Oseltamivir and Baloxavir Marboxil for Prophylaxis Against Influenza Under a Hospital-based Setting

Not Applicable

Not yet recruiting

Brief Summary: This study aims to randomly assign close contacts of hospitalized influenza virus patients to receive baloxavir marboxil prophylaxis, oseltamivir prophylaxis or no antiviral prophylaxis and monitor the incidence of clinical influenza, evaluating the prophylaxis efficiency of antivirals in a hospital setting.

Detailed Description: This study will enroll hospitalized patients diagnosed with influenza virus infection (index patients) and their roommates who are not infected with the influenza virus (close contacts). The close contacts will be randomly assigned in a 1:1:1 ratio to receive baloxavir marboxil prophylaxis, oseltamivir prophylaxis or no antiviral prophylaxis. The incidence of clinical influenza (confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR) testing, along with fever and one respiratory symptom) will be monitored to evaluate the efficiency of antiviral prophylaxis in a hospital setting. The index patients will receive standard treatment for influenza infection.

Recruitment & Eligibility

Inclusion Criteria

Index patient:
1. Patients or accompanying caregivers hospitalized at participating medical institutions.
2.The subject and/or their legal guardian both agree to participate in this clinical study, sign the informed consent form, and are able to comply with the study requirements for follow-up and completion of all study procedures and assessments.
3.Age ≥ 2 years.
4.Influenza nucleic acid positivity confirmed by throat swab, sputum and other respiratory sample through rapid antigen testing (RAT) or PCR.
Close contact:
1.Patients or accompanying caregivers hospitalized at participating medical institutions.
2.The subject and/or their legal guardian both agree to participate in this clinical study, sign the informed consent form, and are able to comply with the study requirements for follow-up and complete all study procedures and assessments
3.Age ≥ 12 years.
4.Expected to remain hospitalized for ≥ 72 hours.
5.The room must contain at least one hospitalized index patient diagnosed with influenza virus within the past 72 hours, and the contact is expected to stay with the hospitalized index patient in the ward for more than 24 hours.
6.Throat swab on the first day tested negative for influenza virus by PCR.

Exclusion Criteria

Close contacts
1.With known allergies to the active ingredients or excipients of the investigational drug.
2.Close contacts diagnosed with or having experienced an influenza virus infection within the past 12 weeks.
3.Close contacts who have used antiviral drugs (including neuraminidase inhibitors, hemagglutinin inhibitors, and M2 ion channel blockers, such as oseltamivir, zanamivir, peramivir, favipiravir, abidol, baloxavir marboxil, amantadine, rimantadine, or any other antiviral drugs approved by NMPA) within the 2 weeks prior to screening.
4.Close contacts known to be pregnant or breastfeeding.
1. Having experienced fever (axillary temperature ≥37.3°C) in the past 3 days prior to screening.
6.Subjects deemed unsuitable to participate in the study by the investigator.

Arm && Interventions

Group	Intervention	Description
Baloxavir Marboxil	Baloxavir Marboxil	Baloxavir marboxil will be administered on the first day following the close contact's enrollment in this study. Participants weighing ≤80 kg will receive 40 mg of baloxavir marboxil, while those weighing ≥80 kg will receive 80 mg.
Oseltamivir Arm	Oseltamivir	Oseltamivir will be administered once daily for 5 consecutive days following the close contact's enrollment in this study. Participants will receive 75 mg of oseltamivir once each day

Primary Outcome Measures

Name	Time	Method
Incidence of Clinical Influenza within a 5-day period	up to 5 days	Incidence of Clinical Influenza within a 5-day period is defined as the percentage of contacts who become positive for influenza based on reverse-transcriptase polymerase chain reaction (RT-PCR) testing or rapid antigen testing (RAT), along with fever (defined as axillary temperature ≥37.3℃) and at least one respiratory symptom.

Secondary Outcome Measures

Name	Time	Method
Incidence of influenza within a 5-day period	up to 5 days	Incidence of Influenza within a 5-day period is defined as the percentage of contacts who become positive for influenza based on reverse-transcriptase polymerase chain reaction (RT-PCR) testing or rapid antigen testing (RAT).
Incidence of Clinical Influenza within a 10-day period	up to 10 days	Incidence of Clinical Influenza within a 10-day period is defined as the percentage of contacts who become positive for influenza based on reverse-transcriptase polymerase chain reaction (RT-PCR) testing or rapid antigen testing (RAT), along with fever (defined as axillary temperature ≥37.3℃) and at least one respiratory symptom.
Susceptibility to antivirals by phenotyping post-baseline samples with novel mutation	up to 10 days	Susceptibility to antivirals by phenotyping post-baseline samples with novel mutation is defined as the percentage of contacts infected with resistance-associated treatment-emergent influenza variants.