Placebo	3
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Emesis

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	37
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	49
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	3
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	4
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Diarrhea

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	13
Group 1: Placebo	6
Group 2: RSV LID/ΔM2-2/1030s	37
Group 2: Placebo	19
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	50
Groups 1 and 2 Combined: Placebo	25
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	1
Group 2: RSV LID/ΔM2-2/1030s	3
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	3
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Conjunctivitis

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	19
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	52
Groups 1 and 2 Combined: Placebo	26
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Pain

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	6
Group 2: RSV LID/ΔM2-2/1030s	40
Group 2: Placebo	19
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	54
Groups 1 and 2 Combined: Placebo	25
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	1
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Rash

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	13
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	39
Group 2: Placebo	19
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	52
Groups 1 and 2 Combined: Placebo	26
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	2
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Urinary tract infection

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14
Group 1: Placebo	7
Group 2: RSV LID/ΔM2-2/1030s	39
Group 2: Placebo	20
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	53
Groups 1 and 2 Combined: Placebo	27
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Number of Participants Who Experienced Serious Adverse Events (SAEs) Primary · Measured Day 0 through Day 56 after inoculation and During the RSV Surveillance Season (Date of seasonal pause in enrollment in year of inoculation through March 31)

A Serious Adverse Event (SAE) is an AE, whether considered related to the study product or not, that: Results in death during the period of protocol-defined surveillance; Is life threatening: defined as an event in which the patient was at immediate risk of death at the time of the event; it does not refer to an event that hypothetically might have caused death were it more severe; Requires inpatient hospitalization (or prolongation of existing hospitalization): defined as at least an overnight stay in the hospital or emergency ward for treatment that would have been inappropriate if administ

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0

Percentage of Vaccinees With a ≥4-fold Rise in Serum RSV-neutralizing Antibody Titer Primary · Measured at Day 0 and Day 56

Serum RSV-neutralizing antibody titers were assessed by 60% RSV-plaque reduction neutralization titer (RSV-PRNT) assay. Antibody responses were defined as a greater than or equal to 4-fold increase in titer in paired specimens, between pre-inoculation and post-inoculation time points.

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 2: RSV LID/ΔM2-2/1030s	26
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	38

Peak Titer of Vaccine Virus Shed by Reverse Transcription Polymerase Chain Reaction (RT-qPCR) (Group 1 Only) Primary · Measured at Days 5, 7, 10, 12 and additional illness visits between Days 0 and 28.

This is the mean of the highest value per participant of the titer of vaccine virus shed. It was measured by RT-qPCR. Group 1 participants only. Only participants who met the definition of infection with vaccine virus were included.

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	6.6	± 1.3

Number of Vaccinees Infected With RSV Vaccine Virus in Group 1 Primary · Measured through Day 56

Defined as shedding vaccine virus, detected by RT-qPCR, and/or ≥4-fold rise in RSV-specific serum antibodies, detected by enzyme-linked immunosorbent assay (ELISA) against the RSV F protein and/or an RSV-PRNT from study entry to Study Day 56

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	14

Frequency of RSV-medically Attended Acute Respiratory Illness (MAARI) by Grade in Vaccine and Placebo Recipients Who Experience Natural Infection With Wild Type RSV During the Subsequent RSV Season Secondary · Measured during RSV season (from date of seasonal pause in enrollment in the year of inoculation through March 31)

The number of participants who had RSV-associated, symptomatic, medically attended respiratory and febrile illness (MAARI) among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal swabs collected during illness visits for MAARI events or a \> 2.5-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events. A participant was only counted once in each solicited AE category, and that is in the line corresponding t

Fever

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	8
Group 1: Placebo	4
Group 2: RSV LID/ΔM2-2/1030s	15
Group 2: Placebo	7
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	23
Groups 1 and 2 Combined: Placebo	11
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	3
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	3
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	3
Group 2: Placebo	2
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	3
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	5
Group 1: Placebo	1
Group 2: RSV LID/ΔM2-2/1030s	6
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	11
Groups 1 and 2 Combined: Placebo	2

Upper Respiratory Illness

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	6
Group 1: Placebo	2
Group 2: RSV LID/ΔM2-2/1030s	12
Group 2: Placebo	4
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	18
Groups 1 and 2 Combined: Placebo	6
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	2
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	7
Group 1: Placebo	3
Group 2: RSV LID/ΔM2-2/1030s	15
Group 2: Placebo	5
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	22
Groups 1 and 2 Combined: Placebo	8
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Lower Respiratory Illness with RSV

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	11
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	26
Group 2: Placebo	10
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	37
Groups 1 and 2 Combined: Placebo	15
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	2
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0

LRI in the absence of RSV

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	11
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	25
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	36
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	2
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	2
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	4
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Cough without LRI

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	8
Group 1: Placebo	2
Group 2: RSV LID/ΔM2-2/1030s	12
Group 2: Placebo	5
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	20
Groups 1 and 2 Combined: Placebo	7
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	1
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	2
Group 1: RSV LID/ΔM2-2/1030s	5
Group 1: Placebo	2
Group 2: RSV LID/ΔM2-2/1030s	15
Group 2: Placebo	5
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	20
Groups 1 and 2 Combined: Placebo	7
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Otitis media

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	8
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	16
Group 2: Placebo	8
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	24
Groups 1 and 2 Combined: Placebo	13
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	5
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	11
Group 2: Placebo	3
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	16
Groups 1 and 2 Combined: Placebo	3
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Frequency of RSV-medically Attended Acute Lower Respiratory Illness (MAALRI) by Grade in Vaccine and Placebo Recipients Who Experience Natural Infection With Wild Type RSV During the Subsequent RSV Season Secondary · Measured during RSV season (from date of seasonal pause in enrollment in the year of inoculation through March 31)

The number of participants who had RSV-associated, symptomatic, medically attended acute lower respiratory illness (MAALRI) among those who had indicators of natural infection with wt RSV were presented. Natural infection with wt RSV during the RSV season surveillance was defined as having either RSV detected in nasal swabs collected during illness visits for MAALRI events or a ≥ 2.5-fold rise in serum antibodies from pre- to post-RSV season in the absence of RSV-associated medical events. A participant was only counted once in each LRI category, and that is in the line corresponding to the hi

Wheezing

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	26
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	38
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0

Pneumonia

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	26
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	38
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	2
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Bronchitis

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	27
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	39
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	1
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

laryngotracheobronchitis (Croup)

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	11
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	26
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	37
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	2
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	3
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Rhonchi

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	13
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	27
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	40
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Rales

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	13
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	26
Group 2: Placebo	11
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	39
Groups 1 and 2 Combined: Placebo	16
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	1
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	1
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Bronchiolitis

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	13
Group 1: Placebo	5
Group 2: RSV LID/ΔM2-2/1030s	27
Group 2: Placebo	10
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	40
Groups 1 and 2 Combined: Placebo	15
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	1
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	1
Group 1: RSV LID/ΔM2-2/1030s	0
Group 1: Placebo	0
Group 2: RSV LID/ΔM2-2/1030s	0
Group 2: Placebo	0
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	0
Groups 1 and 2 Combined: Placebo	0

Percentage of Vaccinees With a ≥4-fold Rise in Serum RSV preF IgG and/or RSV postF IgG Secondary · Measured at Day 0 and Day 56

Serum RSV preF IgG titers and RSV postF IgG titers were assessed by an Enzyme-linked Immunosorbent Assay (ELISA). Antibody responses were defined as a ≥4-fold increase in titer in paired specimens, between pre-inoculation and post-inoculation time points.

RSV PreF IgG

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	9
Group 2: RSV LID/ΔM2-2/1030s	22
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	31

RSV PostF IgG

Group	Value	95% CI
Group 1: RSV LID/ΔM2-2/1030s	12
Group 2: RSV LID/ΔM2-2/1030s	28
Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s	40

Adverse events — posted to ClinicalTrials.gov

Time frame: From study entry to end of study. The duration of follow-up for a given participant was between 6 and 13 months for both Groups 1 & 2 depending on time of enrollment.. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Group 1: RSV LID/ΔM2-2/1030s

Serious: 1/14 (7%)

Deaths: 0/14

Group 1: Placebo

Serious: 0/7 (0%)

Deaths: 0/7

Group 2: RSV LID/ΔM2-2/1030s

Serious: 0/60 (0%)

Deaths: 0/40

Group 2: Placebo

Serious: 0/20 (0%)

Deaths: 0/20

Groups 1 and 2 Combined: RSV LID/ΔM2-2/1030s

Serious: 1/74 (1%)

Deaths: 0/54

Groups 1 and 2 Combined: Placebo

Serious: 0/27 (0%)

Deaths: 0/27

Serious adverse events (1 terms)

Reaction	System	Group 1: RSV LID/ΔM2-2/1030s	Group 1: Placebo	Group 2: RSV LID/ΔM2-2/1030s	Group 2: Placebo	Groups 1 and 2 Combined: R…	Groups 1 and 2 Combined: P…
Wheezing	Respiratory, thoracic and mediastinal disorders	—	—	—	—	—	—

Other adverse events (12 terms — click to expand)

Reaction	System	Group 1: RSV LID/ΔM2-2/1030s	Group 1: Placebo	Group 2: RSV LID/ΔM2-2/1030s	Group 2: Placebo	Groups 1 and 2 Combined: R…	Groups 1 and 2 Combined: P…
Rhinorrhea	Respiratory, thoracic and mediastinal disorders	—	—	—	—	—	—
Cough	Respiratory, thoracic and mediastinal disorders	—	—	—	—	—	—
Fever	General disorders	—	—	—	—	—	—
Nasal congestion	Respiratory, thoracic and mediastinal disorders	—	—	—	—	—	—
Vomiting	Gastrointestinal disorders	—	—	—	—	—	—
Diarrhea	Gastrointestinal disorders	—	—	—	—	—	—
Otitis media	Infections and infestations	—	—	—	—	—	—
Pain	General disorders	—	—	—	—	—	—
Conjunctivitis	Infections and infestations	—	—	—	—	—	—
Rash	Skin and subcutaneous tissue disorders	—	—	—	—	—	—
Urinary Tract Infection	Infections and infestations	—	—	—	—	—	—
Croup	Respiratory, thoracic and mediastinal disorders	—	—	—	—	—	—

Most-reported serious reactions: Wheezing.

Data from ClinicalTrials.gov NCT04520659 adverse events section.

Sponsor's own description

The purpose of this study is to evaluate the infectivity, safety, and immunogenicity of a single dose of a recombinant, live-attenuated respiratory syncytial virus (RSV) vaccine, LID/ΔM2-2/1030s, in RSV-seronegative infants and children 6 to 24 months of age.

Publications & conference data

8 peer-reviewed publications reference this trial (live from Europe PMC):

Respiratory syncytial virus prevention within reach: the vaccine and monoclonal antibody landscape.
Mazur NI, Terstappen J, Baral R, Bardají A, et al · · 2023 · cited 294× · PMID 35952703 · DOI 10.1016/s1473-3099(22)00291-2
Respiratory Syncytial Virus Vaccines: A Review of the Candidates and the Approved Vaccines.
Topalidou X, Kalergis AM, Papazisis G. · · 2023 · cited 84× · PMID 37887775 · DOI 10.3390/pathogens12101259
Development of Nasal Vaccines and the Associated Challenges.
Nian X, Zhang J, Zhang J, Huang S, et al · · 2022 · cited 33× · PMID 36297419 · DOI 10.3390/pharmaceutics14101983
Landscape of respiratory syncytial virus.
Duan Y, Liu Z, Zang N, Cong B, et al · · 2024 · cited 17× · PMID 39501814 · DOI 10.1097/cm9.0000000000003354
New Insights on Respiratory Syncytial Virus Prevention.
Kopera E, Czajka H, Zapolnik P, Mazur A. · · 2023 · cited 16× · PMID 38140201 · DOI 10.3390/vaccines11121797
Current strategies and perspectives for active and passive immunization against Respiratory Syncytial Virus in childhood.
Scotta MC, Stein RT. · · 2023 · cited 16× · PMID 36402228 · DOI 10.1016/j.jped.2022.10.004
Nanoplatform Based Intranasal Vaccines: Current Progress and Clinical Challenges.
Bai Z, Wan D, Lan T, Hong W, et al · · 2024 · cited 14× · PMID 39185745 · DOI 10.1021/acsnano.3c10797
Evaluation of Clinical Case Definitions for Respiratory Syncytial Virus Lower Respiratory Tract Infection in Young Children.
Englund JA, Cohen RA, Bianco V, Domachowske JB, et al · · 2023 · cited 12× · PMID 37142551 · DOI 10.1093/jpids/piad028

Verify or expand the search:

Other recruiting trials for RSV Infection

Currently open trials in the same condition.

NCT06881953 — Prevention Strategy for Respiratory Syncytial Virus (RSV) Infections in Infants in France · recruiting
NCT06866405 — A Phase 3 Study of Revaccination in Subsequent Pregnancies With Bivalent RSV Vaccine and Duration of Protection of a Sin · Phase 3 · recruiting
NCT06843317 — Safety and Immunogenicity Study of Revaccination With SCB-1019T in Healthy Adults · Phase 1 · recruiting
NCT06172660 — Real-World Effectiveness of Perinatal RSV Immunoprophylaxis · recruiting
NCT06640387 — CARE-ID: Dynamics of Respiratory Infections in Children and Transmission in Households and Schools · recruiting

Other National Institute of Allergy and Infectious Diseases (NIAID) trials

Trials by the same sponsor.

NCT07216794 — Small Trial of Alendronate Impact on the Reservoir of HIV · Phase 2 · not yet recruiting
NCT07215858 — BPL-1357 Against H1N1 Influenza Virus Challenge · Phase 2 · recruiting
NCT06987318 — A Study to Evaluate the Safety and Antiviral Activity of Two Human Monoclonal Antibodies (VRC07-523LS and PGT121.414.LS) · Phase 1 · not yet recruiting
NCT07124559 — A Study of Daily Rifapentine Combined With Isoniazid (1HP) for Tuberculosis Prevention in Children Less Than 13 Years of · Phase 1, PHASE2 · not yet recruiting
NCT07342491 — Dasatinib for HIV-1 Reservoir Reduction · Phase 1 · not yet recruiting

Verify against primary sources

ClinicalTrials.gov — authoritative US registry record
WHO ICTRP — international registry index
EU Clinical Trials Register
Sponsor press releases (Google)

Data sources for this page

Trial protocol + status: ClinicalTrials.gov NCT04520659 (US National Library of Medicine, public domain)
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by National Institute of Allergy and Infectious Diseases (NIAID)
Last refreshed: 22 August 2025

Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT04520659.

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing