A phase II study of inhaled interferon beta

Interferons are an important part of the immune system’s defence against viruses. Research suggests that SARS-CoV-2-infected cells can make proteins that suppress the production of interferons. Furthermore, this coronavirus appears to cause infected cells to produce proteins that weaken the activity of interferons. Perhaps these properties of SARS-CoV-2 against interferons may in part explain its ability to cause severe disease in some people. Some studies have found little detectable interferon in the blood of people with severe COVID-19. In some cases, low levels of interferon were associated with the production of antibodies that attacked interferons, particularly interferon-alpha. This raises the possibility that treatment with other members of the interferon family maybe useful.

A pilot study

Researchers in England conducted a randomized, double-blind, placebo-controlled pilot study of aerosolized interferon-beta vs. placebo. Both interventions were taken once daily for up to 14 consecutive days in hospitalized people with COVID-19.

Participants who received interferon-beta were twice as likely to have an improvement in their condition and to recover faster than those who took the placebo. Further studies are underway in people with COVID-19.

Study details

The Synairgen corporation provided purified interferon-beta-1a for the study. The drug was given at a dose of 6 million international units (IU) daily. Interferon-beta or placebo was dispersed into tiny droplets and inhaled via a nebulizer.

The average profile of the 98 participants at the start of the study was as follows:

  • age – 57 years
  • 59% men; 41% women
  • 80% were white and 20% were people of colour
  • 54% had comorbidities – high blood pressure, cancer, cardiovascular disease, diabetes, chronic lung disease
  • 77% were receiving oxygen via mask or nasal prong
  • participants had symptoms of COVID-19 for 10 days prior to initiating the study interventions

Participants were monitored for up to 28 days.


Participants who received interferon-beta were more likely to recover and to do so faster than participants on placebo.

However, by the 28th day of the study, broadly similar proportions of participants were released from the hospital—81% who had received interferon-beta and 75% who received placebo.

Side effects

As interferon was delivered directly to the throat, airways and lungs rather than into the blood, it likely caused limited side effects. The most common side effect was headache, distributed as follows:

  • interferon-beta – 15%
  • placebo – 10%

More people who received interferon-beta complained about coughing.

Three people died, all of whom received placebo.

Bear in mind

The present study was a well-designed pilot study. Its findings are encouraging but not definitive. The study was not designed to assess the impact of interferon-beta on survival. Larger studies will be needed to provide definitive answers about the role of interferon-beta in people with COVID-19 and its impact on survival. Phase II and III trials of aerosolized interferon-beta are underway.

—Sean R. Hosein


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