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Enrolling by Invitation

NCT Number: NCT07739446

Randomized Controlled Trial to Evaluate the Efficacy of Surgical Masks in Preventing Acute Respiratory Infections

The goal of this clinical trial is to evaluate the efficacy of surgical masks in preventing acute respiratory tract infections. The main question it aims to answer is:

- Does wearing a mask prevent you from getting acute respiratory tract infections, including influenza and COVID-19

Researchers will compare a surgical mask to no intervention to see if wearing a mask works to prevent acute respiratory infection.

Participants will:

* Wear or not wear a surgical mask every day * Answer a questionnaire every 2 weeks on symptoms, testing status, and behaviors

This trial does not assess if wearing a mask prevents transmission of pathogens when you are already sick. Also, the trial does not assess whether universal masking (where everyone wears masks) works.

Enrolling by Invitation

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Key information

Conditions

Acute Respiratory Infections (ARIs) COVID - 19 COVID-19 Coronaviridae Infections Coronavirus Infections Infections Influenza Influenza, Human Lung Diseases Nidovirales Infections Orthomyxoviridae Infections Pneumonia Pneumonia, Viral RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

20 year–49 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Chiba University/National Institute of Infectious Diseases, Japan Institute for Health Security

Chiba, Japan

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Those who originally do not wear a mask during the influenza season
  • Those aged 20 years or older and under 50 years at the time of providing informed consent
  • If assigned to the mask group, those who can agree to wear a mask when going outdoors for 3 to 4 months during the influenza season (excluding times such as when eating)
  • In the case of the non-mask group, those who can agree, in principle, not to wear a mask for 3 to 4 months during the influenza season
  • Those who can agree to undergo testing for both influenza and COVID-19 on the day of onset or the following day if symptoms suggestive of influenza, COVID-19, or a common cold (such as fever or respiratory symptoms) develop, and to visit a medical institution at their own expense for medical fees
  • Those who usually go out 3 or more days a week
  • Those who have obtained the agreement of cohabiting family members regarding participation
  • Those who, after receiving a thorough explanation regarding participation in this study and with full understanding, have provided written informed consent based on their own free will

Exclusion criteria

  • Those who originally wear a mask during the influenza season and intend to continue doing so in the future
  • Those who are engaged in healthcare, food manufacturing, etc., and wear a mask during regular work
  • Those who are pregnant
  • Those with underlying medical conditions such as chronic liver disease, cancer, or cardiovascular disease
  • Those who have previously experienced allergic symptoms when wearing commercially available non-woven masks
  • Those who are planning long-term overseas travel exceeding one week during the influenza season, including the New Year holidays‡
  • Others who did not provide consent

Treatment and study plan

Surgical masks

Behavioral

Participants in this group are provided with masks and asked to wear them every day

Primary outcomes

  1. Laboratory-confirmed influenza

    Time frame: From start of influenza season to the end of data collection at 14 weeks

    Laboratory-confirmed influenza based on testing done at healthcare facilities

Secondary outcomes

  1. Acute respiratory infection

    Time frame: From start of influenza season to the end of data collection at 14 weeks

    Syndromic outcome based on self-report

  2. Laboratory-confirmed COVID-19

    Time frame: From start of influenza season to the end of data collection at 14 weeks

    Laboratory-confirmed COVID-19 based on testing done at healthcare facilities

  3. Laboratory-confirmed influenza or COVID-19

    Time frame: From start of influenza season to the end of data collection at 14 weeks

    Laboratory-confirmed influenza or COVID-19 based on testing done at healthcare facilities

Other outcomes

  1. Antibody response in sebum specimens

    Time frame: From start of influenza season to the end of data collection at 14 weeks

    Antibody response in sebum specimens collected for laboratory-confirmed influenza cases among participants

Sponsors and collaborators

Lead sponsor

Chiba University

Other

Registry information

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 31, 2026
Registry last updated
Jul 31, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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