Real-World Effectiveness of Nirsevimab Against RSV-Related and All-Cause Respiratory Tract Infections in Chinese Infants

February 1, 2026 updated by: Han Tongyan

Real-World Effectiveness of Nirsevimab Against RSV-Related and All-Cause Respiratory Tract Infections in Chinese Infants: A Multicenter Cohort Study

A multicenter, retrospective cohort study based on clinical data from seven tertiary hospitals in China will be undertaken. The study aims to evaluate the real-world effectiveness of Nirsevimab in preventing Respiratory Syncytial Virus (RSV) infections and all-cause respiratory infections. Clinical records will be used to compare outcomes between infants who received Nirsevimab and a control group. The study focuses on infants aged 0 to 1 year during the RSV season.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to evaluate the effectiveness of Nirsevimab in preventing RSV-related and all-cause lower respiratory tract infections (LRTI) among infants in a real-world setting.

The target population includes infants aged 0 to 1 year enrolled across seven Chinese tertiary hospitals during the RSV season (September 2024 through April 2025). The study employs a target trial emulation design to compare infants receiving Nirsevimab with a control group of infants who did not receive Nirsevimab.

Outcomes will be assessed over a follow-up period of up to 180 days. Researchers will utilize hospital electronic medical records to identify the incidence of infections, hospitalizations, and admissions to the intensive care unit (ICU). Statistical methods, such as inverse probability of treatment weighting, will be applied to balance the characteristics of the two groups and ensure a valid comparison.

Study Type

Observational

Enrollment (Actual)

816

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
      • Beijing, China, 100191
        • Peking University Third Hospital
      • Beijing, China, 100045
        • Beijing Children's Hospital
      • Beijing, China, 101149
        • Beijing Luhe hospital
      • Shanghai, China, 200092
        • Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine
      • Shenzhen, China, 518000
        • Shenzhen Maternity & Child Healthcare Hospital
    • Inner Mongolia
      • Hohhot, Inner Mongolia, China, 010000
        • Inner Mongolia Maternity and Child Health Care Hospital
    • Shandong
      • Qingdao, Shandong, China, 266000
        • Women and Children's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Infants aged ≤ 1 year entering their first RSV season between September 2024 and April 2025

Description

Inclusion Criteria:

Infants aged ≤ 1 year (including preterm infants) entering their first RSV season.

Exclusion Criteria:

  1. Prior or active RSV infection.
  2. Prior RSV immunization (maternal vaccine or monoclonal antibody).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Nirsevimab group
Infants who received Nirsevimab during the study period.
Biological: Nirsevimab
Nirsevimab will be administered as a single intramuscular dose of 50 mg for infants < 5 kg and 100 mg for infants ≥ 5 kg.
Other Names:
  • Beyfortus
Control group
Infants with health records established at the same study centers during the study period who were eligible for Nirsevimab but did not receive the immunization.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of RSV-related LRTI hospitalization.
Time Frame: From enrollment up to 180 days.
Number of participants admitted to the hospital (inpatient care) with a diagnosis of LRTI and a laboratory-confirmed RSV infection (detected by PCR or antigen testing).
From enrollment up to 180 days.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of all-cause LRTI hospitalization.
Time Frame: From enrollment up to 180 days.
Number of participants admitted to the hospital with a diagnosis of LRTI caused by any pathogen (including RSV, other viruses, or bacteria) or unspecified agents.
From enrollment up to 180 days.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Han Tongyan

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 1, 2025

Primary Completion (Actual)

October 31, 2025

Study Completion (Actual)

October 31, 2025

Study Registration Dates

First Submitted

January 25, 2026

First Submitted That Met QC Criteria

January 25, 2026

First Posted (Actual)

February 2, 2026

Study Record Updates

Last Update Posted (Actual)

February 3, 2026

Last Update Submitted That Met QC Criteria

February 1, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • M20250653

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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