HEPA filters in classrooms: a new weapon against sick days?

NCT ID NCT07119333

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study tests whether placing HEPA air purifiers in primary school classrooms can reduce student absences caused by respiratory infections like colds and flu. About 72 schools in Norway will be randomly assigned to receive either working purifiers or sham devices. Researchers will track absences over 12-week periods during two winter seasons to see if cleaner air keeps more children in class.

What this could mean

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

Active substance

Air purifiers with HEPA filters

What this could lead to

If effective, air purifiers could become a simple, non-disruptive way to reduce school absences and limit the spread of respiratory infections in classrooms.

What could go wrong

This is an early-stage trial with only 72 schools, and the sham control design means results may be modest. Air purifiers might not significantly cut absences, and the study focuses on a specific age group in Norway.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

respiratory tract infectious disorder

As listed by the trial registrant

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

Contacts and locations

Locations

  • Norwegian Institute of Public Health

    Oslo, Oslo, 0213, Norway