July 2020 

Does interferon-lambda have potential in COVID-19?

One part of the immune system, called the innate immune system, can usually detect and respond to invading germs, including viruses, in the early stages of an infection, long before antibodies can be made and T-cells mobilized.

Part of the innate immune system’s defensive response to a virus is the release of interferon-lambda. Lab experiments with cells, animals and viruses suggest that the cells that line the respiratory tract, lungs and gastrointestinal tract, as well as some cells of the immune system called neutrophils, are particularly sensitive to the effects of interferon-lambda. In theory, this interferon could do the following:

  • activate the innate immune system and protect uninfected cells from becoming infected with SARS-CoV-2, thereby preventing people from developing COVID-19
  • slow the production of SARS-CoV-2 in people recently infected with this virus, which could help their immune systems bring the infection under control and help them recover

Scientists need to test the effect of interferon-lambda in animals infected with SARS-CoV-2. Such testing is important to find out if interferon-lambda treatment works or contributes to COVID-19-associated organ injury.

Clinical trials done in people without SARS-CoV-2 infection have suggested that interferon-lambda is relatively well tolerated. A long-lasting formulation of interferon-lambda is available for clinical trials; it can be dosed once weekly. Such a formulation may mean that if this interferon is tested in people with COVID-19, only one or two doses may be necessary. An important issue with interferon-lambda is the timing of such a potential therapy relative to the stage of COVID-19.

—Sean R. Hosein


  1. Prokunina-Olsson L, Alphonse N, Dickenson RE, et al. COVID-19 and emerging viral infections: The case for interferon lambda. Journal of Experimental Medicine. 2020;217(5):e20200653.
  2. Major J, Crotta S, Llorian M, et al. Type I and III interferons disrupt lung epithelial repair during recovery from viral infection. Science. 2020; in press.
  3. O’Brien TR, Thomas DL, Jackson SS, Prokunina-Olsson L, Donnelly RP, Hartmann R. Weak induction of interferon expression by SARS-CoV-2 supports clinical trials of interferon lambda to treat early COVID-19. Clinical Infectious Diseases. 2020; in press.