Could a simple gas shield healthcare workers from COVID-19?

NCT ID NCT04312243

What the study statuses mean

This study's is highlighted.

Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early This study
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This study tested whether breathing in nitric oxide gas could prevent healthcare workers from catching COVID-19. The plan was to enroll 470 workers, but the trial was stopped early with only 24 participants. Workers in the treatment group inhaled the gas at the start and end of each shift for 15 minutes. Because the trial was terminated and very small, we cannot say whether it works or not.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance
inhaled nitric oxide gas
What this could lead to
If it worked, this could point toward a simple preventive measure for healthcare workers at high risk of COVID-19 exposure.
What could go wrong
The trial was terminated early and enrolled only 24 of 470 planned participants, so results are too limited to draw any conclusions. Inhaled nitric oxide can cause methemoglobinemia, requiring careful monitoring.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2

Tests whether the treatment actually works, and watches for side effects, in a larger group.

Participants

24 people

The number who actually took part.

Started

Apr 2020

Finished

Jan 2022

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 99 years

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age ≥18 years 2. Scheduled to work with SARS-CoV-2 infected patients for at least 3 days in a week. Exclusion Criteria: 1. Previous documented SARS-CoV-2 infections and subsequent negative SARS-CoV-2 rt-PCR test. 2. Pregnancy 3. Known hemoglobinopathies. 4. Known anemia

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Massachusetts General Hospital

    Boston, Massachusetts, 02114, United States

More trials for these conditions

Other studies related to the condition(s) this trial covers.